greenplumn pl_exec 源码
greenplumn pl_exec 代码
文件路径：/src/pl/plpgsql/src/pl_exec.c
/*-------------------------------------------------------------------------
*
* pl_exec.c - Executor for the PL/pgSQL
* procedural language
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/pl/plpgsql/src/pl_exec.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <ctype.h>
#include "access/htup_details.h"
#include "access/transam.h"
#include "access/tupconvert.h"
#include "access/tuptoaster.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "executor/execExpr.h"
#include "executor/spi.h"
#include "executor/spi_priv.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "parser/parse_coerce.h"
#include "parser/scansup.h"
#include "storage/proc.h"
#include "tcop/tcopprot.h"
#include "tcop/utility.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
#include "cdb/cdbvars.h"
#include "plpgsql.h"
typedef struct
{
int nargs; /* number of arguments */
Oid *types; /* types of arguments */
Datum *values; /* evaluated argument values */
char *nulls; /* null markers (' '/'n' style) */
} PreparedParamsData;
/*
* All plpgsql function executions within a single transaction share the same
* executor EState for evaluating "simple" expressions. Each function call
* creates its own "eval_econtext" ExprContext within this estate for
* per-evaluation workspace. eval_econtext is freed at normal function exit,
* and the EState is freed at transaction end (in case of error, we assume
* that the abort mechanisms clean it all up). Furthermore, any exception
* block within a function has to have its own eval_econtext separate from
* the containing function's, so that we can clean up ExprContext callbacks
* properly at subtransaction exit. We maintain a stack that tracks the
* individual econtexts so that we can clean up correctly at subxact exit.
*
* This arrangement is a bit tedious to maintain, but it's worth the trouble
* so that we don't have to re-prepare simple expressions on each trip through
* a function. (We assume the case to optimize is many repetitions of a
* function within a transaction.)
*
* However, there's no value in trying to amortize simple expression setup
* across multiple executions of a DO block (inline code block), since there
* can never be any. If we use the shared EState for a DO block, the expr
* state trees are effectively leaked till end of transaction, and that can
* add up if the user keeps on submitting DO blocks. Therefore, each DO block
* has its own simple-expression EState, which is cleaned up at exit from
* plpgsql_inline_handler(). DO blocks still use the simple_econtext_stack,
* though, so that subxact abort cleanup does the right thing.
*/
typedef struct SimpleEcontextStackEntry
{
ExprContext *stack_econtext; /* a stacked econtext */
SubTransactionId xact_subxid; /* ID for current subxact */
struct SimpleEcontextStackEntry *next; /* next stack entry up */
} SimpleEcontextStackEntry;
static EState *shared_simple_eval_estate = NULL;
static SimpleEcontextStackEntry *simple_econtext_stack = NULL;
/*
* Memory management within a plpgsql function generally works with three
* contexts:
*
* 1. Function-call-lifespan data, such as variable values, is kept in the
* "main" context, a/k/a the "SPI Proc" context established by SPI_connect().
* This is usually the CurrentMemoryContext while running code in this module
* (which is not good, because careless coding can easily cause
* function-lifespan memory leaks, but we live with it for now).
*
* 2. Some statement-execution routines need statement-lifespan workspace.
* A suitable context is created on-demand by get_stmt_mcontext(), and must
* be reset at the end of the requesting routine. Error recovery will clean
* it up automatically. Nested statements requiring statement-lifespan
* workspace will result in a stack of such contexts, see push_stmt_mcontext().
*
* 3. We use the eval_econtext's per-tuple memory context for expression
* evaluation, and as a general-purpose workspace for short-lived allocations.
* Such allocations usually aren't explicitly freed, but are left to be
* cleaned up by a context reset, typically done by exec_eval_cleanup().
*
* These macros are for use in making short-lived allocations:
*/
#define get_eval_mcontext(estate) \
((estate)->eval_econtext->ecxt_per_tuple_memory)
#define eval_mcontext_alloc(estate, sz) \
MemoryContextAlloc(get_eval_mcontext(estate), sz)
#define eval_mcontext_alloc0(estate, sz) \
MemoryContextAllocZero(get_eval_mcontext(estate), sz)
/*
* We use a session-wide hash table for caching cast information.
*
* Once built, the compiled expression trees (cast_expr fields) survive for
* the life of the session. At some point it might be worth invalidating
* those after pg_cast changes, but for the moment we don't bother.
*
* The evaluation state trees (cast_exprstate) are managed in the same way as
* simple expressions (i.e., we assume cast expressions are always simple).
*
* As with simple expressions, DO blocks don't use the shared hash table but
* must have their own. This isn't ideal, but we don't want to deal with
* multiple simple_eval_estates within a DO block.
*/
typedef struct /* lookup key for cast info */
{
/* NB: we assume this struct contains no padding bytes */
Oid srctype; /* source type for cast */
Oid dsttype; /* destination type for cast */
int32 srctypmod; /* source typmod for cast */
int32 dsttypmod; /* destination typmod for cast */
} plpgsql_CastHashKey;
typedef struct /* cast_hash table entry */
{
plpgsql_CastHashKey key; /* hash key --- MUST BE FIRST */
Expr *cast_expr; /* cast expression, or NULL if no-op cast */
CachedExpression *cast_cexpr; /* cached expression backing the above */
/* ExprState is valid only when cast_lxid matches current LXID */
ExprState *cast_exprstate; /* expression's eval tree */
bool cast_in_use; /* true while we're executing eval tree */
LocalTransactionId cast_lxid;
} plpgsql_CastHashEntry;
static MemoryContext shared_cast_context = NULL;
static HTAB *shared_cast_hash = NULL;
/*
* LOOP_RC_PROCESSING encapsulates common logic for looping statements to
* handle return/exit/continue result codes from the loop body statement(s).
* It's meant to be used like this:
*
* int rc = PLPGSQL_RC_OK;
* for (...)
* {
* ...
* rc = exec_stmts(estate, stmt->body);
* LOOP_RC_PROCESSING(stmt->label, break);
* ...
* }
* return rc;
*
* If execution of the loop should terminate, LOOP_RC_PROCESSING will execute
* "exit_action" (typically a "break" or "goto"), after updating "rc" to the
* value the current statement should return. If execution should continue,
* LOOP_RC_PROCESSING will do nothing except reset "rc" to PLPGSQL_RC_OK.
*
* estate and rc are implicit arguments to the macro.
* estate->exitlabel is examined and possibly updated.
*/
#define LOOP_RC_PROCESSING(looplabel, exit_action) \
if (rc == PLPGSQL_RC_RETURN) \
{ \
/* RETURN, so propagate RC_RETURN out */ \
exit_action; \
} \
else if (rc == PLPGSQL_RC_EXIT) \
{ \
if (estate->exitlabel == NULL) \
{ \
/* unlabelled EXIT terminates this loop */ \
rc = PLPGSQL_RC_OK; \
exit_action; \
} \
else if ((looplabel) != NULL && \
strcmp(looplabel, estate->exitlabel) == 0) \
{ \
/* labelled EXIT matching this loop, so terminate loop */ \
estate->exitlabel = NULL; \
rc = PLPGSQL_RC_OK; \
exit_action; \
} \
else \
{ \
/* non-matching labelled EXIT, propagate RC_EXIT out */ \
exit_action; \
} \
} \
else if (rc == PLPGSQL_RC_CONTINUE) \
{ \
if (estate->exitlabel == NULL) \
{ \
/* unlabelled CONTINUE matches this loop, so continue in loop */ \
rc = PLPGSQL_RC_OK; \
} \
else if ((looplabel) != NULL && \
strcmp(looplabel, estate->exitlabel) == 0) \
{ \
/* labelled CONTINUE matching this loop, so continue in loop */ \
estate->exitlabel = NULL; \
rc = PLPGSQL_RC_OK; \
} \
else \
{ \
/* non-matching labelled CONTINUE, propagate RC_CONTINUE out */ \
exit_action; \
} \
} \
else \
Assert(rc == PLPGSQL_RC_OK)
/************************************************************
* Local function forward declarations
************************************************************/
static void coerce_function_result_tuple(PLpgSQL_execstate *estate,
TupleDesc tupdesc);
static void plpgsql_exec_error_callback(void *arg);
static void copy_plpgsql_datums(PLpgSQL_execstate *estate,
PLpgSQL_function *func);
static void plpgsql_fulfill_promise(PLpgSQL_execstate *estate,
PLpgSQL_var *var);
static MemoryContext get_stmt_mcontext(PLpgSQL_execstate *estate);
static void push_stmt_mcontext(PLpgSQL_execstate *estate);
static void pop_stmt_mcontext(PLpgSQL_execstate *estate);
static int exec_stmt_block(PLpgSQL_execstate *estate,
PLpgSQL_stmt_block *block);
static int exec_stmts(PLpgSQL_execstate *estate,
List *stmts);
static int exec_stmt(PLpgSQL_execstate *estate,
PLpgSQL_stmt *stmt);
static int exec_stmt_assign(PLpgSQL_execstate *estate,
PLpgSQL_stmt_assign *stmt);
static int exec_stmt_perform(PLpgSQL_execstate *estate,
PLpgSQL_stmt_perform *stmt);
static int exec_stmt_call(PLpgSQL_execstate *estate,
PLpgSQL_stmt_call *stmt);
static int exec_stmt_getdiag(PLpgSQL_execstate *estate,
PLpgSQL_stmt_getdiag *stmt);
static int exec_stmt_if(PLpgSQL_execstate *estate,
PLpgSQL_stmt_if *stmt);
static int exec_stmt_case(PLpgSQL_execstate *estate,
PLpgSQL_stmt_case *stmt);
static int exec_stmt_loop(PLpgSQL_execstate *estate,
PLpgSQL_stmt_loop *stmt);
static int exec_stmt_while(PLpgSQL_execstate *estate,
PLpgSQL_stmt_while *stmt);
static int exec_stmt_fori(PLpgSQL_execstate *estate,
PLpgSQL_stmt_fori *stmt);
static int exec_stmt_fors(PLpgSQL_execstate *estate,
PLpgSQL_stmt_fors *stmt);
static int exec_stmt_forc(PLpgSQL_execstate *estate,
PLpgSQL_stmt_forc *stmt);
static int exec_stmt_foreach_a(PLpgSQL_execstate *estate,
PLpgSQL_stmt_foreach_a *stmt);
static int exec_stmt_open(PLpgSQL_execstate *estate,
PLpgSQL_stmt_open *stmt);
static int exec_stmt_fetch(PLpgSQL_execstate *estate,
PLpgSQL_stmt_fetch *stmt);
static int exec_stmt_close(PLpgSQL_execstate *estate,
PLpgSQL_stmt_close *stmt);
static int exec_stmt_exit(PLpgSQL_execstate *estate,
PLpgSQL_stmt_exit *stmt);
static int exec_stmt_return(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return *stmt);
static int exec_stmt_return_next(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_next *stmt);
static int exec_stmt_return_query(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_query *stmt);
static int exec_stmt_raise(PLpgSQL_execstate *estate,
PLpgSQL_stmt_raise *stmt);
static int exec_stmt_assert(PLpgSQL_execstate *estate,
PLpgSQL_stmt_assert *stmt);
static int exec_stmt_execsql(PLpgSQL_execstate *estate,
PLpgSQL_stmt_execsql *stmt);
static int exec_stmt_dynexecute(PLpgSQL_execstate *estate,
PLpgSQL_stmt_dynexecute *stmt);
static int exec_stmt_dynfors(PLpgSQL_execstate *estate,
PLpgSQL_stmt_dynfors *stmt);
static int exec_stmt_commit(PLpgSQL_execstate *estate,
PLpgSQL_stmt_commit *stmt);
static int exec_stmt_rollback(PLpgSQL_execstate *estate,
PLpgSQL_stmt_rollback *stmt);
static int exec_stmt_set(PLpgSQL_execstate *estate,
PLpgSQL_stmt_set *stmt);
static void plpgsql_estate_setup(PLpgSQL_execstate *estate,
PLpgSQL_function *func,
ReturnSetInfo *rsi,
EState *simple_eval_estate);
static void exec_eval_cleanup(PLpgSQL_execstate *estate);
static void exec_prepare_plan(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr, int cursorOptions,
bool keepplan);
static void exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr);
static void exec_save_simple_expr(PLpgSQL_expr *expr, CachedPlan *cplan);
static void exec_check_rw_parameter(PLpgSQL_expr *expr, int target_dno);
static bool contains_target_param(Node *node, int *target_dno);
static bool exec_eval_simple_expr(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
Datum *result,
bool *isNull,
Oid *rettype,
int32 *rettypmod);
static void exec_assign_expr(PLpgSQL_execstate *estate,
PLpgSQL_datum *target,
PLpgSQL_expr *expr);
static void exec_assign_c_string(PLpgSQL_execstate *estate,
PLpgSQL_datum *target,
const char *str);
static void exec_assign_value(PLpgSQL_execstate *estate,
PLpgSQL_datum *target,
Datum value, bool isNull,
Oid valtype, int32 valtypmod);
static void exec_eval_datum(PLpgSQL_execstate *estate,
PLpgSQL_datum *datum,
Oid *typeid,
int32 *typetypmod,
Datum *value,
bool *isnull);
static int exec_eval_integer(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
bool *isNull);
static bool exec_eval_boolean(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
bool *isNull);
static Datum exec_eval_expr(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
bool *isNull,
Oid *rettype,
int32 *rettypmod);
static int exec_run_select(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr, int64 maxtuples, Portal *portalP);
static int exec_for_query(PLpgSQL_execstate *estate, PLpgSQL_stmt_forq *stmt,
Portal portal, bool prefetch_ok);
static ParamListInfo setup_param_list(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr);
static ParamExternData *plpgsql_param_fetch(ParamListInfo params,
int paramid, bool speculative,
ParamExternData *workspace);
static void plpgsql_param_compile(ParamListInfo params, Param *param,
ExprState *state,
Datum *resv, bool *resnull);
static void plpgsql_param_eval_var(ExprState *state, ExprEvalStep *op,
ExprContext *econtext);
static void plpgsql_param_eval_var_ro(ExprState *state, ExprEvalStep *op,
ExprContext *econtext);
static void plpgsql_param_eval_recfield(ExprState *state, ExprEvalStep *op,
ExprContext *econtext);
static void plpgsql_param_eval_generic(ExprState *state, ExprEvalStep *op,
ExprContext *econtext);
static void plpgsql_param_eval_generic_ro(ExprState *state, ExprEvalStep *op,
ExprContext *econtext);
static void exec_move_row(PLpgSQL_execstate *estate,
PLpgSQL_variable *target,
HeapTuple tup, TupleDesc tupdesc);
static ExpandedRecordHeader *make_expanded_record_for_rec(PLpgSQL_execstate *estate,
PLpgSQL_rec *rec,
TupleDesc srctupdesc,
ExpandedRecordHeader *srcerh);
static void exec_move_row_from_fields(PLpgSQL_execstate *estate,
PLpgSQL_variable *target,
ExpandedRecordHeader *newerh,
Datum *values, bool *nulls,
TupleDesc tupdesc);
static bool compatible_tupdescs(TupleDesc src_tupdesc, TupleDesc dst_tupdesc);
static HeapTuple make_tuple_from_row(PLpgSQL_execstate *estate,
PLpgSQL_row *row,
TupleDesc tupdesc);
static TupleDesc deconstruct_composite_datum(Datum value,
HeapTupleData *tmptup);
static void exec_move_row_from_datum(PLpgSQL_execstate *estate,
PLpgSQL_variable *target,
Datum value);
static void instantiate_empty_record_variable(PLpgSQL_execstate *estate,
PLpgSQL_rec *rec);
static char *convert_value_to_string(PLpgSQL_execstate *estate,
Datum value, Oid valtype);
static Datum exec_cast_value(PLpgSQL_execstate *estate,
Datum value, bool *isnull,
Oid valtype, int32 valtypmod,
Oid reqtype, int32 reqtypmod);
static plpgsql_CastHashEntry *get_cast_hashentry(PLpgSQL_execstate *estate,
Oid srctype, int32 srctypmod,
Oid dsttype, int32 dsttypmod);
static void exec_init_tuple_store(PLpgSQL_execstate *estate);
static void exec_set_found(PLpgSQL_execstate *estate, bool state);
static void plpgsql_create_econtext(PLpgSQL_execstate *estate);
static void plpgsql_destroy_econtext(PLpgSQL_execstate *estate);
static void assign_simple_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
Datum newvalue, bool isnull, bool freeable);
static void assign_text_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
const char *str);
static void assign_record_var(PLpgSQL_execstate *estate, PLpgSQL_rec *rec,
ExpandedRecordHeader *erh);
static PreparedParamsData *exec_eval_using_params(PLpgSQL_execstate *estate,
List *params);
static Portal exec_dynquery_with_params(PLpgSQL_execstate *estate,
PLpgSQL_expr *dynquery, List *params,
const char *portalname, int cursorOptions);
static char *format_expr_params(PLpgSQL_execstate *estate,
const PLpgSQL_expr *expr);
static char *format_preparedparamsdata(PLpgSQL_execstate *estate,
const PreparedParamsData *ppd);
/* ----------
* plpgsql_exec_function Called by the call handler for
* function execution.
*
* This is also used to execute inline code blocks (DO blocks). The only
* difference that this code is aware of is that for a DO block, we want
* to use a private simple_eval_estate, which is created and passed in by
* the caller. For regular functions, pass NULL, which implies using
* shared_simple_eval_estate. (When using a private simple_eval_estate,
* we must also use a private cast hashtable, but that's taken care of
* within plpgsql_estate_setup.)
* ----------
*/
Datum
plpgsql_exec_function(PLpgSQL_function *func, FunctionCallInfo fcinfo,
EState *simple_eval_estate, bool atomic)
{
PLpgSQL_execstate estate;
ErrorContextCallback plerrcontext;
int i;
int rc;
/*
* Setup the execution state
*/
plpgsql_estate_setup(&estate, func, (ReturnSetInfo *) fcinfo->resultinfo,
simple_eval_estate);
estate.atomic = atomic;
/*
* Setup error traceback support for ereport()
*/
plerrcontext.callback = plpgsql_exec_error_callback;
plerrcontext.arg = &estate;
plerrcontext.previous = error_context_stack;
error_context_stack = &plerrcontext;
/*
* Make local execution copies of all the datums
*/
estate.err_text = gettext_noop("during initialization of execution state");
copy_plpgsql_datums(&estate, func);
/*
* Store the actual call argument values into the appropriate variables
*/
estate.err_text = gettext_noop("while storing call arguments into local variables");
for (i = 0; i < func->fn_nargs; i++)
{
int n = func->fn_argvarnos[i];
switch (estate.datums[n]->dtype)
{
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) estate.datums[n];
assign_simple_var(&estate, var,
fcinfo->args[i].value,
fcinfo->args[i].isnull,
false);
/*
* Force any array-valued parameter to be stored in
* expanded form in our local variable, in hopes of
* improving efficiency of uses of the variable. (This is
* a hack, really: why only arrays? Need more thought
* about which cases are likely to win. See also
* typisarray-specific heuristic in exec_assign_value.)
*
* Special cases: If passed a R/W expanded pointer, assume
* we can commandeer the object rather than having to copy
* it. If passed a R/O expanded pointer, just keep it as
* the value of the variable for the moment. (We'll force
* it to R/W if the variable gets modified, but that may
* very well never happen.)
*/
if (!var->isnull && var->datatype->typisarray)
{
if (VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(var->value)))
{
/* take ownership of R/W object */
assign_simple_var(&estate, var,
TransferExpandedObject(var->value,
estate.datum_context),
false,
true);
}
else if (VARATT_IS_EXTERNAL_EXPANDED_RO(DatumGetPointer(var->value)))
{
/* R/O pointer, keep it as-is until assigned to */
}
else
{
/* flat array, so force to expanded form */
assign_simple_var(&estate, var,
expand_array(var->value,
estate.datum_context,
NULL),
false,
true);
}
}
}
break;
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) estate.datums[n];
if (!fcinfo->args[i].isnull)
{
/* Assign row value from composite datum */
exec_move_row_from_datum(&estate,
(PLpgSQL_variable *) rec,
fcinfo->args[i].value);
}
else
{
/* If arg is null, set variable to null */
exec_move_row(&estate, (PLpgSQL_variable *) rec,
NULL, NULL);
}
/* clean up after exec_move_row() */
exec_eval_cleanup(&estate);
}
break;
default:
/* Anything else should not be an argument variable */
elog(ERROR, "unrecognized dtype: %d", func->datums[i]->dtype);
}
}
estate.err_text = gettext_noop("during function entry");
/*
* Set the magic variable FOUND to false
*/
exec_set_found(&estate, false);
/*
* Let the instrumentation plugin peek at this function
*/
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_beg)
((*plpgsql_plugin_ptr)->func_beg) (&estate, func);
/*
* Now call the toplevel block of statements
*/
estate.err_text = NULL;
estate.err_stmt = (PLpgSQL_stmt *) (func->action);
rc = exec_stmt(&estate, (PLpgSQL_stmt *) func->action);
if (rc != PLPGSQL_RC_RETURN)
{
estate.err_stmt = NULL;
estate.err_text = NULL;
ereport(ERROR,
(errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
errmsg("control reached end of function without RETURN")));
}
/*
* We got a return value - process it
*/
estate.err_stmt = NULL;
estate.err_text = gettext_noop("while casting return value to function's return type");
fcinfo->isnull = estate.retisnull;
if (estate.retisset)
{
ReturnSetInfo *rsi = estate.rsi;
/* Check caller can handle a set result */
if (!rsi || !IsA(rsi, ReturnSetInfo) ||
(rsi->allowedModes & SFRM_Materialize) == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
rsi->returnMode = SFRM_Materialize;
/* If we produced any tuples, send back the result */
if (estate.tuple_store)
{
MemoryContext oldcxt;
rsi->setResult = estate.tuple_store;
oldcxt = MemoryContextSwitchTo(estate.tuple_store_cxt);
rsi->setDesc = CreateTupleDescCopy(estate.tuple_store_desc);
MemoryContextSwitchTo(oldcxt);
}
estate.retval = (Datum) 0;
fcinfo->isnull = true;
}
else if (!estate.retisnull)
{
/*
* Cast result value to function's declared result type, and copy it
* out to the upper executor memory context. We must treat tuple
* results specially in order to deal with cases like rowtypes
* involving dropped columns.
*/
if (estate.retistuple)
{
/* Don't need coercion if rowtype is known to match */
if (func->fn_rettype == estate.rettype &&
func->fn_rettype != RECORDOID)
{
/*
* Copy the tuple result into upper executor memory context.
* However, if we have a R/W expanded datum, we can just
* transfer its ownership out to the upper context.
*/
estate.retval = SPI_datumTransfer(estate.retval,
false,
-1);
}
else
{
/*
* Need to look up the expected result type. XXX would be
* better to cache the tupdesc instead of repeating
* get_call_result_type(), but the only easy place to save it
* is in the PLpgSQL_function struct, and that's too
* long-lived: composite types could change during the
* existence of a PLpgSQL_function.
*/
Oid resultTypeId;
TupleDesc tupdesc;
switch (get_call_result_type(fcinfo, &resultTypeId, &tupdesc))
{
case TYPEFUNC_COMPOSITE:
/* got the expected result rowtype, now coerce it */
coerce_function_result_tuple(&estate, tupdesc);
break;
case TYPEFUNC_COMPOSITE_DOMAIN:
/* got the expected result rowtype, now coerce it */
coerce_function_result_tuple(&estate, tupdesc);
/* and check domain constraints */
/* XXX allowing caching here would be good, too */
domain_check(estate.retval, false, resultTypeId,
NULL, NULL);
break;
case TYPEFUNC_RECORD:
/*
* Failed to determine actual type of RECORD. We
* could raise an error here, but what this means in
* practice is that the caller is expecting any old
* generic rowtype, so we don't really need to be
* restrictive. Pass back the generated result as-is.
*/
estate.retval = SPI_datumTransfer(estate.retval,
false,
-1);
break;
default:
/* shouldn't get here if retistuple is true ... */
elog(ERROR, "return type must be a row type");
break;
}
}
}
else
{
/* Scalar case: use exec_cast_value */
estate.retval = exec_cast_value(&estate,
estate.retval,
&fcinfo->isnull,
estate.rettype,
-1,
func->fn_rettype,
-1);
/*
* If the function's return type isn't by value, copy the value
* into upper executor memory context. However, if we have a R/W
* expanded datum, we can just transfer its ownership out to the
* upper executor context.
*/
if (!fcinfo->isnull && !func->fn_retbyval)
estate.retval = SPI_datumTransfer(estate.retval,
false,
func->fn_rettyplen);
}
}
else
{
/*
* We're returning a NULL, which normally requires no conversion work
* regardless of datatypes. But, if we are casting it to a domain
* return type, we'd better check that the domain's constraints pass.
*/
if (func->fn_retisdomain)
estate.retval = exec_cast_value(&estate,
estate.retval,
&fcinfo->isnull,
estate.rettype,
-1,
func->fn_rettype,
-1);
}
estate.err_text = gettext_noop("during function exit");
/*
* Let the instrumentation plugin peek at this function
*/
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_end)
((*plpgsql_plugin_ptr)->func_end) (&estate, func);
/* Clean up any leftover temporary memory */
plpgsql_destroy_econtext(&estate);
exec_eval_cleanup(&estate);
/* stmt_mcontext will be destroyed when function's main context is */
/*
* Pop the error context stack
*/
error_context_stack = plerrcontext.previous;
/*
* Return the function's result
*/
return estate.retval;
}
/*
* Helper for plpgsql_exec_function: coerce composite result to the specified
* tuple descriptor, and copy it out to upper executor memory. This is split
* out mostly for cosmetic reasons --- the logic would be very deeply nested
* otherwise.
*
* estate->retval is updated in-place.
*/
static void
coerce_function_result_tuple(PLpgSQL_execstate *estate, TupleDesc tupdesc)
{
HeapTuple rettup;
TupleDesc retdesc;
TupleConversionMap *tupmap;
/* We assume exec_stmt_return verified that result is composite */
Assert(type_is_rowtype(estate->rettype));
/* We can special-case expanded records for speed */
if (VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(estate->retval)))
{
ExpandedRecordHeader *erh = (ExpandedRecordHeader *) DatumGetEOHP(estate->retval);
Assert(erh->er_magic == ER_MAGIC);
/* Extract record's TupleDesc */
retdesc = expanded_record_get_tupdesc(erh);
/* check rowtype compatibility */
tupmap = convert_tuples_by_position(retdesc,
tupdesc,
gettext_noop("returned record type does not match expected record type"));
/* it might need conversion */
if (tupmap)
{
rettup = expanded_record_get_tuple(erh);
Assert(rettup);
rettup = execute_attr_map_tuple(rettup, tupmap);
/*
* Copy tuple to upper executor memory, as a tuple Datum. Make
* sure it is labeled with the caller-supplied tuple type.
*/
estate->retval = PointerGetDatum(SPI_returntuple(rettup, tupdesc));
/* no need to free map, we're about to return anyway */
}
else
{
/*
* We need only copy result into upper executor memory context.
* However, if we have a R/W expanded datum, we can just transfer
* its ownership out to the upper executor context.
*/
estate->retval = SPI_datumTransfer(estate->retval,
false,
-1);
}
}
else
{
/* Convert composite datum to a HeapTuple and TupleDesc */
HeapTupleData tmptup;
retdesc = deconstruct_composite_datum(estate->retval, &tmptup);
rettup = &tmptup;
/* check rowtype compatibility */
tupmap = convert_tuples_by_position(retdesc,
tupdesc,
gettext_noop("returned record type does not match expected record type"));
/* it might need conversion */
if (tupmap)
rettup = execute_attr_map_tuple(rettup, tupmap);
/*
* Copy tuple to upper executor memory, as a tuple Datum. Make sure
* it is labeled with the caller-supplied tuple type.
*/
estate->retval = PointerGetDatum(SPI_returntuple(rettup, tupdesc));
/* no need to free map, we're about to return anyway */
ReleaseTupleDesc(retdesc);
}
}
/* ----------
* plpgsql_exec_trigger Called by the call handler for
* trigger execution.
* ----------
*/
HeapTuple
plpgsql_exec_trigger(PLpgSQL_function *func,
TriggerData *trigdata)
{
PLpgSQL_execstate estate;
ErrorContextCallback plerrcontext;
int rc;
TupleDesc tupdesc;
PLpgSQL_rec *rec_new,
*rec_old;
HeapTuple rettup;
/*
* Setup the execution state
*/
plpgsql_estate_setup(&estate, func, NULL, NULL);
estate.trigdata = trigdata;
/*
* Setup error traceback support for ereport()
*/
plerrcontext.callback = plpgsql_exec_error_callback;
plerrcontext.arg = &estate;
plerrcontext.previous = error_context_stack;
error_context_stack = &plerrcontext;
/*
* Make local execution copies of all the datums
*/
estate.err_text = gettext_noop("during initialization of execution state");
copy_plpgsql_datums(&estate, func);
/*
* Put the OLD and NEW tuples into record variables
*
* We set up expanded records for both variables even though only one may
* have a value. This allows record references to succeed in functions
* that are used for multiple trigger types. For example, we might have a
* test like "if (TG_OP = 'INSERT' and NEW.foo = 'xyz')", which should
* work regardless of the current trigger type. If a value is actually
* fetched from an unsupplied tuple, it will read as NULL.
*/
tupdesc = RelationGetDescr(trigdata->tg_relation);
rec_new = (PLpgSQL_rec *) (estate.datums[func->new_varno]);
rec_old = (PLpgSQL_rec *) (estate.datums[func->old_varno]);
rec_new->erh = make_expanded_record_from_tupdesc(tupdesc,
estate.datum_context);
rec_old->erh = make_expanded_record_from_exprecord(rec_new->erh,
estate.datum_context);
if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
{
/*
* Per-statement triggers don't use OLD/NEW variables
*/
}
else if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
{
expanded_record_set_tuple(rec_new->erh, trigdata->tg_trigtuple,
false, false);
}
else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
{
expanded_record_set_tuple(rec_new->erh, trigdata->tg_newtuple,
false, false);
expanded_record_set_tuple(rec_old->erh, trigdata->tg_trigtuple,
false, false);
/*
* In BEFORE trigger, stored generated columns are not computed yet,
* so make them null in the NEW row. (Only needed in UPDATE branch;
* in the INSERT case, they are already null, but in UPDATE, the field
* still contains the old value.) Alternatively, we could construct a
* whole new row structure without the generated columns, but this way
* seems more efficient and potentially less confusing.
*/
if (tupdesc->constr && tupdesc->constr->has_generated_stored &&
TRIGGER_FIRED_BEFORE(trigdata->tg_event))
{
for (int i = 0; i < tupdesc->natts; i++)
if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
expanded_record_set_field_internal(rec_new->erh,
i + 1,
(Datum) 0,
true, /* isnull */
false, false);
}
}
else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
{
expanded_record_set_tuple(rec_old->erh, trigdata->tg_trigtuple,
false, false);
}
else
elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, or UPDATE");
/* Make transition tables visible to this SPI connection */
rc = SPI_register_trigger_data(trigdata);
Assert(rc >= 0);
estate.err_text = gettext_noop("during function entry");
/*
* Set the magic variable FOUND to false
*/
exec_set_found(&estate, false);
/*
* Let the instrumentation plugin peek at this function
*/
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_beg)
((*plpgsql_plugin_ptr)->func_beg) (&estate, func);
/*
* Now call the toplevel block of statements
*/
estate.err_text = NULL;
estate.err_stmt = (PLpgSQL_stmt *) (func->action);
rc = exec_stmt(&estate, (PLpgSQL_stmt *) func->action);
if (rc != PLPGSQL_RC_RETURN)
{
estate.err_stmt = NULL;
estate.err_text = NULL;
ereport(ERROR,
(errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
errmsg("control reached end of trigger procedure without RETURN")));
}
estate.err_stmt = NULL;
estate.err_text = gettext_noop("during function exit");
if (estate.retisset)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("trigger procedure cannot return a set")));
/*
* Check that the returned tuple structure has the same attributes, the
* relation that fired the trigger has. A per-statement trigger always
* needs to return NULL, so we ignore any return value the function itself
* produces (XXX: is this a good idea?)
*
* XXX This way it is possible, that the trigger returns a tuple where
* attributes don't have the correct atttypmod's length. It's up to the
* trigger's programmer to ensure that this doesn't happen. Jan
*/
if (estate.retisnull || !TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
rettup = NULL;
else
{
TupleDesc retdesc;
TupleConversionMap *tupmap;
/* We assume exec_stmt_return verified that result is composite */
Assert(type_is_rowtype(estate.rettype));
/* We can special-case expanded records for speed */
if (VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(estate.retval)))
{
ExpandedRecordHeader *erh = (ExpandedRecordHeader *) DatumGetEOHP(estate.retval);
Assert(erh->er_magic == ER_MAGIC);
/* Extract HeapTuple and TupleDesc */
rettup = expanded_record_get_tuple(erh);
Assert(rettup);
retdesc = expanded_record_get_tupdesc(erh);
if (retdesc != RelationGetDescr(trigdata->tg_relation))
{
/* check rowtype compatibility */
tupmap = convert_tuples_by_position(retdesc,
RelationGetDescr(trigdata->tg_relation),
gettext_noop("returned row structure does not match the structure of the triggering table"));
/* it might need conversion */
if (tupmap)
rettup = execute_attr_map_tuple(rettup, tupmap);
/* no need to free map, we're about to return anyway */
}
/*
* Copy tuple to upper executor memory. But if user just did
* "return new" or "return old" without changing anything, there's
* no need to copy; we can return the original tuple (which will
* save a few cycles in trigger.c as well as here).
*/
if (rettup != trigdata->tg_newtuple &&
rettup != trigdata->tg_trigtuple)
rettup = SPI_copytuple(rettup);
}
else
{
/* Convert composite datum to a HeapTuple and TupleDesc */
HeapTupleData tmptup;
retdesc = deconstruct_composite_datum(estate.retval, &tmptup);
rettup = &tmptup;
/* check rowtype compatibility */
tupmap = convert_tuples_by_position(retdesc,
RelationGetDescr(trigdata->tg_relation),
gettext_noop("returned row structure does not match the structure of the triggering table"));
/* it might need conversion */
if (tupmap)
rettup = execute_attr_map_tuple(rettup, tupmap);
ReleaseTupleDesc(retdesc);
/* no need to free map, we're about to return anyway */
/* Copy tuple to upper executor memory */
rettup = SPI_copytuple(rettup);
}
}
/*
* Let the instrumentation plugin peek at this function
*/
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_end)
((*plpgsql_plugin_ptr)->func_end) (&estate, func);
/* Clean up any leftover temporary memory */
plpgsql_destroy_econtext(&estate);
exec_eval_cleanup(&estate);
/* stmt_mcontext will be destroyed when function's main context is */
/*
* Pop the error context stack
*/
error_context_stack = plerrcontext.previous;
/*
* Return the trigger's result
*/
return rettup;
}
/* ----------
* plpgsql_exec_event_trigger Called by the call handler for
* event trigger execution.
* ----------
*/
void
plpgsql_exec_event_trigger(PLpgSQL_function *func, EventTriggerData *trigdata)
{
PLpgSQL_execstate estate;
ErrorContextCallback plerrcontext;
int rc;
/*
* Setup the execution state
*/
plpgsql_estate_setup(&estate, func, NULL, NULL);
estate.evtrigdata = trigdata;
/*
* Setup error traceback support for ereport()
*/
plerrcontext.callback = plpgsql_exec_error_callback;
plerrcontext.arg = &estate;
plerrcontext.previous = error_context_stack;
error_context_stack = &plerrcontext;
/*
* Make local execution copies of all the datums
*/
estate.err_text = gettext_noop("during initialization of execution state");
copy_plpgsql_datums(&estate, func);
/*
* Let the instrumentation plugin peek at this function
*/
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_beg)
((*plpgsql_plugin_ptr)->func_beg) (&estate, func);
/*
* Now call the toplevel block of statements
*/
estate.err_text = NULL;
estate.err_stmt = (PLpgSQL_stmt *) (func->action);
rc = exec_stmt(&estate, (PLpgSQL_stmt *) func->action);
if (rc != PLPGSQL_RC_RETURN)
{
estate.err_stmt = NULL;
estate.err_text = NULL;
ereport(ERROR,
(errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
errmsg("control reached end of trigger procedure without RETURN")));
}
estate.err_stmt = NULL;
estate.err_text = gettext_noop("during function exit");
/*
* Let the instrumentation plugin peek at this function
*/
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->func_end)
((*plpgsql_plugin_ptr)->func_end) (&estate, func);
/* Clean up any leftover temporary memory */
plpgsql_destroy_econtext(&estate);
exec_eval_cleanup(&estate);
/* stmt_mcontext will be destroyed when function's main context is */
/*
* Pop the error context stack
*/
error_context_stack = plerrcontext.previous;
return;
}
/*
* error context callback to let us supply a call-stack traceback
*/
static void
plpgsql_exec_error_callback(void *arg)
{
PLpgSQL_execstate *estate = (PLpgSQL_execstate *) arg;
if (estate->err_text != NULL)
{
/*
* We don't expend the cycles to run gettext() on err_text unless we
* actually need it. Therefore, places that set up err_text should
* use gettext_noop() to ensure the strings get recorded in the
* message dictionary.
*
* If both err_text and err_stmt are set, use the err_text as
* description, but report the err_stmt's line number. When err_stmt
* is not set, we're in function entry/exit, or some such place not
* attached to a specific line number.
*/
if (estate->err_stmt != NULL)
{
/*
* translator: last %s is a phrase such as "during statement block
* local variable initialization"
*/
errcontext("PL/pgSQL function %s line %d %s",
estate->func->fn_signature,
estate->err_stmt->lineno,
_(estate->err_text));
}
else
{
/*
* translator: last %s is a phrase such as "while storing call
* arguments into local variables"
*/
errcontext("PL/pgSQL function %s %s",
estate->func->fn_signature,
_(estate->err_text));
}
}
else if (estate->err_stmt != NULL)
{
/* translator: last %s is a plpgsql statement type name */
errcontext("PL/pgSQL function %s line %d at %s",
estate->func->fn_signature,
estate->err_stmt->lineno,
plpgsql_stmt_typename(estate->err_stmt));
}
else
errcontext("PL/pgSQL function %s",
estate->func->fn_signature);
}
/* ----------
* Support function for initializing local execution variables
* ----------
*/
static void
copy_plpgsql_datums(PLpgSQL_execstate *estate,
PLpgSQL_function *func)
{
int ndatums = estate->ndatums;
PLpgSQL_datum **indatums;
PLpgSQL_datum **outdatums;
char *workspace;
char *ws_next;
int i;
/* Allocate local datum-pointer array */
estate->datums = (PLpgSQL_datum **)
palloc(sizeof(PLpgSQL_datum *) * ndatums);
/*
* To reduce palloc overhead, we make a single palloc request for all the
* space needed for locally-instantiated datums.
*/
workspace = palloc(func->copiable_size);
ws_next = workspace;
/* Fill datum-pointer array, copying datums into workspace as needed */
indatums = func->datums;
outdatums = estate->datums;
for (i = 0; i < ndatums; i++)
{
PLpgSQL_datum *indatum = indatums[i];
PLpgSQL_datum *outdatum;
/* This must agree with plpgsql_finish_datums on what is copiable */
switch (indatum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
outdatum = (PLpgSQL_datum *) ws_next;
memcpy(outdatum, indatum, sizeof(PLpgSQL_var));
ws_next += MAXALIGN(sizeof(PLpgSQL_var));
break;
case PLPGSQL_DTYPE_REC:
outdatum = (PLpgSQL_datum *) ws_next;
memcpy(outdatum, indatum, sizeof(PLpgSQL_rec));
ws_next += MAXALIGN(sizeof(PLpgSQL_rec));
break;
case PLPGSQL_DTYPE_ROW:
case PLPGSQL_DTYPE_RECFIELD:
case PLPGSQL_DTYPE_ARRAYELEM:
/*
* These datum records are read-only at runtime, so no need to
* copy them (well, RECFIELD and ARRAYELEM contain cached
* data, but we'd just as soon centralize the caching anyway).
*/
outdatum = indatum;
break;
default:
elog(ERROR, "unrecognized dtype: %d", indatum->dtype);
outdatum = NULL; /* keep compiler quiet */
break;
}
outdatums[i] = outdatum;
}
Assert(ws_next == workspace + func->copiable_size);
}
/*
* If the variable has an armed "promise", compute the promised value
* and assign it to the variable.
* The assignment automatically disarms the promise.
*/
static void
plpgsql_fulfill_promise(PLpgSQL_execstate *estate,
PLpgSQL_var *var)
{
MemoryContext oldcontext;
if (var->promise == PLPGSQL_PROMISE_NONE)
return; /* nothing to do */
/*
* This will typically be invoked in a short-lived context such as the
* mcontext. We must create variable values in the estate's datum
* context. This quick-and-dirty solution risks leaking some additional
* cruft there, but since any one promise is honored at most once per
* function call, it's probably not worth being more careful.
*/
oldcontext = MemoryContextSwitchTo(estate->datum_context);
switch (var->promise)
{
case PLPGSQL_PROMISE_TG_NAME:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(estate->trigdata->tg_trigger->tgname)),
false, true);
break;
case PLPGSQL_PROMISE_TG_WHEN:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (TRIGGER_FIRED_BEFORE(estate->trigdata->tg_event))
assign_text_var(estate, var, "BEFORE");
else if (TRIGGER_FIRED_AFTER(estate->trigdata->tg_event))
assign_text_var(estate, var, "AFTER");
else if (TRIGGER_FIRED_INSTEAD(estate->trigdata->tg_event))
assign_text_var(estate, var, "INSTEAD OF");
else
elog(ERROR, "unrecognized trigger execution time: not BEFORE, AFTER, or INSTEAD OF");
break;
case PLPGSQL_PROMISE_TG_LEVEL:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (TRIGGER_FIRED_FOR_ROW(estate->trigdata->tg_event))
assign_text_var(estate, var, "ROW");
else if (TRIGGER_FIRED_FOR_STATEMENT(estate->trigdata->tg_event))
assign_text_var(estate, var, "STATEMENT");
else
elog(ERROR, "unrecognized trigger event type: not ROW or STATEMENT");
break;
case PLPGSQL_PROMISE_TG_OP:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (TRIGGER_FIRED_BY_INSERT(estate->trigdata->tg_event))
assign_text_var(estate, var, "INSERT");
else if (TRIGGER_FIRED_BY_UPDATE(estate->trigdata->tg_event))
assign_text_var(estate, var, "UPDATE");
else if (TRIGGER_FIRED_BY_DELETE(estate->trigdata->tg_event))
assign_text_var(estate, var, "DELETE");
else if (TRIGGER_FIRED_BY_TRUNCATE(estate->trigdata->tg_event))
assign_text_var(estate, var, "TRUNCATE");
else
elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, UPDATE, or TRUNCATE");
break;
case PLPGSQL_PROMISE_TG_RELID:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
ObjectIdGetDatum(estate->trigdata->tg_relation->rd_id),
false, false);
break;
case PLPGSQL_PROMISE_TG_TABLE_NAME:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(RelationGetRelationName(estate->trigdata->tg_relation))),
false, true);
break;
case PLPGSQL_PROMISE_TG_TABLE_SCHEMA:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
DirectFunctionCall1(namein,
CStringGetDatum(get_namespace_name(RelationGetNamespace(estate->trigdata->tg_relation)))),
false, true);
break;
case PLPGSQL_PROMISE_TG_NARGS:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
assign_simple_var(estate, var,
Int16GetDatum(estate->trigdata->tg_trigger->tgnargs),
false, false);
break;
case PLPGSQL_PROMISE_TG_ARGV:
if (estate->trigdata == NULL)
elog(ERROR, "trigger promise is not in a trigger function");
if (estate->trigdata->tg_trigger->tgnargs > 0)
{
/*
* For historical reasons, tg_argv[] subscripts start at zero
* not one. So we can't use construct_array().
*/
int nelems = estate->trigdata->tg_trigger->tgnargs;
Datum *elems;
int dims[1];
int lbs[1];
int i;
elems = palloc(sizeof(Datum) * nelems);
for (i = 0; i < nelems; i++)
elems[i] = CStringGetTextDatum(estate->trigdata->tg_trigger->tgargs[i]);
dims[0] = nelems;
lbs[0] = 0;
assign_simple_var(estate, var,
PointerGetDatum(construct_md_array(elems, NULL,
1, dims, lbs,
TEXTOID,
-1, false, 'i')),
false, true);
}
else
{
assign_simple_var(estate, var, (Datum) 0, true, false);
}
break;
case PLPGSQL_PROMISE_TG_EVENT:
if (estate->evtrigdata == NULL)
elog(ERROR, "event trigger promise is not in an event trigger function");
assign_text_var(estate, var, estate->evtrigdata->event);
break;
case PLPGSQL_PROMISE_TG_TAG:
if (estate->evtrigdata == NULL)
elog(ERROR, "event trigger promise is not in an event trigger function");
assign_text_var(estate, var, estate->evtrigdata->tag);
break;
default:
elog(ERROR, "unrecognized promise type: %d", var->promise);
}
MemoryContextSwitchTo(oldcontext);
}
/*
* Create a memory context for statement-lifespan variables, if we don't
* have one already. It will be a child of stmt_mcontext_parent, which is
* either the function's main context or a pushed-down outer stmt_mcontext.
*/
static MemoryContext
get_stmt_mcontext(PLpgSQL_execstate *estate)
{
if (estate->stmt_mcontext == NULL)
{
estate->stmt_mcontext =
AllocSetContextCreate(estate->stmt_mcontext_parent,
"PLpgSQL per-statement data",
ALLOCSET_DEFAULT_SIZES);
}
return estate->stmt_mcontext;
}
/*
* Push down the current stmt_mcontext so that called statements won't use it.
* This is needed by statements that have statement-lifespan data and need to
* preserve it across some inner statements. The caller should eventually do
* pop_stmt_mcontext().
*/
static void
push_stmt_mcontext(PLpgSQL_execstate *estate)
{
/* Should have done get_stmt_mcontext() first */
Assert(estate->stmt_mcontext != NULL);
/* Assert we've not messed up the stack linkage */
Assert(MemoryContextGetParent(estate->stmt_mcontext) == estate->stmt_mcontext_parent);
/* Push it down to become the parent of any nested stmt mcontext */
estate->stmt_mcontext_parent = estate->stmt_mcontext;
/* And make it not available for use directly */
estate->stmt_mcontext = NULL;
}
/*
* Undo push_stmt_mcontext(). We assume this is done just before or after
* resetting the caller's stmt_mcontext; since that action will also delete
* any child contexts, there's no need to explicitly delete whatever context
* might currently be estate->stmt_mcontext.
*/
static void
pop_stmt_mcontext(PLpgSQL_execstate *estate)
{
/* We need only pop the stack */
estate->stmt_mcontext = estate->stmt_mcontext_parent;
estate->stmt_mcontext_parent = MemoryContextGetParent(estate->stmt_mcontext);
}
/*
* Subroutine for exec_stmt_block: does any condition in the condition list
* match the current exception?
*/
static bool
exception_matches_conditions(ErrorData *edata, PLpgSQL_condition *cond)
{
for (; cond != NULL; cond = cond->next)
{
int sqlerrstate = cond->sqlerrstate;
/*
* OTHERS matches everything *except* query-canceled and
* assert-failure. If you're foolish enough, you can match those
* explicitly.
*/
if (sqlerrstate == 0)
{
if (edata->sqlerrcode != ERRCODE_QUERY_CANCELED &&
edata->sqlerrcode != ERRCODE_ASSERT_FAILURE)
return true;
}
/* Exact match? */
else if (edata->sqlerrcode == sqlerrstate)
return true;
/* Category match? */
else if (ERRCODE_IS_CATEGORY(sqlerrstate) &&
ERRCODE_TO_CATEGORY(edata->sqlerrcode) == sqlerrstate)
return true;
}
return false;
}
/* ----------
* exec_stmt_block Execute a block of statements
* ----------
*/
static int
exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block)
{
volatile int rc = -1;
int i;
/*
* First initialize all variables declared in this block
*/
estate->err_text = gettext_noop("during statement block local variable initialization");
for (i = 0; i < block->n_initvars; i++)
{
int n = block->initvarnos[i];
PLpgSQL_datum *datum = estate->datums[n];
/*
* The set of dtypes handled here must match plpgsql_add_initdatums().
*
* Note that we currently don't support promise datums within blocks,
* only at a function's outermost scope, so we needn't handle those
* here.
*/
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
/*
* Free any old value, in case re-entering block, and
* initialize to NULL
*/
assign_simple_var(estate, var, (Datum) 0, true, false);
if (var->default_val == NULL)
{
/*
* If needed, give the datatype a chance to reject
* NULLs, by assigning a NULL to the variable. We
* claim the value is of type UNKNOWN, not the var's
* datatype, else coercion will be skipped.
*/
if (var->datatype->typtype == TYPTYPE_DOMAIN)
exec_assign_value(estate,
(PLpgSQL_datum *) var,
(Datum) 0,
true,
UNKNOWNOID,
-1);
/* parser should have rejected NOT NULL */
Assert(!var->notnull);
}
else
{
exec_assign_expr(estate, (PLpgSQL_datum *) var,
var->default_val);
}
}
break;
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;
/*
* Deletion of any existing object will be handled during
* the assignments below, and in some cases it's more
* efficient for us not to get rid of it beforehand.
*/
if (rec->default_val == NULL)
{
/*
* If needed, give the datatype a chance to reject
* NULLs, by assigning a NULL to the variable.
*/
exec_move_row(estate, (PLpgSQL_variable *) rec,
NULL, NULL);
/* parser should have rejected NOT NULL */
Assert(!rec->notnull);
}
else
{
exec_assign_expr(estate, (PLpgSQL_datum *) rec,
rec->default_val);
}
}
break;
default:
elog(ERROR, "unrecognized dtype: %d", datum->dtype);
}
}
if (block->exceptions)
{
/*
* Execute the statements in the block's body inside a sub-transaction
*/
MemoryContext oldcontext = CurrentMemoryContext;
ResourceOwner oldowner = CurrentResourceOwner;
ExprContext *old_eval_econtext = estate->eval_econtext;
ErrorData *save_cur_error = estate->cur_error;
MemoryContext stmt_mcontext;
estate->err_text = gettext_noop("during statement block entry");
/*
* We will need a stmt_mcontext to hold the error data if an error
* occurs. It seems best to force it to exist before entering the
* subtransaction, so that we reduce the risk of out-of-memory during
* error recovery, and because this greatly simplifies restoring the
* stmt_mcontext stack to the correct state after an error. We can
* ameliorate the cost of this by allowing the called statements to
* use this mcontext too; so we don't push it down here.
*/
stmt_mcontext = get_stmt_mcontext(estate);
BeginInternalSubTransaction(NULL);
/* Want to run statements inside function's memory context */
MemoryContextSwitchTo(oldcontext);
PG_TRY();
{
/*
* We need to run the block's statements with a new eval_econtext
* that belongs to the current subtransaction; if we try to use
* the outer econtext then ExprContext shutdown callbacks will be
* called at the wrong times.
*/
plpgsql_create_econtext(estate);
estate->err_text = NULL;
/* Run the block's statements */
rc = exec_stmts(estate, block->body);
estate->err_text = gettext_noop("during statement block exit");
/*
* If the block ended with RETURN, we may need to copy the return
* value out of the subtransaction eval_context. We can avoid a
* physical copy if the value happens to be a R/W expanded object.
*/
if (rc == PLPGSQL_RC_RETURN &&
!estate->retisset &&
!estate->retisnull)
{
int16 resTypLen;
bool resTypByVal;
get_typlenbyval(estate->rettype, &resTypLen, &resTypByVal);
estate->retval = datumTransfer(estate->retval,
resTypByVal, resTypLen);
}
/* Commit the inner transaction, return to outer xact context */
ReleaseCurrentSubTransaction();
MemoryContextSwitchTo(oldcontext);
CurrentResourceOwner = oldowner;
/* Assert that the stmt_mcontext stack is unchanged */
Assert(stmt_mcontext == estate->stmt_mcontext);
/*
* Revert to outer eval_econtext. (The inner one was
* automatically cleaned up during subxact exit.)
*/
estate->eval_econtext = old_eval_econtext;
}
PG_CATCH();
{
ErrorData *edata;
ListCell *e;
estate->err_text = gettext_noop("during exception cleanup");
/* Save error info in our stmt_mcontext */
MemoryContextSwitchTo(stmt_mcontext);
edata = CopyErrorData();
FlushErrorState();
/* Abort the inner transaction */
RollbackAndReleaseCurrentSubTransaction();
MemoryContextSwitchTo(oldcontext);
CurrentResourceOwner = oldowner;
/*
* Set up the stmt_mcontext stack as though we had restored our
* previous state and then done push_stmt_mcontext(). The push is
* needed so that statements in the exception handler won't
* clobber the error data that's in our stmt_mcontext.
*/
estate->stmt_mcontext_parent = stmt_mcontext;
estate->stmt_mcontext = NULL;
/*
* Now we can delete any nested stmt_mcontexts that might have
* been created as children of ours. (Note: we do not immediately
* release any statement-lifespan data that might have been left
* behind in stmt_mcontext itself. We could attempt that by doing
* a MemoryContextReset on it before collecting the error data
* above, but it seems too risky to do any significant amount of
* work before collecting the error.)
*/
MemoryContextDeleteChildren(stmt_mcontext);
/* Revert to outer eval_econtext */
estate->eval_econtext = old_eval_econtext;
/*
* Must clean up the econtext too. However, any tuple table made
* in the subxact will have been thrown away by SPI during subxact
* abort, so we don't need to (and mustn't try to) free the
* eval_tuptable.
*/
estate->eval_tuptable = NULL;
exec_eval_cleanup(estate);
/* Look for a matching exception handler */
foreach(e, block->exceptions->exc_list)
{
PLpgSQL_exception *exception = (PLpgSQL_exception *) lfirst(e);
if (exception_matches_conditions(edata, exception->conditions))
{
/*
* Initialize the magic SQLSTATE and SQLERRM variables for
* the exception block; this also frees values from any
* prior use of the same exception. We needn't do this
* until we have found a matching exception.
*/
PLpgSQL_var *state_var;
PLpgSQL_var *errm_var;
state_var = (PLpgSQL_var *)
estate->datums[block->exceptions->sqlstate_varno];
errm_var = (PLpgSQL_var *)
estate->datums[block->exceptions->sqlerrm_varno];
assign_text_var(estate, state_var,
unpack_sql_state(edata->sqlerrcode));
assign_text_var(estate, errm_var, edata->message);
/*
* Also set up cur_error so the error data is accessible
* inside the handler.
*/
estate->cur_error = edata;
estate->err_text = NULL;
rc = exec_stmts(estate, exception->action);
break;
}
}
/*
* Restore previous state of cur_error, whether or not we executed
* a handler. This is needed in case an error got thrown from
* some inner block's exception handler.
*/
estate->cur_error = save_cur_error;
/* If no match found, re-throw the error */
if (e == NULL)
ReThrowError(edata);
/* Restore stmt_mcontext stack and release the error data */
pop_stmt_mcontext(estate);
MemoryContextReset(stmt_mcontext);
}
PG_END_TRY();
Assert(save_cur_error == estate->cur_error);
}
else
{
/*
* Just execute the statements in the block's body
*/
estate->err_text = NULL;
rc = exec_stmts(estate, block->body);
}
estate->err_text = NULL;
/*
* Handle the return code. This is intentionally different from
* LOOP_RC_PROCESSING(): CONTINUE never matches a block, and EXIT matches
* a block only if there is a label match.
*/
switch (rc)
{
case PLPGSQL_RC_OK:
case PLPGSQL_RC_RETURN:
case PLPGSQL_RC_CONTINUE:
return rc;
case PLPGSQL_RC_EXIT:
if (estate->exitlabel == NULL)
return PLPGSQL_RC_EXIT;
if (block->label == NULL)
return PLPGSQL_RC_EXIT;
if (strcmp(block->label, estate->exitlabel) != 0)
return PLPGSQL_RC_EXIT;
estate->exitlabel = NULL;
return PLPGSQL_RC_OK;
default:
elog(ERROR, "unrecognized rc: %d", rc);
}
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmts Iterate over a list of statements
* as long as their return code is OK
* ----------
*/
static int
exec_stmts(PLpgSQL_execstate *estate, List *stmts)
{
ListCell *s;
if (stmts == NIL)
{
/*
* Ensure we do a CHECK_FOR_INTERRUPTS() even though there is no
* statement. This prevents hangup in a tight loop if, for instance,
* there is a LOOP construct with an empty body.
*/
CHECK_FOR_INTERRUPTS();
return PLPGSQL_RC_OK;
}
foreach(s, stmts)
{
PLpgSQL_stmt *stmt = (PLpgSQL_stmt *) lfirst(s);
int rc = exec_stmt(estate, stmt);
if (rc != PLPGSQL_RC_OK)
return rc;
}
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt Distribute one statement to the statements
* type specific execution function.
* ----------
*/
static int
exec_stmt(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
{
PLpgSQL_stmt *save_estmt;
int rc = -1;
save_estmt = estate->err_stmt;
estate->err_stmt = stmt;
/* Let the plugin know that we are about to execute this statement */
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->stmt_beg)
((*plpgsql_plugin_ptr)->stmt_beg) (estate, stmt);
CHECK_FOR_INTERRUPTS();
switch (stmt->cmd_type)
{
case PLPGSQL_STMT_BLOCK:
rc = exec_stmt_block(estate, (PLpgSQL_stmt_block *) stmt);
break;
case PLPGSQL_STMT_ASSIGN:
rc = exec_stmt_assign(estate, (PLpgSQL_stmt_assign *) stmt);
break;
case PLPGSQL_STMT_PERFORM:
rc = exec_stmt_perform(estate, (PLpgSQL_stmt_perform *) stmt);
break;
case PLPGSQL_STMT_CALL:
rc = exec_stmt_call(estate, (PLpgSQL_stmt_call *) stmt);
break;
case PLPGSQL_STMT_GETDIAG:
rc = exec_stmt_getdiag(estate, (PLpgSQL_stmt_getdiag *) stmt);
break;
case PLPGSQL_STMT_IF:
rc = exec_stmt_if(estate, (PLpgSQL_stmt_if *) stmt);
break;
case PLPGSQL_STMT_CASE:
rc = exec_stmt_case(estate, (PLpgSQL_stmt_case *) stmt);
break;
case PLPGSQL_STMT_LOOP:
rc = exec_stmt_loop(estate, (PLpgSQL_stmt_loop *) stmt);
break;
case PLPGSQL_STMT_WHILE:
rc = exec_stmt_while(estate, (PLpgSQL_stmt_while *) stmt);
break;
case PLPGSQL_STMT_FORI:
rc = exec_stmt_fori(estate, (PLpgSQL_stmt_fori *) stmt);
break;
case PLPGSQL_STMT_FORS:
rc = exec_stmt_fors(estate, (PLpgSQL_stmt_fors *) stmt);
break;
case PLPGSQL_STMT_FORC:
rc = exec_stmt_forc(estate, (PLpgSQL_stmt_forc *) stmt);
break;
case PLPGSQL_STMT_FOREACH_A:
rc = exec_stmt_foreach_a(estate, (PLpgSQL_stmt_foreach_a *) stmt);
break;
case PLPGSQL_STMT_EXIT:
rc = exec_stmt_exit(estate, (PLpgSQL_stmt_exit *) stmt);
break;
case PLPGSQL_STMT_RETURN:
rc = exec_stmt_return(estate, (PLpgSQL_stmt_return *) stmt);
break;
case PLPGSQL_STMT_RETURN_NEXT:
rc = exec_stmt_return_next(estate, (PLpgSQL_stmt_return_next *) stmt);
break;
case PLPGSQL_STMT_RETURN_QUERY:
rc = exec_stmt_return_query(estate, (PLpgSQL_stmt_return_query *) stmt);
break;
case PLPGSQL_STMT_RAISE:
rc = exec_stmt_raise(estate, (PLpgSQL_stmt_raise *) stmt);
break;
case PLPGSQL_STMT_ASSERT:
rc = exec_stmt_assert(estate, (PLpgSQL_stmt_assert *) stmt);
break;
case PLPGSQL_STMT_EXECSQL:
rc = exec_stmt_execsql(estate, (PLpgSQL_stmt_execsql *) stmt);
break;
case PLPGSQL_STMT_DYNEXECUTE:
rc = exec_stmt_dynexecute(estate, (PLpgSQL_stmt_dynexecute *) stmt);
break;
case PLPGSQL_STMT_DYNFORS:
rc = exec_stmt_dynfors(estate, (PLpgSQL_stmt_dynfors *) stmt);
break;
case PLPGSQL_STMT_OPEN:
rc = exec_stmt_open(estate, (PLpgSQL_stmt_open *) stmt);
break;
case PLPGSQL_STMT_FETCH:
rc = exec_stmt_fetch(estate, (PLpgSQL_stmt_fetch *) stmt);
break;
case PLPGSQL_STMT_CLOSE:
rc = exec_stmt_close(estate, (PLpgSQL_stmt_close *) stmt);
break;
case PLPGSQL_STMT_COMMIT:
rc = exec_stmt_commit(estate, (PLpgSQL_stmt_commit *) stmt);
break;
case PLPGSQL_STMT_ROLLBACK:
rc = exec_stmt_rollback(estate, (PLpgSQL_stmt_rollback *) stmt);
break;
case PLPGSQL_STMT_SET:
rc = exec_stmt_set(estate, (PLpgSQL_stmt_set *) stmt);
break;
default:
estate->err_stmt = save_estmt;
elog(ERROR, "unrecognized cmd_type: %d", stmt->cmd_type);
}
/* Let the plugin know that we have finished executing this statement */
if (*plpgsql_plugin_ptr && (*plpgsql_plugin_ptr)->stmt_end)
((*plpgsql_plugin_ptr)->stmt_end) (estate, stmt);
estate->err_stmt = save_estmt;
return rc;
}
/* ----------
* exec_stmt_assign Evaluate an expression and
* put the result into a variable.
* ----------
*/
static int
exec_stmt_assign(PLpgSQL_execstate *estate, PLpgSQL_stmt_assign *stmt)
{
Assert(stmt->varno >= 0);
exec_assign_expr(estate, estate->datums[stmt->varno], stmt->expr);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_perform Evaluate query and discard result (but set
* FOUND depending on whether at least one row
* was returned).
* ----------
*/
static int
exec_stmt_perform(PLpgSQL_execstate *estate, PLpgSQL_stmt_perform *stmt)
{
PLpgSQL_expr *expr = stmt->expr;
(void) exec_run_select(estate, expr, 0, NULL);
exec_set_found(estate, (estate->eval_processed != 0));
exec_eval_cleanup(estate);
return PLPGSQL_RC_OK;
}
/*
* exec_stmt_call
*/
static int
exec_stmt_call(PLpgSQL_execstate *estate, PLpgSQL_stmt_call *stmt)
{
PLpgSQL_expr *expr = stmt->expr;
volatile LocalTransactionId before_lxid;
LocalTransactionId after_lxid;
volatile bool pushed_active_snap = false;
volatile int rc;
/* PG_TRY to ensure we clear the plan link, if needed, on failure */
PG_TRY();
{
SPIPlanPtr plan = expr->plan;
ParamListInfo paramLI;
if (plan == NULL)
{
/*
* Don't save the plan if not in atomic context. Otherwise,
* transaction ends would cause errors about plancache leaks.
*
* XXX This would be fixable with some plancache/resowner surgery
* elsewhere, but for now we'll just work around this here.
*/
exec_prepare_plan(estate, expr, 0, estate->atomic);
/*
* The procedure call could end transactions, which would upset
* the snapshot management in SPI_execute*, so don't let it do it.
* Instead, we set the snapshots ourselves below.
*/
plan = expr->plan;
plan->no_snapshots = true;
/*
* Force target to be recalculated whenever the plan changes, in
* case the procedure's argument list has changed.
*/
stmt->target = NULL;
}
/*
* We construct a DTYPE_ROW datum representing the plpgsql variables
* associated with the procedure's output arguments. Then we can use
* exec_move_row() to do the assignments.
*/
if (stmt->is_call && stmt->target == NULL)
{
Node *node;
FuncExpr *funcexpr;
HeapTuple func_tuple;
List *funcargs;
Oid *argtypes;
char **argnames;
char *argmodes;
MemoryContext oldcontext;
PLpgSQL_row *row;
int nfields;
int i;
ListCell *lc;
/*
* Get the parsed CallStmt, and look up the called procedure
*/
node = linitial_node(Query,
((CachedPlanSource *) linitial(plan->plancache_list))->query_list)->utilityStmt;
if (node == NULL || !IsA(node, CallStmt))
elog(ERROR, "query for CALL statement is not a CallStmt");
funcexpr = ((CallStmt *) node)->funcexpr;
func_tuple = SearchSysCache1(PROCOID,
ObjectIdGetDatum(funcexpr->funcid));
if (!HeapTupleIsValid(func_tuple))
elog(ERROR, "cache lookup failed for function %u",
funcexpr->funcid);
/*
* Extract function arguments, and expand any named-arg notation
*/
funcargs = expand_function_arguments(funcexpr->args,
funcexpr->funcresulttype,
func_tuple);
/*
* Get the argument names and modes, too
*/
get_func_arg_info(func_tuple, &argtypes, &argnames, &argmodes);
ReleaseSysCache(func_tuple);
/*
* Begin constructing row Datum
*/
oldcontext = MemoryContextSwitchTo(estate->func->fn_cxt);
row = (PLpgSQL_row *) palloc0(sizeof(PLpgSQL_row));
row->dtype = PLPGSQL_DTYPE_ROW;
row->refname = "(unnamed row)";
row->lineno = -1;
row->varnos = (int *) palloc(sizeof(int) * list_length(funcargs));
MemoryContextSwitchTo(oldcontext);
/*
* Examine procedure's argument list. Each output arg position
* should be an unadorned plpgsql variable (Datum), which we can
* insert into the row Datum.
*/
nfields = 0;
i = 0;
foreach(lc, funcargs)
{
Node *n = lfirst(lc);
if (argmodes &&
(argmodes[i] == PROARGMODE_INOUT ||
argmodes[i] == PROARGMODE_OUT))
{
if (IsA(n, Param))
{
Param *param = (Param *) n;
/* paramid is offset by 1 (see make_datum_param()) */
row->varnos[nfields++] = param->paramid - 1;
}
else
{
/* report error using parameter name, if available */
if (argnames && argnames[i] && argnames[i][0])
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("procedure parameter \"%s\" is an output parameter but corresponding argument is not writable",
argnames[i])));
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("procedure parameter %d is an output parameter but corresponding argument is not writable",
i + 1)));
}
}
i++;
}
row->nfields = nfields;
stmt->target = (PLpgSQL_variable *) row;
}
paramLI = setup_param_list(estate, expr);
before_lxid = MyProc->lxid;
/*
* Set snapshot only for non-read-only procedures, similar to SPI
* behavior.
*/
if (!estate->readonly_func)
{
PushActiveSnapshot(GetTransactionSnapshot());
pushed_active_snap = true;
}
rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
estate->readonly_func, 0);
}
PG_CATCH();
{
/*
* If we aren't saving the plan, unset the pointer. Note that it
* could have been unset already, in case of a recursive call.
*/
if (expr->plan && !expr->plan->saved)
expr->plan = NULL;
PG_RE_THROW();
}
PG_END_TRY();
if (expr->plan && !expr->plan->saved)
expr->plan = NULL;
if (rc < 0)
elog(ERROR, "SPI_execute_plan_with_paramlist failed executing query \"%s\": %s",
expr->query, SPI_result_code_string(rc));
after_lxid = MyProc->lxid;
if (before_lxid == after_lxid)
{
/*
* If we are still in the same transaction after the call, pop the
* snapshot that we might have pushed. (If it's a new transaction,
* then all the snapshots are gone already.)
*/
if (pushed_active_snap)
PopActiveSnapshot();
}
else
{
/*
* If we are in a new transaction after the call, we need to reset
* some internal state.
*/
estate->simple_eval_estate = NULL;
plpgsql_create_econtext(estate);
}
/*
* Check result rowcount; if there's one row, assign procedure's output
* values back to the appropriate variables.
*/
if (SPI_processed == 1)
{
SPITupleTable *tuptab = SPI_tuptable;
if (!stmt->target)
elog(ERROR, "DO statement returned a row");
exec_move_row(estate, stmt->target, tuptab->vals[0], tuptab->tupdesc);
}
else if (SPI_processed > 1)
elog(ERROR, "procedure call returned more than one row");
exec_eval_cleanup(estate);
SPI_freetuptable(SPI_tuptable);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_getdiag Put internal PG information into
* specified variables.
* ----------
*/
static int
exec_stmt_getdiag(PLpgSQL_execstate *estate, PLpgSQL_stmt_getdiag *stmt)
{
ListCell *lc;
/*
* GET STACKED DIAGNOSTICS is only valid inside an exception handler.
*
* Note: we trust the grammar to have disallowed the relevant item kinds
* if not is_stacked, otherwise we'd dump core below.
*/
if (stmt->is_stacked && estate->cur_error == NULL)
ereport(ERROR,
(errcode(ERRCODE_STACKED_DIAGNOSTICS_ACCESSED_WITHOUT_ACTIVE_HANDLER),
errmsg("GET STACKED DIAGNOSTICS cannot be used outside an exception handler")));
foreach(lc, stmt->diag_items)
{
PLpgSQL_diag_item *diag_item = (PLpgSQL_diag_item *) lfirst(lc);
PLpgSQL_datum *var = estate->datums[diag_item->target];
switch (diag_item->kind)
{
case PLPGSQL_GETDIAG_ROW_COUNT:
exec_assign_value(estate, var,
UInt64GetDatum(estate->eval_processed),
false, INT8OID, -1);
break;
case PLPGSQL_GETDIAG_ERROR_CONTEXT:
exec_assign_c_string(estate, var,
estate->cur_error->context);
break;
case PLPGSQL_GETDIAG_ERROR_DETAIL:
exec_assign_c_string(estate, var,
estate->cur_error->detail);
break;
case PLPGSQL_GETDIAG_ERROR_HINT:
exec_assign_c_string(estate, var,
estate->cur_error->hint);
break;
case PLPGSQL_GETDIAG_RETURNED_SQLSTATE:
exec_assign_c_string(estate, var,
unpack_sql_state(estate->cur_error->sqlerrcode));
break;
case PLPGSQL_GETDIAG_COLUMN_NAME:
exec_assign_c_string(estate, var,
estate->cur_error->column_name);
break;
case PLPGSQL_GETDIAG_CONSTRAINT_NAME:
exec_assign_c_string(estate, var,
estate->cur_error->constraint_name);
break;
case PLPGSQL_GETDIAG_DATATYPE_NAME:
exec_assign_c_string(estate, var,
estate->cur_error->datatype_name);
break;
case PLPGSQL_GETDIAG_MESSAGE_TEXT:
exec_assign_c_string(estate, var,
estate->cur_error->message);
break;
case PLPGSQL_GETDIAG_TABLE_NAME:
exec_assign_c_string(estate, var,
estate->cur_error->table_name);
break;
case PLPGSQL_GETDIAG_SCHEMA_NAME:
exec_assign_c_string(estate, var,
estate->cur_error->schema_name);
break;
case PLPGSQL_GETDIAG_CONTEXT:
{
char *contextstackstr;
MemoryContext oldcontext;
/* Use eval_mcontext for short-lived string */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
contextstackstr = GetErrorContextStack();
MemoryContextSwitchTo(oldcontext);
exec_assign_c_string(estate, var, contextstackstr);
}
break;
default:
elog(ERROR, "unrecognized diagnostic item kind: %d",
diag_item->kind);
}
}
exec_eval_cleanup(estate);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_if Evaluate a bool expression and
* execute the true or false body
* conditionally.
* ----------
*/
static int
exec_stmt_if(PLpgSQL_execstate *estate, PLpgSQL_stmt_if *stmt)
{
bool value;
bool isnull;
ListCell *lc;
value = exec_eval_boolean(estate, stmt->cond, &isnull);
exec_eval_cleanup(estate);
if (!isnull && value)
return exec_stmts(estate, stmt->then_body);
foreach(lc, stmt->elsif_list)
{
PLpgSQL_if_elsif *elif = (PLpgSQL_if_elsif *) lfirst(lc);
value = exec_eval_boolean(estate, elif->cond, &isnull);
exec_eval_cleanup(estate);
if (!isnull && value)
return exec_stmts(estate, elif->stmts);
}
return exec_stmts(estate, stmt->else_body);
}
/*-----------
* exec_stmt_case
*-----------
*/
static int
exec_stmt_case(PLpgSQL_execstate *estate, PLpgSQL_stmt_case *stmt)
{
PLpgSQL_var *t_var = NULL;
bool isnull;
ListCell *l;
if (stmt->t_expr != NULL)
{
/* simple case */
Datum t_val;
Oid t_typoid;
int32 t_typmod;
t_val = exec_eval_expr(estate, stmt->t_expr,
&isnull, &t_typoid, &t_typmod);
t_var = (PLpgSQL_var *) estate->datums[stmt->t_varno];
/*
* When expected datatype is different from real, change it. Note that
* what we're modifying here is an execution copy of the datum, so
* this doesn't affect the originally stored function parse tree. (In
* theory, if the expression datatype keeps changing during execution,
* this could cause a function-lifespan memory leak. Doesn't seem
* worth worrying about though.)
*/
if (t_var->datatype->typoid != t_typoid ||
t_var->datatype->atttypmod != t_typmod)
t_var->datatype = plpgsql_build_datatype(t_typoid,
t_typmod,
estate->func->fn_input_collation);
/* now we can assign to the variable */
exec_assign_value(estate,
(PLpgSQL_datum *) t_var,
t_val,
isnull,
t_typoid,
t_typmod);
exec_eval_cleanup(estate);
}
/* Now search for a successful WHEN clause */
foreach(l, stmt->case_when_list)
{
PLpgSQL_case_when *cwt = (PLpgSQL_case_when *) lfirst(l);
bool value;
value = exec_eval_boolean(estate, cwt->expr, &isnull);
exec_eval_cleanup(estate);
if (!isnull && value)
{
/* Found it */
/* We can now discard any value we had for the temp variable */
if (t_var != NULL)
assign_simple_var(estate, t_var, (Datum) 0, true, false);
/* Evaluate the statement(s), and we're done */
return exec_stmts(estate, cwt->stmts);
}
}
/* We can now discard any value we had for the temp variable */
if (t_var != NULL)
assign_simple_var(estate, t_var, (Datum) 0, true, false);
/* SQL2003 mandates this error if there was no ELSE clause */
if (!stmt->have_else)
ereport(ERROR,
(errcode(ERRCODE_CASE_NOT_FOUND),
errmsg("case not found"),
errhint("CASE statement is missing ELSE part.")));
/* Evaluate the ELSE statements, and we're done */
return exec_stmts(estate, stmt->else_stmts);
}
/* ----------
* exec_stmt_loop Loop over statements until
* an exit occurs.
* ----------
*/
static int
exec_stmt_loop(PLpgSQL_execstate *estate, PLpgSQL_stmt_loop *stmt)
{
int rc = PLPGSQL_RC_OK;
for (;;)
{
rc = exec_stmts(estate, stmt->body);
LOOP_RC_PROCESSING(stmt->label, break);
}
return rc;
}
/* ----------
* exec_stmt_while Loop over statements as long
* as an expression evaluates to
* true or an exit occurs.
* ----------
*/
static int
exec_stmt_while(PLpgSQL_execstate *estate, PLpgSQL_stmt_while *stmt)
{
int rc = PLPGSQL_RC_OK;
for (;;)
{
bool value;
bool isnull;
value = exec_eval_boolean(estate, stmt->cond, &isnull);
exec_eval_cleanup(estate);
if (isnull || !value)
break;
rc = exec_stmts(estate, stmt->body);
LOOP_RC_PROCESSING(stmt->label, break);
}
return rc;
}
/* ----------
* exec_stmt_fori Iterate an integer variable
* from a lower to an upper value
* incrementing or decrementing by the BY value
* ----------
*/
static int
exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
{
PLpgSQL_var *var;
Datum value;
bool isnull;
Oid valtype;
int32 valtypmod;
int32 loop_value;
int32 end_value;
int32 step_value;
bool found = false;
int rc = PLPGSQL_RC_OK;
var = (PLpgSQL_var *) (estate->datums[stmt->var->dno]);
/*
* Get the value of the lower bound
*/
value = exec_eval_expr(estate, stmt->lower,
&isnull, &valtype, &valtypmod);
value = exec_cast_value(estate, value, &isnull,
valtype, valtypmod,
var->datatype->typoid,
var->datatype->atttypmod);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("lower bound of FOR loop cannot be null")));
loop_value = DatumGetInt32(value);
exec_eval_cleanup(estate);
/*
* Get the value of the upper bound
*/
value = exec_eval_expr(estate, stmt->upper,
&isnull, &valtype, &valtypmod);
value = exec_cast_value(estate, value, &isnull,
valtype, valtypmod,
var->datatype->typoid,
var->datatype->atttypmod);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("upper bound of FOR loop cannot be null")));
end_value = DatumGetInt32(value);
exec_eval_cleanup(estate);
/*
* Get the step value
*/
if (stmt->step)
{
value = exec_eval_expr(estate, stmt->step,
&isnull, &valtype, &valtypmod);
value = exec_cast_value(estate, value, &isnull,
valtype, valtypmod,
var->datatype->typoid,
var->datatype->atttypmod);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("BY value of FOR loop cannot be null")));
step_value = DatumGetInt32(value);
exec_eval_cleanup(estate);
if (step_value <= 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("BY value of FOR loop must be greater than zero")));
}
else
step_value = 1;
/*
* Now do the loop
*/
for (;;)
{
/*
* Check against upper bound
*/
if (stmt->reverse)
{
if (loop_value < end_value)
break;
}
else
{
if (loop_value > end_value)
break;
}
found = true; /* looped at least once */
/*
* Assign current value to loop var
*/
assign_simple_var(estate, var, Int32GetDatum(loop_value), false, false);
/*
* Execute the statements
*/
rc = exec_stmts(estate, stmt->body);
LOOP_RC_PROCESSING(stmt->label, break);
/*
* Increase/decrease loop value, unless it would overflow, in which
* case exit the loop.
*/
if (stmt->reverse)
{
if (loop_value < (PG_INT32_MIN + step_value))
break;
loop_value -= step_value;
}
else
{
if (loop_value > (PG_INT32_MAX - step_value))
break;
loop_value += step_value;
}
}
/*
* Set the FOUND variable to indicate the result of executing the loop
* (namely, whether we looped one or more times). This must be set here so
* that it does not interfere with the value of the FOUND variable inside
* the loop processing itself.
*/
exec_set_found(estate, found);
return rc;
}
/* ----------
* exec_stmt_fors Execute a query, assign each
* tuple to a record or row and
* execute a group of statements
* for it.
* ----------
*/
static int
exec_stmt_fors(PLpgSQL_execstate *estate, PLpgSQL_stmt_fors *stmt)
{
Portal portal;
int rc;
/*
* Open the implicit cursor for the statement using exec_run_select
*/
exec_run_select(estate, stmt->query, 0, &portal);
/*
* Execute the loop
*/
rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, true);
/*
* Close the implicit cursor
*/
SPI_cursor_close(portal);
return rc;
}
/* ----------
* exec_stmt_forc Execute a loop for each row from a cursor.
* ----------
*/
static int
exec_stmt_forc(PLpgSQL_execstate *estate, PLpgSQL_stmt_forc *stmt)
{
PLpgSQL_var *curvar;
MemoryContext stmt_mcontext = NULL;
char *curname = NULL;
PLpgSQL_expr *query;
ParamListInfo paramLI;
Portal portal;
int rc;
/* ----------
* Get the cursor variable and if it has an assigned name, check
* that it's not in use currently.
* ----------
*/
curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
if (!curvar->isnull)
{
MemoryContext oldcontext;
/* We only need stmt_mcontext to hold the cursor name string */
stmt_mcontext = get_stmt_mcontext(estate);
oldcontext = MemoryContextSwitchTo(stmt_mcontext);
curname = TextDatumGetCString(curvar->value);
MemoryContextSwitchTo(oldcontext);
if (SPI_cursor_find(curname) != NULL)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_CURSOR),
errmsg("cursor \"%s\" already in use", curname)));
}
/* ----------
* Open the cursor just like an OPEN command
*
* Note: parser should already have checked that statement supplies
* args iff cursor needs them, but we check again to be safe.
* ----------
*/
if (stmt->argquery != NULL)
{
/* ----------
* OPEN CURSOR with args. We fake a SELECT ... INTO ...
* statement to evaluate the args and put 'em into the
* internal row.
* ----------
*/
PLpgSQL_stmt_execsql set_args;
if (curvar->cursor_explicit_argrow < 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("arguments given for cursor without arguments")));
memset(&set_args, 0, sizeof(set_args));
set_args.cmd_type = PLPGSQL_STMT_EXECSQL;
set_args.lineno = stmt->lineno;
set_args.sqlstmt = stmt->argquery;
set_args.into = true;
/* XXX historically this has not been STRICT */
set_args.target = (PLpgSQL_variable *)
(estate->datums[curvar->cursor_explicit_argrow]);
if (exec_stmt_execsql(estate, &set_args) != PLPGSQL_RC_OK)
elog(ERROR, "open cursor failed during argument processing");
}
else
{
if (curvar->cursor_explicit_argrow >= 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("arguments required for cursor")));
}
query = curvar->cursor_explicit_expr;
Assert(query);
if (query->plan == NULL)
exec_prepare_plan(estate, query, curvar->cursor_options | CURSOR_OPT_UPDATABLE, true);
/*
* Set up ParamListInfo for this query
*/
paramLI = setup_param_list(estate, query);
/*
* Open the cursor (the paramlist will get copied into the portal)
*/
portal = SPI_cursor_open_with_paramlist(curname, query->plan,
paramLI,
estate->readonly_func);
if (portal == NULL)
elog(ERROR, "could not open cursor: %s",
SPI_result_code_string(SPI_result));
/*
* If cursor variable was NULL, store the generated portal name in it
*/
if (curname == NULL)
assign_text_var(estate, curvar, portal->name);
/*
* Clean up before entering exec_for_query
*/
exec_eval_cleanup(estate);
if (stmt_mcontext)
MemoryContextReset(stmt_mcontext);
/*
* Execute the loop. We can't prefetch because the cursor is accessible
* to the user, for instance via UPDATE WHERE CURRENT OF within the loop.
*/
rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, false);
/* ----------
* Close portal, and restore cursor variable if it was initially NULL.
* ----------
*/
SPI_cursor_close(portal);
if (curname == NULL)
assign_simple_var(estate, curvar, (Datum) 0, true, false);
return rc;
}
/* ----------
* exec_stmt_foreach_a Loop over elements or slices of an array
*
* When looping over elements, the loop variable is the same type that the
* array stores (eg: integer), when looping through slices, the loop variable
* is an array of size and dimensions to match the size of the slice.
* ----------
*/
static int
exec_stmt_foreach_a(PLpgSQL_execstate *estate, PLpgSQL_stmt_foreach_a *stmt)
{
ArrayType *arr;
Oid arrtype;
int32 arrtypmod;
PLpgSQL_datum *loop_var;
Oid loop_var_elem_type;
bool found = false;
int rc = PLPGSQL_RC_OK;
MemoryContext stmt_mcontext;
MemoryContext oldcontext;
ArrayIterator array_iterator;
Oid iterator_result_type;
int32 iterator_result_typmod;
Datum value;
bool isnull;
/* get the value of the array expression */
value = exec_eval_expr(estate, stmt->expr, &isnull, &arrtype, &arrtypmod);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("FOREACH expression must not be null")));
/*
* Do as much as possible of the code below in stmt_mcontext, to avoid any
* leaks from called subroutines. We need a private stmt_mcontext since
* we'll be calling arbitrary statement code.
*/
stmt_mcontext = get_stmt_mcontext(estate);
push_stmt_mcontext(estate);
oldcontext = MemoryContextSwitchTo(stmt_mcontext);
/* check the type of the expression - must be an array */
if (!OidIsValid(get_element_type(arrtype)))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("FOREACH expression must yield an array, not type %s",
format_type_be(arrtype))));
/*
* We must copy the array into stmt_mcontext, else it will disappear in
* exec_eval_cleanup. This is annoying, but cleanup will certainly happen
* while running the loop body, so we have little choice.
*/
arr = DatumGetArrayTypePCopy(value);
/* Clean up any leftover temporary memory */
exec_eval_cleanup(estate);
/* Slice dimension must be less than or equal to array dimension */
if (stmt->slice < 0 || stmt->slice > ARR_NDIM(arr))
ereport(ERROR,
(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
errmsg("slice dimension (%d) is out of the valid range 0..%d",
stmt->slice, ARR_NDIM(arr))));
/* Set up the loop variable and see if it is of an array type */
loop_var = estate->datums[stmt->varno];
if (loop_var->dtype == PLPGSQL_DTYPE_REC ||
loop_var->dtype == PLPGSQL_DTYPE_ROW)
{
/*
* Record/row variable is certainly not of array type, and might not
* be initialized at all yet, so don't try to get its type
*/
loop_var_elem_type = InvalidOid;
}
else
loop_var_elem_type = get_element_type(plpgsql_exec_get_datum_type(estate,
loop_var));
/*
* Sanity-check the loop variable type. We don't try very hard here, and
* should not be too picky since it's possible that exec_assign_value can
* coerce values of different types. But it seems worthwhile to complain
* if the array-ness of the loop variable is not right.
*/
if (stmt->slice > 0 && loop_var_elem_type == InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("FOREACH ... SLICE loop variable must be of an array type")));
if (stmt->slice == 0 && loop_var_elem_type != InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("FOREACH loop variable must not be of an array type")));
/* Create an iterator to step through the array */
array_iterator = array_create_iterator(arr, stmt->slice, NULL);
/* Identify iterator result type */
if (stmt->slice > 0)
{
/* When slicing, nominal type of result is same as array type */
iterator_result_type = arrtype;
iterator_result_typmod = arrtypmod;
}
else
{
/* Without slicing, results are individual array elements */
iterator_result_type = ARR_ELEMTYPE(arr);
iterator_result_typmod = arrtypmod;
}
/* Iterate over the array elements or slices */
while (array_iterate(array_iterator, &value, &isnull))
{
found = true; /* looped at least once */
/* exec_assign_value and exec_stmts must run in the main context */
MemoryContextSwitchTo(oldcontext);
/* Assign current element/slice to the loop variable */
exec_assign_value(estate, loop_var, value, isnull,
iterator_result_type, iterator_result_typmod);
/* In slice case, value is temporary; must free it to avoid leakage */
if (stmt->slice > 0)
pfree(DatumGetPointer(value));
/*
* Execute the statements
*/
rc = exec_stmts(estate, stmt->body);
LOOP_RC_PROCESSING(stmt->label, break);
MemoryContextSwitchTo(stmt_mcontext);
}
/* Restore memory context state */
MemoryContextSwitchTo(oldcontext);
pop_stmt_mcontext(estate);
/* Release temporary memory, including the array value */
MemoryContextReset(stmt_mcontext);
/*
* Set the FOUND variable to indicate the result of executing the loop
* (namely, whether we looped one or more times). This must be set here so
* that it does not interfere with the value of the FOUND variable inside
* the loop processing itself.
*/
exec_set_found(estate, found);
return rc;
}
/* ----------
* exec_stmt_exit Implements EXIT and CONTINUE
*
* This begins the process of exiting / restarting a loop.
* ----------
*/
static int
exec_stmt_exit(PLpgSQL_execstate *estate, PLpgSQL_stmt_exit *stmt)
{
/*
* If the exit / continue has a condition, evaluate it
*/
if (stmt->cond != NULL)
{
bool value;
bool isnull;
value = exec_eval_boolean(estate, stmt->cond, &isnull);
exec_eval_cleanup(estate);
if (isnull || value == false)
return PLPGSQL_RC_OK;
}
estate->exitlabel = stmt->label;
if (stmt->is_exit)
return PLPGSQL_RC_EXIT;
else
return PLPGSQL_RC_CONTINUE;
}
/* ----------
* exec_stmt_return Evaluate an expression and start
* returning from the function.
*
* Note: The result may be in the eval_mcontext. Therefore, we must not
* do exec_eval_cleanup while unwinding the control stack.
* ----------
*/
static int
exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
{
/*
* If processing a set-returning PL/pgSQL function, the final RETURN
* indicates that the function is finished producing tuples. The rest of
* the work will be done at the top level.
*/
if (estate->retisset)
return PLPGSQL_RC_RETURN;
/* initialize for null result */
estate->retval = (Datum) 0;
estate->retisnull = true;
estate->rettype = InvalidOid;
/*
* Special case path when the RETURN expression is a simple variable
* reference; in particular, this path is always taken in functions with
* one or more OUT parameters.
*
* This special case is especially efficient for returning variables that
* have R/W expanded values: we can put the R/W pointer directly into
* estate->retval, leading to transferring the value to the caller's
* context cheaply. If we went through exec_eval_expr we'd end up with a
* R/O pointer. It's okay to skip MakeExpandedObjectReadOnly here since
* we know we won't need the variable's value within the function anymore.
*/
if (stmt->retvarno >= 0)
{
PLpgSQL_datum *retvar = estate->datums[stmt->retvarno];
switch (retvar->dtype)
{
case PLPGSQL_DTYPE_PROMISE:
/* fulfill promise if needed, then handle like regular var */
plpgsql_fulfill_promise(estate, (PLpgSQL_var *) retvar);
/* FALL THRU */
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) retvar;
estate->retval = var->value;
estate->retisnull = var->isnull;
estate->rettype = var->datatype->typoid;
/*
* A PLpgSQL_var could not be of composite type, so
* conversion must fail if retistuple. We throw a custom
* error mainly for consistency with historical behavior.
* For the same reason, we don't throw error if the result
* is NULL. (Note that plpgsql_exec_trigger assumes that
* any non-null result has been verified to be composite.)
*/
if (estate->retistuple && !estate->retisnull)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot return non-composite value from function returning composite type")));
}
break;
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) retvar;
/* If record is empty, we return NULL not a row of nulls */
if (rec->erh && !ExpandedRecordIsEmpty(rec->erh))
{
estate->retval = ExpandedRecordGetDatum(rec->erh);
estate->retisnull = false;
estate->rettype = rec->rectypeid;
}
}
break;
case PLPGSQL_DTYPE_ROW:
{
PLpgSQL_row *row = (PLpgSQL_row *) retvar;
int32 rettypmod;
/* We get here if there are multiple OUT parameters */
exec_eval_datum(estate,
(PLpgSQL_datum *) row,
&estate->rettype,
&rettypmod,
&estate->retval,
&estate->retisnull);
}
break;
default:
elog(ERROR, "unrecognized dtype: %d", retvar->dtype);
}
return PLPGSQL_RC_RETURN;
}
if (stmt->expr != NULL)
{
int32 rettypmod;
estate->retval = exec_eval_expr(estate, stmt->expr,
&(estate->retisnull),
&(estate->rettype),
&rettypmod);
/*
* As in the DTYPE_VAR case above, throw a custom error if a non-null,
* non-composite value is returned in a function returning tuple.
*/
if (estate->retistuple && !estate->retisnull &&
!type_is_rowtype(estate->rettype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot return non-composite value from function returning composite type")));
return PLPGSQL_RC_RETURN;
}
/*
* Special hack for function returning VOID: instead of NULL, return a
* non-null VOID value. This is of dubious importance but is kept for
* backwards compatibility. We don't do it for procedures, though.
*/
if (estate->fn_rettype == VOIDOID &&
estate->func->fn_prokind != PROKIND_PROCEDURE)
{
estate->retval = (Datum) 0;
estate->retisnull = false;
estate->rettype = VOIDOID;
}
return PLPGSQL_RC_RETURN;
}
/* ----------
* exec_stmt_return_next Evaluate an expression and add it to the
* list of tuples returned by the current
* SRF.
* ----------
*/
static int
exec_stmt_return_next(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_next *stmt)
{
TupleDesc tupdesc;
int natts;
HeapTuple tuple;
MemoryContext oldcontext;
if (!estate->retisset)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cannot use RETURN NEXT in a non-SETOF function")));
if (estate->tuple_store == NULL)
exec_init_tuple_store(estate);
/* tuple_store_desc will be filled by exec_init_tuple_store */
tupdesc = estate->tuple_store_desc;
natts = tupdesc->natts;
/*
* Special case path when the RETURN NEXT expression is a simple variable
* reference; in particular, this path is always taken in functions with
* one or more OUT parameters.
*
* Unlike exec_statement_return, there's no special win here for R/W
* expanded values, since they'll have to get flattened to go into the
* tuplestore. Indeed, we'd better make them R/O to avoid any risk of the
* casting step changing them in-place.
*/
if (stmt->retvarno >= 0)
{
PLpgSQL_datum *retvar = estate->datums[stmt->retvarno];
switch (retvar->dtype)
{
case PLPGSQL_DTYPE_PROMISE:
/* fulfill promise if needed, then handle like regular var */
plpgsql_fulfill_promise(estate, (PLpgSQL_var *) retvar);
/* FALL THRU */
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) retvar;
Datum retval = var->value;
bool isNull = var->isnull;
Form_pg_attribute attr = TupleDescAttr(tupdesc, 0);
if (natts != 1)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("wrong result type supplied in RETURN NEXT")));
/* let's be very paranoid about the cast step */
retval = MakeExpandedObjectReadOnly(retval,
isNull,
var->datatype->typlen);
/* coerce type if needed */
retval = exec_cast_value(estate,
retval,
&isNull,
var->datatype->typoid,
var->datatype->atttypmod,
attr->atttypid,
attr->atttypmod);
tuplestore_putvalues(estate->tuple_store, tupdesc,
&retval, &isNull);
}
break;
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) retvar;
TupleDesc rec_tupdesc;
TupleConversionMap *tupmap;
/* If rec is null, try to convert it to a row of nulls */
if (rec->erh == NULL)
instantiate_empty_record_variable(estate, rec);
if (ExpandedRecordIsEmpty(rec->erh))
deconstruct_expanded_record(rec->erh);
/* Use eval_mcontext for tuple conversion work */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
rec_tupdesc = expanded_record_get_tupdesc(rec->erh);
tupmap = convert_tuples_by_position(rec_tupdesc,
tupdesc,
gettext_noop("wrong record type supplied in RETURN NEXT"));
tuple = expanded_record_get_tuple(rec->erh);
if (tupmap)
tuple = execute_attr_map_tuple(tuple, tupmap);
tuplestore_puttuple(estate->tuple_store, tuple);
MemoryContextSwitchTo(oldcontext);
}
break;
case PLPGSQL_DTYPE_ROW:
{
PLpgSQL_row *row = (PLpgSQL_row *) retvar;
/* We get here if there are multiple OUT parameters */
/* Use eval_mcontext for tuple conversion work */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
tuple = make_tuple_from_row(estate, row, tupdesc);
if (tuple == NULL) /* should not happen */
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("wrong record type supplied in RETURN NEXT")));
tuplestore_puttuple(estate->tuple_store, tuple);
MemoryContextSwitchTo(oldcontext);
}
break;
default:
elog(ERROR, "unrecognized dtype: %d", retvar->dtype);
break;
}
}
else if (stmt->expr)
{
Datum retval;
bool isNull;
Oid rettype;
int32 rettypmod;
retval = exec_eval_expr(estate,
stmt->expr,
&isNull,
&rettype,
&rettypmod);
if (estate->retistuple)
{
/* Expression should be of RECORD or composite type */
if (!isNull)
{
HeapTupleData tmptup;
TupleDesc retvaldesc;
TupleConversionMap *tupmap;
if (!type_is_rowtype(rettype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot return non-composite value from function returning composite type")));
/* Use eval_mcontext for tuple conversion work */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
retvaldesc = deconstruct_composite_datum(retval, &tmptup);
tuple = &tmptup;
tupmap = convert_tuples_by_position(retvaldesc, tupdesc,
gettext_noop("returned record type does not match expected record type"));
if (tupmap)
tuple = execute_attr_map_tuple(tuple, tupmap);
tuplestore_puttuple(estate->tuple_store, tuple);
ReleaseTupleDesc(retvaldesc);
MemoryContextSwitchTo(oldcontext);
}
else
{
/* Composite NULL --- store a row of nulls */
Datum *nulldatums;
bool *nullflags;
nulldatums = (Datum *)
eval_mcontext_alloc0(estate, natts * sizeof(Datum));
nullflags = (bool *)
eval_mcontext_alloc(estate, natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(estate->tuple_store, tupdesc,
nulldatums, nullflags);
}
}
else
{
Form_pg_attribute attr = TupleDescAttr(tupdesc, 0);
/* Simple scalar result */
if (natts != 1)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("wrong result type supplied in RETURN NEXT")));
/* coerce type if needed */
retval = exec_cast_value(estate,
retval,
&isNull,
rettype,
rettypmod,
attr->atttypid,
attr->atttypmod);
tuplestore_putvalues(estate->tuple_store, tupdesc,
&retval, &isNull);
}
}
else
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("RETURN NEXT must have a parameter")));
}
exec_eval_cleanup(estate);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_return_query Evaluate a query and add it to the
* list of tuples returned by the current
* SRF.
* ----------
*/
static int
exec_stmt_return_query(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_query *stmt)
{
Portal portal;
uint64 processed = 0;
TupleConversionMap *tupmap;
MemoryContext oldcontext;
if (!estate->retisset)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cannot use RETURN QUERY in a non-SETOF function")));
if (estate->tuple_store == NULL)
exec_init_tuple_store(estate);
if (stmt->query != NULL)
{
/* static query */
exec_run_select(estate, stmt->query, 0, &portal);
}
else
{
/* RETURN QUERY EXECUTE */
Assert(stmt->dynquery != NULL);
portal = exec_dynquery_with_params(estate, stmt->dynquery,
stmt->params, NULL,
0);
}
/* Use eval_mcontext for tuple conversion work */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
tupmap = convert_tuples_by_position(portal->tupDesc,
estate->tuple_store_desc,
gettext_noop("structure of query does not match function result type"));
while (true)
{
uint64 i;
SPI_cursor_fetch(portal, true, 50);
/* SPI will have changed CurrentMemoryContext */
MemoryContextSwitchTo(get_eval_mcontext(estate));
if (SPI_processed == 0)
break;
for (i = 0; i < SPI_processed; i++)
{
HeapTuple tuple = SPI_tuptable->vals[i];
if (tupmap)
tuple = execute_attr_map_tuple(tuple, tupmap);
tuplestore_puttuple(estate->tuple_store, tuple);
if (tupmap)
heap_freetuple(tuple);
processed++;
}
SPI_freetuptable(SPI_tuptable);
}
SPI_freetuptable(SPI_tuptable);
SPI_cursor_close(portal);
MemoryContextSwitchTo(oldcontext);
exec_eval_cleanup(estate);
estate->eval_processed = processed;
exec_set_found(estate, processed != 0);
return PLPGSQL_RC_OK;
}
static void
exec_init_tuple_store(PLpgSQL_execstate *estate)
{
ReturnSetInfo *rsi = estate->rsi;
MemoryContext oldcxt;
ResourceOwner oldowner;
/*
* Check caller can handle a set result in the way we want
*/
if (!rsi || !IsA(rsi, ReturnSetInfo) ||
(rsi->allowedModes & SFRM_Materialize) == 0 ||
rsi->expectedDesc == NULL)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
/*
* Switch to the right memory context and resource owner for storing the
* tuplestore for return set. If we're within a subtransaction opened for
* an exception-block, for example, we must still create the tuplestore in
* the resource owner that was active when this function was entered, and
* not in the subtransaction resource owner.
*/
oldcxt = MemoryContextSwitchTo(estate->tuple_store_cxt);
oldowner = CurrentResourceOwner;
CurrentResourceOwner = estate->tuple_store_owner;
estate->tuple_store =
tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
false, work_mem);
CurrentResourceOwner = oldowner;
MemoryContextSwitchTo(oldcxt);
estate->tuple_store_desc = rsi->expectedDesc;
}
#define SET_RAISE_OPTION_TEXT(opt, name) \
do { \
if (opt) \
ereport(ERROR, \
(errcode(ERRCODE_SYNTAX_ERROR), \
errmsg("RAISE option already specified: %s", \
name))); \
opt = MemoryContextStrdup(stmt_mcontext, extval); \
} while (0)
/* ----------
* exec_stmt_raise Build a message and throw it with elog()
* ----------
*/
static int
exec_stmt_raise(PLpgSQL_execstate *estate, PLpgSQL_stmt_raise *stmt)
{
int err_code = 0;
char *condname = NULL;
char *err_message = NULL;
char *err_detail = NULL;
char *err_hint = NULL;
char *err_column = NULL;
char *err_constraint = NULL;
char *err_datatype = NULL;
char *err_table = NULL;
char *err_schema = NULL;
MemoryContext stmt_mcontext;
ListCell *lc;
/* RAISE with no parameters: re-throw current exception */
if (stmt->condname == NULL && stmt->message == NULL &&
stmt->options == NIL)
{
if (estate->cur_error != NULL)
ReThrowError(estate->cur_error);
/* oops, we're not inside a handler */
ereport(ERROR,
(errcode(ERRCODE_STACKED_DIAGNOSTICS_ACCESSED_WITHOUT_ACTIVE_HANDLER),
errmsg("RAISE without parameters cannot be used outside an exception handler")));
}
/* We'll need to accumulate the various strings in stmt_mcontext */
stmt_mcontext = get_stmt_mcontext(estate);
if (stmt->condname)
{
err_code = plpgsql_recognize_err_condition(stmt->condname, true);
condname = MemoryContextStrdup(stmt_mcontext, stmt->condname);
}
if (stmt->message)
{
StringInfoData ds;
ListCell *current_param;
char *cp;
MemoryContext oldcontext;
/* build string in stmt_mcontext */
oldcontext = MemoryContextSwitchTo(stmt_mcontext);
initStringInfo(&ds);
MemoryContextSwitchTo(oldcontext);
current_param = list_head(stmt->params);
for (cp = stmt->message; *cp; cp++)
{
/*
* Occurrences of a single % are replaced by the next parameter's
* external representation. Double %'s are converted to one %.
*/
if (cp[0] == '%')
{
Oid paramtypeid;
int32 paramtypmod;
Datum paramvalue;
bool paramisnull;
char *extval;
if (cp[1] == '%')
{
appendStringInfoChar(&ds, '%');
cp++;
continue;
}
/* should have been checked at compile time */
if (current_param == NULL)
elog(ERROR, "unexpected RAISE parameter list length");
paramvalue = exec_eval_expr(estate,
(PLpgSQL_expr *) lfirst(current_param),
¶misnull,
¶mtypeid,
¶mtypmod);
if (paramisnull)
extval = "<NULL>";
else
extval = convert_value_to_string(estate,
paramvalue,
paramtypeid);
appendStringInfoString(&ds, extval);
current_param = lnext(current_param);
exec_eval_cleanup(estate);
}
else
appendStringInfoChar(&ds, cp[0]);
}
/* should have been checked at compile time */
if (current_param != NULL)
elog(ERROR, "unexpected RAISE parameter list length");
err_message = ds.data;
}
foreach(lc, stmt->options)
{
PLpgSQL_raise_option *opt = (PLpgSQL_raise_option *) lfirst(lc);
Datum optionvalue;
bool optionisnull;
Oid optiontypeid;
int32 optiontypmod;
char *extval;
optionvalue = exec_eval_expr(estate, opt->expr,
&optionisnull,
&optiontypeid,
&optiontypmod);
if (optionisnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("RAISE statement option cannot be null")));
extval = convert_value_to_string(estate, optionvalue, optiontypeid);
switch (opt->opt_type)
{
case PLPGSQL_RAISEOPTION_ERRCODE:
if (err_code)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("RAISE option already specified: %s",
"ERRCODE")));
err_code = plpgsql_recognize_err_condition(extval, true);
condname = MemoryContextStrdup(stmt_mcontext, extval);
break;
case PLPGSQL_RAISEOPTION_MESSAGE:
SET_RAISE_OPTION_TEXT(err_message, "MESSAGE");
break;
case PLPGSQL_RAISEOPTION_DETAIL:
SET_RAISE_OPTION_TEXT(err_detail, "DETAIL");
break;
case PLPGSQL_RAISEOPTION_HINT:
SET_RAISE_OPTION_TEXT(err_hint, "HINT");
break;
case PLPGSQL_RAISEOPTION_COLUMN:
SET_RAISE_OPTION_TEXT(err_column, "COLUMN");
break;
case PLPGSQL_RAISEOPTION_CONSTRAINT:
SET_RAISE_OPTION_TEXT(err_constraint, "CONSTRAINT");
break;
case PLPGSQL_RAISEOPTION_DATATYPE:
SET_RAISE_OPTION_TEXT(err_datatype, "DATATYPE");
break;
case PLPGSQL_RAISEOPTION_TABLE:
SET_RAISE_OPTION_TEXT(err_table, "TABLE");
break;
case PLPGSQL_RAISEOPTION_SCHEMA:
SET_RAISE_OPTION_TEXT(err_schema, "SCHEMA");
break;
default:
elog(ERROR, "unrecognized raise option: %d", opt->opt_type);
}
exec_eval_cleanup(estate);
}
/* Default code if nothing specified */
if (err_code == 0 && stmt->elog_level >= ERROR)
err_code = ERRCODE_RAISE_EXCEPTION;
/* Default error message if nothing specified */
if (err_message == NULL)
{
if (condname)
{
err_message = condname;
condname = NULL;
}
else
err_message = MemoryContextStrdup(stmt_mcontext,
unpack_sql_state(err_code));
}
/*
* Throw the error (may or may not come back)
*/
ereport(stmt->elog_level,
(err_code ? errcode(err_code) : 0,
errmsg_internal("%s", err_message),
(err_detail != NULL) ? errdetail_internal("%s", err_detail) : 0,
(err_hint != NULL) ? errhint("%s", err_hint) : 0,
(err_column != NULL) ?
err_generic_string(PG_DIAG_COLUMN_NAME, err_column) : 0,
(err_constraint != NULL) ?
err_generic_string(PG_DIAG_CONSTRAINT_NAME, err_constraint) : 0,
(err_datatype != NULL) ?
err_generic_string(PG_DIAG_DATATYPE_NAME, err_datatype) : 0,
(err_table != NULL) ?
err_generic_string(PG_DIAG_TABLE_NAME, err_table) : 0,
(err_schema != NULL) ?
err_generic_string(PG_DIAG_SCHEMA_NAME, err_schema) : 0));
/* Clean up transient strings */
MemoryContextReset(stmt_mcontext);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_assert Assert statement
* ----------
*/
static int
exec_stmt_assert(PLpgSQL_execstate *estate, PLpgSQL_stmt_assert *stmt)
{
bool value;
bool isnull;
/* do nothing when asserts are not enabled */
if (!plpgsql_check_asserts)
return PLPGSQL_RC_OK;
value = exec_eval_boolean(estate, stmt->cond, &isnull);
exec_eval_cleanup(estate);
if (isnull || !value)
{
char *message = NULL;
if (stmt->message != NULL)
{
Datum val;
Oid typeid;
int32 typmod;
val = exec_eval_expr(estate, stmt->message,
&isnull, &typeid, &typmod);
if (!isnull)
message = convert_value_to_string(estate, val, typeid);
/* we mustn't do exec_eval_cleanup here */
}
ereport(ERROR,
(errcode(ERRCODE_ASSERT_FAILURE),
message ? errmsg_internal("%s", message) :
errmsg("assertion failed")));
}
return PLPGSQL_RC_OK;
}
/* ----------
* Initialize a mostly empty execution state
* ----------
*/
static void
plpgsql_estate_setup(PLpgSQL_execstate *estate,
PLpgSQL_function *func,
ReturnSetInfo *rsi,
EState *simple_eval_estate)
{
HASHCTL ctl;
/* this link will be restored at exit from plpgsql_call_handler */
func->cur_estate = estate;
estate->func = func;
estate->trigdata = NULL;
estate->evtrigdata = NULL;
estate->retval = (Datum) 0;
estate->retisnull = true;
estate->rettype = InvalidOid;
estate->fn_rettype = func->fn_rettype;
estate->retistuple = func->fn_retistuple;
estate->retisset = func->fn_retset;
estate->readonly_func = func->fn_readonly;
estate->atomic = true;
estate->exitlabel = NULL;
estate->cur_error = NULL;
estate->tuple_store = NULL;
estate->tuple_store_desc = NULL;
if (rsi)
{
estate->tuple_store_cxt = rsi->econtext->ecxt_per_query_memory;
estate->tuple_store_owner = CurrentResourceOwner;
}
else
{
estate->tuple_store_cxt = NULL;
estate->tuple_store_owner = NULL;
}
estate->rsi = rsi;
estate->found_varno = func->found_varno;
estate->ndatums = func->ndatums;
estate->datums = NULL;
/* the datums array will be filled by copy_plpgsql_datums() */
estate->datum_context = CurrentMemoryContext;
/* initialize our ParamListInfo with appropriate hook functions */
estate->paramLI = makeParamList(0);
estate->paramLI->paramFetch = plpgsql_param_fetch;
estate->paramLI->paramFetchArg = (void *) estate;
estate->paramLI->paramCompile = plpgsql_param_compile;
estate->paramLI->paramCompileArg = NULL; /* not needed */
estate->paramLI->parserSetup = (ParserSetupHook) plpgsql_parser_setup;
estate->paramLI->parserSetupArg = NULL; /* filled during use */
estate->paramLI->numParams = estate->ndatums;
/* set up for use of appropriate simple-expression EState and cast hash */
if (simple_eval_estate)
{
estate->simple_eval_estate = simple_eval_estate;
/* Private cast hash just lives in function's main context */
memset(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(plpgsql_CastHashKey);
ctl.entrysize = sizeof(plpgsql_CastHashEntry);
ctl.hcxt = CurrentMemoryContext;
estate->cast_hash = hash_create("PLpgSQL private cast cache",
16, /* start small and extend */
&ctl,
HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
estate->cast_hash_context = CurrentMemoryContext;
}
else
{
estate->simple_eval_estate = shared_simple_eval_estate;
/* Create the session-wide cast-info hash table if we didn't already */
if (shared_cast_hash == NULL)
{
shared_cast_context = AllocSetContextCreate(TopMemoryContext,
"PLpgSQL cast info",
ALLOCSET_DEFAULT_SIZES);
memset(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(plpgsql_CastHashKey);
ctl.entrysize = sizeof(plpgsql_CastHashEntry);
ctl.hcxt = shared_cast_context;
shared_cast_hash = hash_create("PLpgSQL cast cache",
16, /* start small and extend */
&ctl,
HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
}
estate->cast_hash = shared_cast_hash;
estate->cast_hash_context = shared_cast_context;
}
/*
* We start with no stmt_mcontext; one will be created only if needed.
* That context will be a direct child of the function's main execution
* context. Additional stmt_mcontexts might be created as children of it.
*/
estate->stmt_mcontext = NULL;
estate->stmt_mcontext_parent = CurrentMemoryContext;
estate->eval_tuptable = NULL;
estate->eval_processed = 0;
estate->eval_econtext = NULL;
estate->err_stmt = NULL;
estate->err_text = NULL;
estate->plugin_info = NULL;
/*
* Create an EState and ExprContext for evaluation of simple expressions.
*/
plpgsql_create_econtext(estate);
/*
* Let the plugin see this function before we initialize any local
* PL/pgSQL variables - note that we also give the plugin a few function
* pointers so it can call back into PL/pgSQL for doing things like
* variable assignments and stack traces
*/
if (*plpgsql_plugin_ptr)
{
(*plpgsql_plugin_ptr)->error_callback = plpgsql_exec_error_callback;
(*plpgsql_plugin_ptr)->assign_expr = exec_assign_expr;
if ((*plpgsql_plugin_ptr)->func_setup)
((*plpgsql_plugin_ptr)->func_setup) (estate, func);
}
}
/* ----------
* Release temporary memory used by expression/subselect evaluation
*
* NB: the result of the evaluation is no longer valid after this is done,
* unless it is a pass-by-value datatype.
*
* NB: if you change this code, see also the hacks in exec_assign_value's
* PLPGSQL_DTYPE_ARRAYELEM case for partial cleanup after subscript evals.
* ----------
*/
static void
exec_eval_cleanup(PLpgSQL_execstate *estate)
{
/* Clear result of a full SPI_execute */
if (estate->eval_tuptable != NULL)
SPI_freetuptable(estate->eval_tuptable);
estate->eval_tuptable = NULL;
/*
* Clear result of exec_eval_simple_expr (but keep the econtext). This
* also clears any short-lived allocations done via get_eval_mcontext.
*/
if (estate->eval_econtext != NULL)
ResetExprContext(estate->eval_econtext);
}
/* ----------
* Generate a prepared plan
* ----------
*/
static void
exec_prepare_plan(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr, int cursorOptions,
bool keepplan)
{
SPIPlanPtr plan;
/*
* The grammar can't conveniently set expr->func while building the parse
* tree, so make sure it's set before parser hooks need it.
*/
expr->func = estate->func;
/*
* Generate and save the plan
*/
plan = SPI_prepare_params(expr->query,
(ParserSetupHook) plpgsql_parser_setup,
(void *) expr,
cursorOptions);
if (plan == NULL)
elog(ERROR, "SPI_prepare_params failed for \"%s\": %s",
expr->query, SPI_result_code_string(SPI_result));
if (keepplan)
SPI_keepplan(plan);
expr->plan = plan;
/* Check to see if it's a simple expression */
exec_simple_check_plan(estate, expr);
/*
* Mark expression as not using a read-write param. exec_assign_value has
* to take steps to override this if appropriate; that seems cleaner than
* adding parameters to all other callers.
*/
expr->rwparam = -1;
}
/* ----------
* exec_stmt_execsql Execute an SQL statement (possibly with INTO).
*
* Note: some callers rely on this not touching stmt_mcontext. If it ever
* needs to use that, fix those callers to push/pop stmt_mcontext.
* ----------
*/
static int
exec_stmt_execsql(PLpgSQL_execstate *estate,
PLpgSQL_stmt_execsql *stmt)
{
ParamListInfo paramLI;
int64 tcount;
int rc;
PLpgSQL_expr *expr = stmt->sqlstmt;
int too_many_rows_level = 0;
if (plpgsql_extra_errors & PLPGSQL_XCHECK_TOOMANYROWS)
too_many_rows_level = ERROR;
else if (plpgsql_extra_warnings & PLPGSQL_XCHECK_TOOMANYROWS)
too_many_rows_level = WARNING;
/*
* On the first call for this statement generate the plan, and detect
* whether the statement is INSERT/UPDATE/DELETE
*/
if (expr->plan == NULL)
{
ListCell *l;
exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK, true);
stmt->mod_stmt = false;
foreach(l, SPI_plan_get_plan_sources(expr->plan))
{
CachedPlanSource *plansource = (CachedPlanSource *) lfirst(l);
/*
* We could look at the raw_parse_tree, but it seems simpler to
* check the command tag. Note we should *not* look at the Query
* tree(s), since those are the result of rewriting and could have
* been transmogrified into something else entirely.
*/
if (plansource->commandTag &&
(strcmp(plansource->commandTag, "INSERT") == 0 ||
strcmp(plansource->commandTag, "UPDATE") == 0 ||
strcmp(plansource->commandTag, "DELETE") == 0))
{
stmt->mod_stmt = true;
break;
}
}
}
/*
* Set up ParamListInfo to pass to executor
*/
paramLI = setup_param_list(estate, expr);
/*
* If we have INTO, then we only need one row back ... but if we have INTO
* STRICT or extra check too_many_rows, ask for two rows, so that we can
* verify the statement returns only one. INSERT/UPDATE/DELETE are always
* treated strictly. Without INTO, just run the statement to completion
* (tcount = 0).
*
* We could just ask for two rows always when using INTO, but there are
* some cases where demanding the extra row costs significant time, eg by
* forcing completion of a sequential scan. So don't do it unless we need
* to enforce strictness.
*/
if (stmt->into)
{
if (stmt->strict || stmt->mod_stmt || too_many_rows_level)
tcount = 2;
else
tcount = 1;
}
else
tcount = 0;
/*
* Execute the plan
*/
rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
estate->readonly_func, tcount);
/*
* Check for error, and set FOUND if appropriate (for historical reasons
* we set FOUND only for certain query types).
*
* Note: the command type indicated by return code might not match
* mod_stmt, if there is an INSTEAD OF rule rewriting an UPDATE into an
* INSERT, for example. In that case, the INSERT doesn't have canSetTag
* set, mod_stmt is false, and SPI_execute_plan sets SPI_processed to
* zero. We'll set FOUND to false here in that case. If the statement is
* rewritten into a utility statement, however, FOUND is left unchanged.
* Arguably that's a bug, but changing it now could break applications.
*/
switch (rc)
{
case SPI_OK_SELECT:
exec_set_found(estate, (SPI_processed != 0));
break;
case SPI_OK_INSERT:
case SPI_OK_UPDATE:
case SPI_OK_DELETE:
case SPI_OK_INSERT_RETURNING:
case SPI_OK_UPDATE_RETURNING:
case SPI_OK_DELETE_RETURNING:
exec_set_found(estate, (SPI_processed != 0));
break;
case SPI_OK_SELINTO:
case SPI_OK_UTILITY:
break;
case SPI_OK_REWRITTEN:
/*
* The command was rewritten into another kind of command. It's
* not clear what FOUND would mean in that case (and SPI doesn't
* return the row count either), so just set it to false. Note
* that we can't assert anything about mod_stmt here.
*/
exec_set_found(estate, false);
break;
/* Some SPI errors deserve specific error messages */
case SPI_ERROR_COPY:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot COPY to/from client in PL/pgSQL")));
break;
case SPI_ERROR_TRANSACTION:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unsupported transaction command in PL/pgSQL")));
break;
default:
elog(ERROR, "SPI_execute_plan_with_paramlist failed executing query \"%s\": %s",
expr->query, SPI_result_code_string(rc));
break;
}
/* All variants should save result info for GET DIAGNOSTICS */
estate->eval_processed = SPI_processed;
/* Process INTO if present */
if (stmt->into)
{
SPITupleTable *tuptab = SPI_tuptable;
uint64 n = SPI_processed;
PLpgSQL_variable *target;
/* If the statement did not return a tuple table, complain */
if (tuptab == NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("INTO used with a command that cannot return data")));
/* Fetch target's datum entry */
target = (PLpgSQL_variable *) estate->datums[stmt->target->dno];
/*
* If SELECT ... INTO specified STRICT, and the query didn't find
* exactly one row, throw an error. If STRICT was not specified, then
* allow the query to find any number of rows.
*/
if (n == 0)
{
if (stmt->strict)
{
char *errdetail;
if (estate->func->print_strict_params)
errdetail = format_expr_params(estate, expr);
else
errdetail = NULL;
ereport(ERROR,
(errcode(ERRCODE_NO_DATA_FOUND),
errmsg("query returned no rows"),
errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
}
/* set the target to NULL(s) */
exec_move_row(estate, target, NULL, tuptab->tupdesc);
}
else
{
if (n > 1 && (stmt->strict || stmt->mod_stmt || too_many_rows_level))
{
char *errdetail;
int errlevel;
if (estate->func->print_strict_params)
errdetail = format_expr_params(estate, expr);
else
errdetail = NULL;
errlevel = (stmt->strict || stmt->mod_stmt) ? ERROR : too_many_rows_level;
ereport(errlevel,
(errcode(ERRCODE_TOO_MANY_ROWS),
errmsg("query returned more than one row"),
errdetail ? errdetail_internal("parameters: %s", errdetail) : 0,
errhint("Make sure the query returns a single row, or use LIMIT 1.")));
}
/* Put the first result row into the target */
exec_move_row(estate, target, tuptab->vals[0], tuptab->tupdesc);
}
/* Clean up */
exec_eval_cleanup(estate);
SPI_freetuptable(SPI_tuptable);
}
else
{
/* If the statement returned a tuple table, complain */
if (SPI_tuptable != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("query has no destination for result data"),
(rc == SPI_OK_SELECT) ? errhint("If you want to discard the results of a SELECT, use PERFORM instead.") : 0));
}
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_dynexecute Execute a dynamic SQL query
* (possibly with INTO).
* ----------
*/
static int
exec_stmt_dynexecute(PLpgSQL_execstate *estate,
PLpgSQL_stmt_dynexecute *stmt)
{
Datum query;
bool isnull;
Oid restype;
int32 restypmod;
char *querystr;
int exec_res;
PreparedParamsData *ppd = NULL;
MemoryContext stmt_mcontext = get_stmt_mcontext(estate);
/*
* First we evaluate the string expression after the EXECUTE keyword. Its
* result is the querystring we have to execute.
*/
query = exec_eval_expr(estate, stmt->query, &isnull, &restype, &restypmod);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("query string argument of EXECUTE is null")));
/* Get the C-String representation */
querystr = convert_value_to_string(estate, query, restype);
/* copy it into the stmt_mcontext before we clean up */
querystr = MemoryContextStrdup(stmt_mcontext, querystr);
exec_eval_cleanup(estate);
/*
* Execute the query without preparing a saved plan.
*/
if (stmt->params)
{
ppd = exec_eval_using_params(estate, stmt->params);
exec_res = SPI_execute_with_args(querystr,
ppd->nargs, ppd->types,
ppd->values, ppd->nulls,
estate->readonly_func, 0);
}
else
exec_res = SPI_execute(querystr, estate->readonly_func, 0);
switch (exec_res)
{
case SPI_OK_SELECT:
case SPI_OK_INSERT:
case SPI_OK_UPDATE:
case SPI_OK_DELETE:
case SPI_OK_INSERT_RETURNING:
case SPI_OK_UPDATE_RETURNING:
case SPI_OK_DELETE_RETURNING:
case SPI_OK_UTILITY:
case SPI_OK_REWRITTEN:
break;
case 0:
/*
* Also allow a zero return, which implies the querystring
* contained no commands.
*/
break;
case SPI_OK_SELINTO:
/*
* We want to disallow SELECT INTO for now, because its behavior
* is not consistent with SELECT INTO in a normal plpgsql context.
* (We need to reimplement EXECUTE to parse the string as a
* plpgsql command, not just feed it to SPI_execute.) This is not
* a functional limitation because CREATE TABLE AS is allowed.
*/
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("EXECUTE of SELECT ... INTO is not implemented"),
errhint("You might want to use EXECUTE ... INTO or EXECUTE CREATE TABLE ... AS instead.")));
break;
/* Some SPI errors deserve specific error messages */
case SPI_ERROR_COPY:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot COPY to/from client in PL/pgSQL")));
break;
case SPI_ERROR_TRANSACTION:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("EXECUTE of transaction commands is not implemented")));
break;
default:
elog(ERROR, "SPI_execute failed executing query \"%s\": %s",
querystr, SPI_result_code_string(exec_res));
break;
}
/* Save result info for GET DIAGNOSTICS */
estate->eval_processed = SPI_processed;
/* Process INTO if present */
if (stmt->into)
{
SPITupleTable *tuptab = SPI_tuptable;
uint64 n = SPI_processed;
PLpgSQL_variable *target;
/* If the statement did not return a tuple table, complain */
if (tuptab == NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("INTO used with a command that cannot return data")));
/* Fetch target's datum entry */
target = (PLpgSQL_variable *) estate->datums[stmt->target->dno];
/*
* If SELECT ... INTO specified STRICT, and the query didn't find
* exactly one row, throw an error. If STRICT was not specified, then
* allow the query to find any number of rows.
*/
if (n == 0)
{
if (stmt->strict)
{
char *errdetail;
if (estate->func->print_strict_params)
errdetail = format_preparedparamsdata(estate, ppd);
else
errdetail = NULL;
ereport(ERROR,
(errcode(ERRCODE_NO_DATA_FOUND),
errmsg("query returned no rows"),
errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
}
/* set the target to NULL(s) */
exec_move_row(estate, target, NULL, tuptab->tupdesc);
}
else
{
if (n > 1 && stmt->strict)
{
char *errdetail;
if (estate->func->print_strict_params)
errdetail = format_preparedparamsdata(estate, ppd);
else
errdetail = NULL;
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ROWS),
errmsg("query returned more than one row"),
errdetail ? errdetail_internal("parameters: %s", errdetail) : 0));
}
/* Put the first result row into the target */
exec_move_row(estate, target, tuptab->vals[0], tuptab->tupdesc);
}
/* clean up after exec_move_row() */
exec_eval_cleanup(estate);
}
else
{
/*
* It might be a good idea to raise an error if the query returned
* tuples that are being ignored, but historically we have not done
* that.
*/
}
/* Release any result from SPI_execute, as well as transient data */
SPI_freetuptable(SPI_tuptable);
MemoryContextReset(stmt_mcontext);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_dynfors Execute a dynamic query, assign each
* tuple to a record or row and
* execute a group of statements
* for it.
* ----------
*/
static int
exec_stmt_dynfors(PLpgSQL_execstate *estate, PLpgSQL_stmt_dynfors *stmt)
{
Portal portal;
int rc;
portal = exec_dynquery_with_params(estate, stmt->query, stmt->params,
NULL, 0);
/*
* Execute the loop
*/
rc = exec_for_query(estate, (PLpgSQL_stmt_forq *) stmt, portal, true);
/*
* Close the implicit cursor
*/
SPI_cursor_close(portal);
return rc;
}
/* ----------
* exec_stmt_open Execute an OPEN cursor statement
* ----------
*/
static int
exec_stmt_open(PLpgSQL_execstate *estate, PLpgSQL_stmt_open *stmt)
{
PLpgSQL_var *curvar;
MemoryContext stmt_mcontext = NULL;
char *curname = NULL;
PLpgSQL_expr *query;
Portal portal;
ParamListInfo paramLI;
/* ----------
* Get the cursor variable and if it has an assigned name, check
* that it's not in use currently.
* ----------
*/
curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
if (!curvar->isnull)
{
MemoryContext oldcontext;
/* We only need stmt_mcontext to hold the cursor name string */
stmt_mcontext = get_stmt_mcontext(estate);
oldcontext = MemoryContextSwitchTo(stmt_mcontext);
curname = TextDatumGetCString(curvar->value);
MemoryContextSwitchTo(oldcontext);
if (SPI_cursor_find(curname) != NULL)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_CURSOR),
errmsg("cursor \"%s\" already in use", curname)));
}
/* ----------
* Process the OPEN according to it's type.
* ----------
*/
if (stmt->query != NULL)
{
/* ----------
* This is an OPEN refcursor FOR SELECT ...
*
* We just make sure the query is planned. The real work is
* done downstairs.
* ----------
*/
query = stmt->query;
if (query->plan == NULL)
exec_prepare_plan(estate, query, stmt->cursor_options | CURSOR_OPT_UPDATABLE, true);
}
else if (stmt->dynquery != NULL)
{
/* ----------
* This is an OPEN refcursor FOR EXECUTE ...
* ----------
*/
portal = exec_dynquery_with_params(estate,
stmt->dynquery,
stmt->params,
curname,
stmt->cursor_options | CURSOR_OPT_UPDATABLE);
/*
* If cursor variable was NULL, store the generated portal name in it.
* Note: exec_dynquery_with_params already reset the stmt_mcontext, so
* curname is a dangling pointer here; but testing it for nullness is
* OK.
*/
if (curname == NULL)
assign_text_var(estate, curvar, portal->name);
return PLPGSQL_RC_OK;
}
else
{
/* ----------
* This is an OPEN cursor
*
* Note: parser should already have checked that statement supplies
* args iff cursor needs them, but we check again to be safe.
* ----------
*/
if (stmt->argquery != NULL)
{
/* ----------
* OPEN CURSOR with args. We fake a SELECT ... INTO ...
* statement to evaluate the args and put 'em into the
* internal row.
* ----------
*/
PLpgSQL_stmt_execsql set_args;
if (curvar->cursor_explicit_argrow < 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("arguments given for cursor without arguments")));
memset(&set_args, 0, sizeof(set_args));
set_args.cmd_type = PLPGSQL_STMT_EXECSQL;
set_args.lineno = stmt->lineno;
set_args.sqlstmt = stmt->argquery;
set_args.into = true;
/* XXX historically this has not been STRICT */
set_args.target = (PLpgSQL_variable *)
(estate->datums[curvar->cursor_explicit_argrow]);
if (exec_stmt_execsql(estate, &set_args) != PLPGSQL_RC_OK)
elog(ERROR, "open cursor failed during argument processing");
}
else
{
if (curvar->cursor_explicit_argrow >= 0)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("arguments required for cursor")));
}
query = curvar->cursor_explicit_expr;
if (query->plan == NULL)
exec_prepare_plan(estate, query, curvar->cursor_options | CURSOR_OPT_UPDATABLE, true);
}
/*
* Set up ParamListInfo for this query
*/
paramLI = setup_param_list(estate, query);
/*
* Open the cursor (the paramlist will get copied into the portal)
*/
portal = SPI_cursor_open_with_paramlist(curname, query->plan,
paramLI,
estate->readonly_func);
if (portal == NULL)
elog(ERROR, "could not open cursor: %s",
SPI_result_code_string(SPI_result));
/*
* If cursor variable was NULL, store the generated portal name in it
*/
if (curname == NULL)
assign_text_var(estate, curvar, portal->name);
/* If we had any transient data, clean it up */
exec_eval_cleanup(estate);
if (stmt_mcontext)
MemoryContextReset(stmt_mcontext);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_fetch Fetch from a cursor into a target, or just
* move the current position of the cursor
* ----------
*/
static int
exec_stmt_fetch(PLpgSQL_execstate *estate, PLpgSQL_stmt_fetch *stmt)
{
PLpgSQL_var *curvar;
long how_many = stmt->how_many;
SPITupleTable *tuptab;
Portal portal;
char *curname;
uint64 n;
MemoryContext oldcontext;
/* ----------
* Get the portal of the cursor by name
* ----------
*/
curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
if (curvar->isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("cursor variable \"%s\" is null", curvar->refname)));
/* Use eval_mcontext for short-lived string */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
curname = TextDatumGetCString(curvar->value);
MemoryContextSwitchTo(oldcontext);
portal = SPI_cursor_find(curname);
if (portal == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_CURSOR),
errmsg("cursor \"%s\" does not exist", curname)));
/* Calculate position for FETCH_RELATIVE or FETCH_ABSOLUTE */
if (stmt->expr)
{
bool isnull;
/* XXX should be doing this in LONG not INT width */
how_many = exec_eval_integer(estate, stmt->expr, &isnull);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("relative or absolute cursor position is null")));
exec_eval_cleanup(estate);
}
if (!stmt->is_move)
{
PLpgSQL_variable *target;
/* ----------
* Fetch 1 tuple from the cursor
* ----------
*/
SPI_scroll_cursor_fetch(portal, stmt->direction, how_many);
tuptab = SPI_tuptable;
n = SPI_processed;
/* ----------
* Set the target appropriately.
* ----------
*/
target = (PLpgSQL_variable *) estate->datums[stmt->target->dno];
if (n == 0)
exec_move_row(estate, target, NULL, tuptab->tupdesc);
else
exec_move_row(estate, target, tuptab->vals[0], tuptab->tupdesc);
exec_eval_cleanup(estate);
SPI_freetuptable(tuptab);
}
else
{
/* Move the cursor */
SPI_scroll_cursor_move(portal, stmt->direction, how_many);
n = SPI_processed;
}
/* Set the ROW_COUNT and the global FOUND variable appropriately. */
estate->eval_processed = n;
exec_set_found(estate, n != 0);
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_close Close a cursor
* ----------
*/
static int
exec_stmt_close(PLpgSQL_execstate *estate, PLpgSQL_stmt_close *stmt)
{
PLpgSQL_var *curvar;
Portal portal;
char *curname;
MemoryContext oldcontext;
/* ----------
* Get the portal of the cursor by name
* ----------
*/
curvar = (PLpgSQL_var *) (estate->datums[stmt->curvar]);
if (curvar->isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("cursor variable \"%s\" is null", curvar->refname)));
/* Use eval_mcontext for short-lived string */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
curname = TextDatumGetCString(curvar->value);
MemoryContextSwitchTo(oldcontext);
portal = SPI_cursor_find(curname);
if (portal == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_CURSOR),
errmsg("cursor \"%s\" does not exist", curname)));
/* ----------
* And close it.
* ----------
*/
SPI_cursor_close(portal);
return PLPGSQL_RC_OK;
}
/*
* exec_stmt_commit
*
* Commit the transaction.
*/
static int
exec_stmt_commit(PLpgSQL_execstate *estate, PLpgSQL_stmt_commit *stmt)
{
if (stmt->chain)
SPI_commit_and_chain();
else
{
SPI_commit();
SPI_start_transaction();
}
estate->simple_eval_estate = NULL;
plpgsql_create_econtext(estate);
return PLPGSQL_RC_OK;
}
/*
* exec_stmt_rollback
*
* Abort the transaction.
*/
static int
exec_stmt_rollback(PLpgSQL_execstate *estate, PLpgSQL_stmt_rollback *stmt)
{
if (stmt->chain)
SPI_rollback_and_chain();
else
{
SPI_rollback();
SPI_start_transaction();
}
estate->simple_eval_estate = NULL;
plpgsql_create_econtext(estate);
return PLPGSQL_RC_OK;
}
/*
* exec_stmt_set
*
* Execute SET/RESET statement.
*
* We just parse and execute the statement normally, but we have to do it
* without setting a snapshot, for things like SET TRANSACTION.
*/
static int
exec_stmt_set(PLpgSQL_execstate *estate, PLpgSQL_stmt_set *stmt)
{
PLpgSQL_expr *expr = stmt->expr;
int rc;
if (expr->plan == NULL)
{
exec_prepare_plan(estate, expr, 0, true);
expr->plan->no_snapshots = true;
}
rc = SPI_execute_plan(expr->plan, NULL, NULL, estate->readonly_func, 0);
if (rc != SPI_OK_UTILITY)
elog(ERROR, "SPI_execute_plan failed executing query \"%s\": %s",
expr->query, SPI_result_code_string(rc));
return PLPGSQL_RC_OK;
}
/* ----------
* exec_assign_expr Put an expression's result into a variable.
* ----------
*/
static void
exec_assign_expr(PLpgSQL_execstate *estate, PLpgSQL_datum *target,
PLpgSQL_expr *expr)
{
Datum value;
bool isnull;
Oid valtype;
int32 valtypmod;
/*
* If first time through, create a plan for this expression, and then see
* if we can pass the target variable as a read-write parameter to the
* expression. (This is a bit messy, but it seems cleaner than modifying
* the API of exec_eval_expr for the purpose.)
*/
if (expr->plan == NULL)
{
exec_prepare_plan(estate, expr, 0, true);
if (target->dtype == PLPGSQL_DTYPE_VAR)
exec_check_rw_parameter(expr, target->dno);
}
value = exec_eval_expr(estate, expr, &isnull, &valtype, &valtypmod);
exec_assign_value(estate, target, value, isnull, valtype, valtypmod);
exec_eval_cleanup(estate);
}
/* ----------
* exec_assign_c_string Put a C string into a text variable.
*
* We take a NULL pointer as signifying empty string, not SQL null.
*
* As with the underlying exec_assign_value, caller is expected to do
* exec_eval_cleanup later.
* ----------
*/
static void
exec_assign_c_string(PLpgSQL_execstate *estate, PLpgSQL_datum *target,
const char *str)
{
text *value;
MemoryContext oldcontext;
/* Use eval_mcontext for short-lived text value */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
if (str != NULL)
value = cstring_to_text(str);
else
value = cstring_to_text("");
MemoryContextSwitchTo(oldcontext);
exec_assign_value(estate, target, PointerGetDatum(value), false,
TEXTOID, -1);
}
/* ----------
* exec_assign_value Put a value into a target datum
*
* Note: in some code paths, this will leak memory in the eval_mcontext;
* we assume that will be cleaned up later by exec_eval_cleanup. We cannot
* call exec_eval_cleanup here for fear of destroying the input Datum value.
* ----------
*/
static void
exec_assign_value(PLpgSQL_execstate *estate,
PLpgSQL_datum *target,
Datum value, bool isNull,
Oid valtype, int32 valtypmod)
{
switch (target->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
/*
* Target is a variable
*/
PLpgSQL_var *var = (PLpgSQL_var *) target;
Datum newvalue;
newvalue = exec_cast_value(estate,
value,
&isNull,
valtype,
valtypmod,
var->datatype->typoid,
var->datatype->atttypmod);
if (isNull && var->notnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("null value cannot be assigned to variable \"%s\" declared NOT NULL",
var->refname)));
/*
* If type is by-reference, copy the new value (which is
* probably in the eval_mcontext) into the procedure's main
* memory context. But if it's a read/write reference to an
* expanded object, no physical copy needs to happen; at most
* we need to reparent the object's memory context.
*
* If it's an array, we force the value to be stored in R/W
* expanded form. This wins if the function later does, say,
* a lot of array subscripting operations on the variable, and
* otherwise might lose. We might need to use a different
* heuristic, but it's too soon to tell. Also, are there
* cases where it'd be useful to force non-array values into
* expanded form?
*/
if (!var->datatype->typbyval && !isNull)
{
if (var->datatype->typisarray &&
!VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(newvalue)))
{
/* array and not already R/W, so apply expand_array */
newvalue = expand_array(newvalue,
estate->datum_context,
NULL);
}
else
{
/* else transfer value if R/W, else just datumCopy */
newvalue = datumTransfer(newvalue,
false,
var->datatype->typlen);
}
}
/*
* Now free the old value, if any, and assign the new one. But
* skip the assignment if old and new values are the same.
* Note that for expanded objects, this test is necessary and
* cannot reliably be made any earlier; we have to be looking
* at the object's standard R/W pointer to be sure pointer
* equality is meaningful.
*
* Also, if it's a promise variable, we should disarm the
* promise in any case --- otherwise, assigning null to an
* armed promise variable would fail to disarm the promise.
*/
if (var->value != newvalue || var->isnull || isNull)
assign_simple_var(estate, var, newvalue, isNull,
(!var->datatype->typbyval && !isNull));
else
var->promise = PLPGSQL_PROMISE_NONE;
break;
}
case PLPGSQL_DTYPE_ROW:
{
/*
* Target is a row variable
*/
PLpgSQL_row *row = (PLpgSQL_row *) target;
if (isNull)
{
/* If source is null, just assign nulls to the row */
exec_move_row(estate, (PLpgSQL_variable *) row,
NULL, NULL);
}
else
{
/* Source must be of RECORD or composite type */
if (!type_is_rowtype(valtype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot assign non-composite value to a row variable")));
exec_move_row_from_datum(estate, (PLpgSQL_variable *) row,
value);
}
break;
}
case PLPGSQL_DTYPE_REC:
{
/*
* Target is a record variable
*/
PLpgSQL_rec *rec = (PLpgSQL_rec *) target;
if (isNull)
{
if (rec->notnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("null value cannot be assigned to variable \"%s\" declared NOT NULL",
rec->refname)));
/* Set variable to a simple NULL */
exec_move_row(estate, (PLpgSQL_variable *) rec,
NULL, NULL);
}
else
{
/* Source must be of RECORD or composite type */
if (!type_is_rowtype(valtype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("cannot assign non-composite value to a record variable")));
exec_move_row_from_datum(estate, (PLpgSQL_variable *) rec,
value);
}
break;
}
case PLPGSQL_DTYPE_RECFIELD:
{
/*
* Target is a field of a record
*/
PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) target;
PLpgSQL_rec *rec;
ExpandedRecordHeader *erh;
rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
erh = rec->erh;
/*
* If record variable is NULL, instantiate it if it has a
* named composite type, else complain. (This won't change
* the logical state of the record, but if we successfully
* assign below, the unassigned fields will all become NULLs.)
*/
if (erh == NULL)
{
instantiate_empty_record_variable(estate, rec);
erh = rec->erh;
}
/*
* Look up the field's properties if we have not already, or
* if the tuple descriptor ID changed since last time.
*/
if (unlikely(recfield->rectupledescid != erh->er_tupdesc_id))
{
if (!expanded_record_lookup_field(erh,
recfield->fieldname,
&recfield->finfo))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("record \"%s\" has no field \"%s\"",
rec->refname, recfield->fieldname)));
recfield->rectupledescid = erh->er_tupdesc_id;
}
/* We don't support assignments to system columns. */
if (recfield->finfo.fnumber <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot assign to system column \"%s\"",
recfield->fieldname)));
/* Cast the new value to the right type, if needed. */
value = exec_cast_value(estate,
value,
&isNull,
valtype,
valtypmod,
recfield->finfo.ftypeid,
recfield->finfo.ftypmod);
/* And assign it. */
expanded_record_set_field(erh, recfield->finfo.fnumber,
value, isNull, !estate->atomic);
break;
}
case PLPGSQL_DTYPE_ARRAYELEM:
{
/*
* Target is an element of an array
*/
PLpgSQL_arrayelem *arrayelem;
int nsubscripts;
int i;
PLpgSQL_expr *subscripts[MAXDIM];
int subscriptvals[MAXDIM];
Datum oldarraydatum,
newarraydatum,
coerced_value;
bool oldarrayisnull;
Oid parenttypoid;
int32 parenttypmod;
SPITupleTable *save_eval_tuptable;
MemoryContext oldcontext;
/*
* We need to do subscript evaluation, which might require
* evaluating general expressions; and the caller might have
* done that too in order to prepare the input Datum. We have
* to save and restore the caller's SPI_execute result, if
* any.
*/
save_eval_tuptable = estate->eval_tuptable;
estate->eval_tuptable = NULL;
/*
* To handle constructs like x[1][2] := something, we have to
* be prepared to deal with a chain of arrayelem datums. Chase
* back to find the base array datum, and save the subscript
* expressions as we go. (We are scanning right to left here,
* but want to evaluate the subscripts left-to-right to
* minimize surprises.) Note that arrayelem is left pointing
* to the leftmost arrayelem datum, where we will cache the
* array element type data.
*/
nsubscripts = 0;
do
{
arrayelem = (PLpgSQL_arrayelem *) target;
if (nsubscripts >= MAXDIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
nsubscripts + 1, MAXDIM)));
subscripts[nsubscripts++] = arrayelem->subscript;
target = estate->datums[arrayelem->arrayparentno];
} while (target->dtype == PLPGSQL_DTYPE_ARRAYELEM);
/* Fetch current value of array datum */
exec_eval_datum(estate, target,
&parenttypoid, &parenttypmod,
&oldarraydatum, &oldarrayisnull);
/* Update cached type data if necessary */
if (arrayelem->parenttypoid != parenttypoid ||
arrayelem->parenttypmod != parenttypmod)
{
Oid arraytypoid;
int32 arraytypmod = parenttypmod;
int16 arraytyplen;
Oid elemtypoid;
int16 elemtyplen;
bool elemtypbyval;
char elemtypalign;
/* If target is domain over array, reduce to base type */
arraytypoid = getBaseTypeAndTypmod(parenttypoid,
&arraytypmod);
/* ... and identify the element type */
elemtypoid = get_element_type(arraytypoid);
if (!OidIsValid(elemtypoid))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("subscripted object is not an array")));
/* Collect needed data about the types */
arraytyplen = get_typlen(arraytypoid);
get_typlenbyvalalign(elemtypoid,
&elemtyplen,
&elemtypbyval,
&elemtypalign);
/* Now safe to update the cached data */
arrayelem->parenttypoid = parenttypoid;
arrayelem->parenttypmod = parenttypmod;
arrayelem->arraytypoid = arraytypoid;
arrayelem->arraytypmod = arraytypmod;
arrayelem->arraytyplen = arraytyplen;
arrayelem->elemtypoid = elemtypoid;
arrayelem->elemtyplen = elemtyplen;
arrayelem->elemtypbyval = elemtypbyval;
arrayelem->elemtypalign = elemtypalign;
}
/*
* Evaluate the subscripts, switch into left-to-right order.
* Like the expression built by ExecInitSubscriptingRef(),
* complain if any subscript is null.
*/
for (i = 0; i < nsubscripts; i++)
{
bool subisnull;
subscriptvals[i] =
exec_eval_integer(estate,
subscripts[nsubscripts - 1 - i],
&subisnull);
if (estate->eval_tuptable != NULL)
{
SPI_freetuptable(estate->eval_tuptable);
estate->eval_tuptable = NULL;
}
if (subisnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("array subscript in assignment must not be null")));
/*
* Clean up in case the subscript expression wasn't
* simple. We can't do exec_eval_cleanup, but we can do
* this much (which is safe because the integer subscript
* value is surely pass-by-value), and we must do it in
* case the next subscript expression isn't simple either.
*/
if (estate->eval_tuptable != NULL)
SPI_freetuptable(estate->eval_tuptable);
estate->eval_tuptable = NULL;
}
/* Now we can restore caller's SPI_execute result if any. */
Assert(estate->eval_tuptable == NULL);
estate->eval_tuptable = save_eval_tuptable;
/* Coerce source value to match array element type. */
coerced_value = exec_cast_value(estate,
value,
&isNull,
valtype,
valtypmod,
arrayelem->elemtypoid,
arrayelem->arraytypmod);
/*
* If the original array is null, cons up an empty array so
* that the assignment can proceed; we'll end with a
* one-element array containing just the assigned-to
* subscript. This only works for varlena arrays, though; for
* fixed-length array types we skip the assignment. We can't
* support assignment of a null entry into a fixed-length
* array, either, so that's a no-op too. This is all ugly but
* corresponds to the current behavior of execExpr*.c.
*/
if (arrayelem->arraytyplen > 0 && /* fixed-length array? */
(oldarrayisnull || isNull))
return;
/* empty array, if any, and newarraydatum are short-lived */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
if (oldarrayisnull)
oldarraydatum = PointerGetDatum(construct_empty_array(arrayelem->elemtypoid));
/*
* Build the modified array value.
*/
newarraydatum = array_set_element(oldarraydatum,
nsubscripts,
subscriptvals,
coerced_value,
isNull,
arrayelem->arraytyplen,
arrayelem->elemtyplen,
arrayelem->elemtypbyval,
arrayelem->elemtypalign);
MemoryContextSwitchTo(oldcontext);
/*
* Assign the new array to the base variable. It's never NULL
* at this point. Note that if the target is a domain,
* coercing the base array type back up to the domain will
* happen within exec_assign_value.
*/
exec_assign_value(estate, target,
newarraydatum,
false,
arrayelem->arraytypoid,
arrayelem->arraytypmod);
break;
}
default:
elog(ERROR, "unrecognized dtype: %d", target->dtype);
}
}
/*
* exec_eval_datum Get current value of a PLpgSQL_datum
*
* The type oid, typmod, value in Datum format, and null flag are returned.
*
* At present this doesn't handle PLpgSQL_expr or PLpgSQL_arrayelem datums;
* that's not needed because we never pass references to such datums to SPI.
*
* NOTE: the returned Datum points right at the stored value in the case of
* pass-by-reference datatypes. Generally callers should take care not to
* modify the stored value. Some callers intentionally manipulate variables
* referenced by R/W expanded pointers, though; it is those callers'
* responsibility that the results are semantically OK.
*
* In some cases we have to palloc a return value, and in such cases we put
* it into the estate's eval_mcontext.
*/
static void
exec_eval_datum(PLpgSQL_execstate *estate,
PLpgSQL_datum *datum,
Oid *typeid,
int32 *typetypmod,
Datum *value,
bool *isnull)
{
MemoryContext oldcontext;
switch (datum->dtype)
{
case PLPGSQL_DTYPE_PROMISE:
/* fulfill promise if needed, then handle like regular var */
plpgsql_fulfill_promise(estate, (PLpgSQL_var *) datum);
/* FALL THRU */
case PLPGSQL_DTYPE_VAR:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
*typeid = var->datatype->typoid;
*typetypmod = var->datatype->atttypmod;
*value = var->value;
*isnull = var->isnull;
break;
}
case PLPGSQL_DTYPE_ROW:
{
PLpgSQL_row *row = (PLpgSQL_row *) datum;
HeapTuple tup;
/* We get here if there are multiple OUT parameters */
if (!row->rowtupdesc) /* should not happen */
elog(ERROR, "row variable has no tupdesc");
/* Make sure we have a valid type/typmod setting */
BlessTupleDesc(row->rowtupdesc);
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
tup = make_tuple_from_row(estate, row, row->rowtupdesc);
if (tup == NULL) /* should not happen */
elog(ERROR, "row not compatible with its own tupdesc");
*typeid = row->rowtupdesc->tdtypeid;
*typetypmod = row->rowtupdesc->tdtypmod;
*value = HeapTupleGetDatum(tup);
*isnull = false;
MemoryContextSwitchTo(oldcontext);
break;
}
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;
if (rec->erh == NULL)
{
/* Treat uninstantiated record as a simple NULL */
*value = (Datum) 0;
*isnull = true;
/* Report variable's declared type */
*typeid = rec->rectypeid;
*typetypmod = -1;
}
else
{
if (ExpandedRecordIsEmpty(rec->erh))
{
/* Empty record is also a NULL */
*value = (Datum) 0;
*isnull = true;
}
else
{
*value = ExpandedRecordGetDatum(rec->erh);
*isnull = false;
}
if (rec->rectypeid != RECORDOID)
{
/* Report variable's declared type, if not RECORD */
*typeid = rec->rectypeid;
*typetypmod = -1;
}
else
{
/* Report record's actual type if declared RECORD */
*typeid = rec->erh->er_typeid;
*typetypmod = rec->erh->er_typmod;
}
}
break;
}
case PLPGSQL_DTYPE_RECFIELD:
{
PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
PLpgSQL_rec *rec;
ExpandedRecordHeader *erh;
rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
erh = rec->erh;
/*
* If record variable is NULL, instantiate it if it has a
* named composite type, else complain. (This won't change
* the logical state of the record: it's still NULL.)
*/
if (erh == NULL)
{
instantiate_empty_record_variable(estate, rec);
erh = rec->erh;
}
/*
* Look up the field's properties if we have not already, or
* if the tuple descriptor ID changed since last time.
*/
if (unlikely(recfield->rectupledescid != erh->er_tupdesc_id))
{
if (!expanded_record_lookup_field(erh,
recfield->fieldname,
&recfield->finfo))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("record \"%s\" has no field \"%s\"",
rec->refname, recfield->fieldname)));
recfield->rectupledescid = erh->er_tupdesc_id;
}
/* Report type data. */
*typeid = recfield->finfo.ftypeid;
*typetypmod = recfield->finfo.ftypmod;
/* And fetch the field value. */
*value = expanded_record_get_field(erh,
recfield->finfo.fnumber,
isnull);
break;
}
default:
elog(ERROR, "unrecognized dtype: %d", datum->dtype);
}
}
/*
* plpgsql_exec_get_datum_type Get datatype of a PLpgSQL_datum
*
* This is the same logic as in exec_eval_datum, but we skip acquiring
* the actual value of the variable. Also, needn't support DTYPE_ROW.
*/
Oid
plpgsql_exec_get_datum_type(PLpgSQL_execstate *estate,
PLpgSQL_datum *datum)
{
Oid typeid;
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
typeid = var->datatype->typoid;
break;
}
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;
if (rec->erh == NULL || rec->rectypeid != RECORDOID)
{
/* Report variable's declared type */
typeid = rec->rectypeid;
}
else
{
/* Report record's actual type if declared RECORD */
typeid = rec->erh->er_typeid;
}
break;
}
case PLPGSQL_DTYPE_RECFIELD:
{
PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
PLpgSQL_rec *rec;
rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
/*
* If record variable is NULL, instantiate it if it has a
* named composite type, else complain. (This won't change
* the logical state of the record: it's still NULL.)
*/
if (rec->erh == NULL)
instantiate_empty_record_variable(estate, rec);
/*
* Look up the field's properties if we have not already, or
* if the tuple descriptor ID changed since last time.
*/
if (unlikely(recfield->rectupledescid != rec->erh->er_tupdesc_id))
{
if (!expanded_record_lookup_field(rec->erh,
recfield->fieldname,
&recfield->finfo))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("record \"%s\" has no field \"%s\"",
rec->refname, recfield->fieldname)));
recfield->rectupledescid = rec->erh->er_tupdesc_id;
}
typeid = recfield->finfo.ftypeid;
break;
}
default:
elog(ERROR, "unrecognized dtype: %d", datum->dtype);
typeid = InvalidOid; /* keep compiler quiet */
break;
}
return typeid;
}
/*
* plpgsql_exec_get_datum_type_info Get datatype etc of a PLpgSQL_datum
*
* An extended version of plpgsql_exec_get_datum_type, which also retrieves the
* typmod and collation of the datum. Note however that we don't report the
* possibly-mutable typmod of RECORD values, but say -1 always.
*/
void
plpgsql_exec_get_datum_type_info(PLpgSQL_execstate *estate,
PLpgSQL_datum *datum,
Oid *typeId, int32 *typMod, Oid *collation)
{
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
{
PLpgSQL_var *var = (PLpgSQL_var *) datum;
*typeId = var->datatype->typoid;
*typMod = var->datatype->atttypmod;
*collation = var->datatype->collation;
break;
}
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) datum;
if (rec->erh == NULL || rec->rectypeid != RECORDOID)
{
/* Report variable's declared type */
*typeId = rec->rectypeid;
*typMod = -1;
}
else
{
/* Report record's actual type if declared RECORD */
*typeId = rec->erh->er_typeid;
/* do NOT return the mutable typmod of a RECORD variable */
*typMod = -1;
}
/* composite types are never collatable */
*collation = InvalidOid;
break;
}
case PLPGSQL_DTYPE_RECFIELD:
{
PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
PLpgSQL_rec *rec;
rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
/*
* If record variable is NULL, instantiate it if it has a
* named composite type, else complain. (This won't change
* the logical state of the record: it's still NULL.)
*/
if (rec->erh == NULL)
instantiate_empty_record_variable(estate, rec);
/*
* Look up the field's properties if we have not already, or
* if the tuple descriptor ID changed since last time.
*/
if (unlikely(recfield->rectupledescid != rec->erh->er_tupdesc_id))
{
if (!expanded_record_lookup_field(rec->erh,
recfield->fieldname,
&recfield->finfo))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("record \"%s\" has no field \"%s\"",
rec->refname, recfield->fieldname)));
recfield->rectupledescid = rec->erh->er_tupdesc_id;
}
*typeId = recfield->finfo.ftypeid;
*typMod = recfield->finfo.ftypmod;
*collation = recfield->finfo.fcollation;
break;
}
default:
elog(ERROR, "unrecognized dtype: %d", datum->dtype);
*typeId = InvalidOid; /* keep compiler quiet */
*typMod = -1;
*collation = InvalidOid;
break;
}
}
/* ----------
* exec_eval_integer Evaluate an expression, coerce result to int4
*
* Note we do not do exec_eval_cleanup here; the caller must do it at
* some later point. (We do this because the caller may be holding the
* results of other, pass-by-reference, expression evaluations, such as
* an array value to be subscripted.)
* ----------
*/
static int
exec_eval_integer(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
bool *isNull)
{
Datum exprdatum;
Oid exprtypeid;
int32 exprtypmod;
exprdatum = exec_eval_expr(estate, expr, isNull, &exprtypeid, &exprtypmod);
exprdatum = exec_cast_value(estate, exprdatum, isNull,
exprtypeid, exprtypmod,
INT4OID, -1);
return DatumGetInt32(exprdatum);
}
/* ----------
* exec_eval_boolean Evaluate an expression, coerce result to bool
*
* Note we do not do exec_eval_cleanup here; the caller must do it at
* some later point.
* ----------
*/
static bool
exec_eval_boolean(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
bool *isNull)
{
Datum exprdatum;
Oid exprtypeid;
int32 exprtypmod;
exprdatum = exec_eval_expr(estate, expr, isNull, &exprtypeid, &exprtypmod);
exprdatum = exec_cast_value(estate, exprdatum, isNull,
exprtypeid, exprtypmod,
BOOLOID, -1);
return DatumGetBool(exprdatum);
}
/* ----------
* exec_eval_expr Evaluate an expression and return
* the result Datum, along with data type/typmod.
*
* NOTE: caller must do exec_eval_cleanup when done with the Datum.
* ----------
*/
static Datum
exec_eval_expr(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
bool *isNull,
Oid *rettype,
int32 *rettypmod)
{
Datum result = 0;
int rc;
Form_pg_attribute attr;
/*
* If first time through, create a plan for this expression.
*/
if (expr->plan == NULL)
exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK, true);
/*
* If this is a simple expression, bypass SPI and use the executor
* directly
*/
if (exec_eval_simple_expr(estate, expr,
&result, isNull, rettype, rettypmod))
return result;
/*
* Else do it the hard way via exec_run_select
*/
rc = exec_run_select(estate, expr, 2, NULL);
if (rc != SPI_OK_SELECT)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("query \"%s\" did not return data", expr->query)));
/*
* Check that the expression returns exactly one column...
*/
if (estate->eval_tuptable->tupdesc->natts != 1)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg_plural("query \"%s\" returned %d column",
"query \"%s\" returned %d columns",
estate->eval_tuptable->tupdesc->natts,
expr->query,
estate->eval_tuptable->tupdesc->natts)));
/*
* ... and get the column's datatype.
*/
attr = TupleDescAttr(estate->eval_tuptable->tupdesc, 0);
*rettype = attr->atttypid;
*rettypmod = attr->atttypmod;
/*
* If there are no rows selected, the result is a NULL of that type.
*/
if (estate->eval_processed == 0)
{
*isNull = true;
return (Datum) 0;
}
/*
* Check that the expression returned no more than one row.
*/
if (estate->eval_processed != 1)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("query \"%s\" returned more than one row",
expr->query)));
/*
* Return the single result Datum.
*/
return SPI_getbinval(estate->eval_tuptable->vals[0],
estate->eval_tuptable->tupdesc, 1, isNull);
}
/* ----------
* exec_run_select Execute a select query
* ----------
*/
static int
exec_run_select(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr, int64 maxtuples, Portal *portalP)
{
ParamListInfo paramLI;
int rc;
/*
* On the first call for this expression generate the plan.
*
* If we don't need to return a portal, then we're just going to execute
* the query once, which means it's OK to use a parallel plan, even if the
* number of rows being fetched is limited. If we do need to return a
* portal, the caller might do cursor operations, which parallel query
* can't support.
*/
if (expr->plan == NULL)
exec_prepare_plan(estate, expr,
portalP == NULL ? CURSOR_OPT_PARALLEL_OK : 0, true);
/*
* Set up ParamListInfo to pass to executor
*/
paramLI = setup_param_list(estate, expr);
/*
* If a portal was requested, put the query and paramlist into the portal
*/
if (portalP != NULL)
{
*portalP = SPI_cursor_open_with_paramlist(NULL, expr->plan,
paramLI,
estate->readonly_func);
if (*portalP == NULL)
elog(ERROR, "could not open implicit cursor for query \"%s\": %s",
expr->query, SPI_result_code_string(SPI_result));
exec_eval_cleanup(estate);
return SPI_OK_CURSOR;
}
/*
* Execute the query
*/
rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
estate->readonly_func, maxtuples);
if (rc != SPI_OK_SELECT)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("query \"%s\" is not a SELECT", expr->query)));
/* Save query results for eventual cleanup */
Assert(estate->eval_tuptable == NULL);
estate->eval_tuptable = SPI_tuptable;
estate->eval_processed = SPI_processed;
return rc;
}
/*
* exec_for_query --- execute body of FOR loop for each row from a portal
*
* Used by exec_stmt_fors, exec_stmt_forc and exec_stmt_dynfors
*/
static int
exec_for_query(PLpgSQL_execstate *estate, PLpgSQL_stmt_forq *stmt,
Portal portal, bool prefetch_ok)
{
PLpgSQL_variable *var;
SPITupleTable *tuptab;
bool found = false;
int rc = PLPGSQL_RC_OK;
uint64 previous_id = INVALID_TUPLEDESC_IDENTIFIER;
bool tupdescs_match = true;
uint64 n;
/* Fetch loop variable's datum entry */
var = (PLpgSQL_variable *) estate->datums[stmt->var->dno];
/*
* Make sure the portal doesn't get closed by the user statements we
* execute.
*/
PinPortal(portal);
/*
* Fetch the initial tuple(s). If prefetching is allowed then we grab a
* few more rows to avoid multiple trips through executor startup
* overhead.
*/
SPI_cursor_fetch(portal, true, prefetch_ok ? 10 : 1);
tuptab = SPI_tuptable;
n = SPI_processed;
/*
* If the query didn't return any rows, set the target to NULL and fall
* through with found = false.
*/
if (n == 0)
{
exec_move_row(estate, var, NULL, tuptab->tupdesc);
exec_eval_cleanup(estate);
}
else
found = true; /* processed at least one tuple */
/*
* Now do the loop
*/
while (n > 0)
{
uint64 i;
for (i = 0; i < n; i++)
{
/*
* Assign the tuple to the target. Here, because we know that all
* loop iterations should be assigning the same tupdesc, we can
* optimize away repeated creations of expanded records with
* identical tupdescs. Testing for changes of er_tupdesc_id is
* reliable even if the loop body contains assignments that
* replace the target's value entirely, because it's assigned from
* a process-global counter. The case where the tupdescs don't
* match could possibly be handled more efficiently than this
* coding does, but it's not clear extra effort is worthwhile.
*/
if (var->dtype == PLPGSQL_DTYPE_REC)
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) var;
if (rec->erh &&
rec->erh->er_tupdesc_id == previous_id &&
tupdescs_match)
{
/* Only need to assign a new tuple value */
expanded_record_set_tuple(rec->erh, tuptab->vals[i],
true, !estate->atomic);
}
else
{
/*
* First time through, or var's tupdesc changed in loop,
* or we have to do it the hard way because type coercion
* is needed.
*/
exec_move_row(estate, var,
tuptab->vals[i], tuptab->tupdesc);
/*
* Check to see if physical assignment is OK next time.
* Once the tupdesc comparison has failed once, we don't
* bother rechecking in subsequent loop iterations.
*/
if (tupdescs_match)
{
tupdescs_match =
(rec->rectypeid == RECORDOID ||
rec->rectypeid == tuptab->tupdesc->tdtypeid ||
compatible_tupdescs(tuptab->tupdesc,
expanded_record_get_tupdesc(rec->erh)));
}
previous_id = rec->erh->er_tupdesc_id;
}
}
else
exec_move_row(estate, var, tuptab->vals[i], tuptab->tupdesc);
exec_eval_cleanup(estate);
/*
* Execute the statements
*/
rc = exec_stmts(estate, stmt->body);
LOOP_RC_PROCESSING(stmt->label, goto loop_exit);
}
SPI_freetuptable(tuptab);
/*
* Fetch more tuples. If prefetching is allowed, grab 50 at a time.
*/
SPI_cursor_fetch(portal, true, prefetch_ok ? 50 : 1);
tuptab = SPI_tuptable;
n = SPI_processed;
}
loop_exit:
/*
* Release last group of tuples (if any)
*/
SPI_freetuptable(tuptab);
UnpinPortal(portal);
/*
* Set the FOUND variable to indicate the result of executing the loop
* (namely, whether we looped one or more times). This must be set last so
* that it does not interfere with the value of the FOUND variable inside
* the loop processing itself.
*/
exec_set_found(estate, found);
return rc;
}
/* ----------
* exec_eval_simple_expr - Evaluate a simple expression returning
* a Datum by directly calling ExecEvalExpr().
*
* If successful, store results into *result, *isNull, *rettype, *rettypmod
* and return true. If the expression cannot be handled by simple evaluation,
* return false.
*
* Because we only store one execution tree for a simple expression, we
* can't handle recursion cases. So, if we see the tree is already busy
* with an evaluation in the current xact, we just return false and let the
* caller run the expression the hard way. (Other alternatives such as
* creating a new tree for a recursive call either introduce memory leaks,
* or add enough bookkeeping to be doubtful wins anyway.) Another case that
* is covered by the expr_simple_in_use test is where a previous execution
* of the tree was aborted by an error: the tree may contain bogus state
* so we dare not re-use it.
*
* It is possible that we'd need to replan a simple expression; for example,
* someone might redefine a SQL function that had been inlined into the simple
* expression. That cannot cause a simple expression to become non-simple (or
* vice versa), but we do have to handle replacing the expression tree.
* Fortunately it's normally inexpensive to call SPI_plan_get_cached_plan for
* a simple expression.
*
* Note: if pass-by-reference, the result is in the eval_mcontext.
* It will be freed when exec_eval_cleanup is done.
* ----------
*/
static bool
exec_eval_simple_expr(PLpgSQL_execstate *estate,
PLpgSQL_expr *expr,
Datum *result,
bool *isNull,
Oid *rettype,
int32 *rettypmod)
{
ExprContext *econtext = estate->eval_econtext;
LocalTransactionId curlxid = MyProc->lxid;
CachedPlan *cplan;
void *save_setup_arg;
MemoryContext oldcontext;
/*
* Forget it if expression wasn't simple before.
*/
if (expr->expr_simple_expr == NULL)
return false;
/*
* If expression is in use in current xact, don't touch it.
*/
if (expr->expr_simple_in_use && expr->expr_simple_lxid == curlxid)
return false;
/*
* Revalidate cached plan, so that we will notice if it became stale. (We
* need to hold a refcount while using the plan, anyway.) If replanning
* is needed, do that work in the eval_mcontext.
*/
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
cplan = SPI_plan_get_cached_plan(expr->plan);
MemoryContextSwitchTo(oldcontext);
/*
* We can't get a failure here, because the number of CachedPlanSources in
* the SPI plan can't change from what exec_simple_check_plan saw; it's a
* property of the raw parsetree generated from the query text.
*/
Assert(cplan != NULL);
/* If it got replanned, update our copy of the simple expression */
if (cplan->generation != expr->expr_simple_generation)
{
exec_save_simple_expr(expr, cplan);
/* better recheck r/w safety, as it could change due to inlining */
if (expr->rwparam >= 0)
exec_check_rw_parameter(expr, expr->rwparam);
}
/*
* Pass back previously-determined result type.
*/
*rettype = expr->expr_simple_type;
*rettypmod = expr->expr_simple_typmod;
/*
* Set up ParamListInfo to pass to executor. For safety, save and restore
* estate->paramLI->parserSetupArg around our use of the param list.
*/
save_setup_arg = estate->paramLI->parserSetupArg;
econtext->ecxt_param_list_info = setup_param_list(estate, expr);
/*
* Prepare the expression for execution, if it's not been done already in
* the current transaction. (This will be forced to happen if we called
* exec_save_simple_expr above.)
*/
if (expr->expr_simple_lxid != curlxid)
{
oldcontext = MemoryContextSwitchTo(estate->simple_eval_estate->es_query_cxt);
expr->expr_simple_state =
ExecInitExprWithParams(expr->expr_simple_expr,
econtext->ecxt_param_list_info);
expr->expr_simple_in_use = false;
expr->expr_simple_lxid = curlxid;
MemoryContextSwitchTo(oldcontext);
}
/*
* We have to do some of the things SPI_execute_plan would do, in
* particular advance the snapshot if we are in a non-read-only function.
* Without this, stable functions within the expression would fail to see
* updates made so far by our own function.
*/
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
if (!estate->readonly_func)
{
CommandCounterIncrement();
PushActiveSnapshot(GetTransactionSnapshot());
}
/*
* Mark expression as busy for the duration of the ExecEvalExpr call.
*/
expr->expr_simple_in_use = true;
/*
* Finally we can call the executor to evaluate the expression
*/
*result = ExecEvalExpr(expr->expr_simple_state,
econtext,
isNull);
/* Assorted cleanup */
expr->expr_simple_in_use = false;
econtext->ecxt_param_list_info = NULL;
estate->paramLI->parserSetupArg = save_setup_arg;
if (!estate->readonly_func)
PopActiveSnapshot();
MemoryContextSwitchTo(oldcontext);
/*
* Now we can release our refcount on the cached plan.
*/
ReleaseCachedPlan(cplan, true);
/*
* That's it.
*/
return true;
}
/*
* Create a ParamListInfo to pass to SPI
*
* We use a single ParamListInfo struct for all SPI calls made from this
* estate; it contains no per-param data, just hook functions, so it's
* effectively read-only for SPI.
*
* An exception from pure read-only-ness is that the parserSetupArg points
* to the specific PLpgSQL_expr being evaluated. This is not an issue for
* statement-level callers, but lower-level callers must save and restore
* estate->paramLI->parserSetupArg just in case there's an active evaluation
* at an outer call level. (A plausible alternative design would be to
* create a ParamListInfo struct for each PLpgSQL_expr, but for the moment
* that seems like a waste of memory.)
*/
static ParamListInfo
setup_param_list(PLpgSQL_execstate *estate, PLpgSQL_expr *expr)
{
ParamListInfo paramLI;
/*
* We must have created the SPIPlan already (hence, query text has been
* parsed/analyzed at least once); else we cannot rely on expr->paramnos.
*/
Assert(expr->plan != NULL);
/*
* We only need a ParamListInfo if the expression has parameters. In
* principle we should test with bms_is_empty(), but we use a not-null
* test because it's faster. In current usage bits are never removed from
* expr->paramnos, only added, so this test is correct anyway.
*/
if (expr->paramnos)
{
/* Use the common ParamListInfo */
paramLI = estate->paramLI;
/*
* Set up link to active expr where the hook functions can find it.
* Callers must save and restore parserSetupArg if there is any chance
* that they are interrupting an active use of parameters.
*/
paramLI->parserSetupArg = (void *) expr;
/*
* Also make sure this is set before parser hooks need it. There is
* no need to save and restore, since the value is always correct once
* set. (Should be set already, but let's be sure.)
*/
expr->func = estate->func;
}
else
{
/*
* Expression requires no parameters. Be sure we represent this case
* as a NULL ParamListInfo, so that plancache.c knows there is no
* point in a custom plan.
*/
paramLI = NULL;
}
return paramLI;
}
/*
* plpgsql_param_fetch paramFetch callback for dynamic parameter fetch
*
* We always use the caller's workspace to construct the returned struct.
*
* Note: this is no longer used during query execution. It is used during
* planning (with speculative == true) and when the ParamListInfo we supply
* to the executor is copied into a cursor portal or transferred to a
* parallel child process.
*/
static ParamExternData *
plpgsql_param_fetch(ParamListInfo params,
int paramid, bool speculative,
ParamExternData *prm)
{
int dno;
PLpgSQL_execstate *estate;
PLpgSQL_expr *expr;
PLpgSQL_datum *datum;
bool ok = true;
int32 prmtypmod;
/* paramid's are 1-based, but dnos are 0-based */
dno = paramid - 1;
Assert(dno >= 0 && dno < params->numParams);
/* fetch back the hook data */
estate = (PLpgSQL_execstate *) params->paramFetchArg;
expr = (PLpgSQL_expr *) params->parserSetupArg;
Assert(params->numParams == estate->ndatums);
/* now we can access the target datum */
datum = estate->datums[dno];
/*
* Since copyParamList() or SerializeParamList() will try to materialize
* every single parameter slot, it's important to return a dummy param
* when asked for a datum that's not supposed to be used by this SQL
* expression. Otherwise we risk failures in exec_eval_datum(), or
* copying a lot more data than necessary.
*/
if (!bms_is_member(dno, expr->paramnos))
ok = false;
/*
* If the access is speculative, we prefer to return no data rather than
* to fail in exec_eval_datum(). Check the likely failure cases.
*/
else if (speculative)
{
switch (datum->dtype)
{
case PLPGSQL_DTYPE_VAR:
case PLPGSQL_DTYPE_PROMISE:
/* always safe */
break;
case PLPGSQL_DTYPE_ROW:
/* should be safe in all interesting cases */
break;
case PLPGSQL_DTYPE_REC:
/* always safe (might return NULL, that's fine) */
break;
case PLPGSQL_DTYPE_RECFIELD:
{
PLpgSQL_recfield *recfield = (PLpgSQL_recfield *) datum;
PLpgSQL_rec *rec;
rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
/*
* If record variable is NULL, don't risk anything.
*/
if (rec->erh == NULL)
ok = false;
/*
* Look up the field's properties if we have not already,
* or if the tuple descriptor ID changed since last time.
*/
else if (unlikely(recfield->rectupledescid != rec->erh->er_tupdesc_id))
{
if (expanded_record_lookup_field(rec->erh,
recfield->fieldname,
&recfield->finfo))
recfield->rectupledescid = rec->erh->er_tupdesc_id;
else
ok = false;
}
break;
}
default:
ok = false;
break;
}
}
/* Return "no such parameter" if not ok */
if (!ok)
{
prm->value = (Datum) 0;
prm->isnull = true;
prm->pflags = 0;
prm->ptype = InvalidOid;
return prm;
}
/* OK, evaluate the value and store into the return struct */
exec_eval_datum(estate, datum,
&prm->ptype, &prmtypmod,
&prm->value, &prm->isnull);
/* We can always mark params as "const" for executor's purposes */
prm->pflags = PARAM_FLAG_CONST;
/*
* If it's a read/write expanded datum, convert reference to read-only,
* unless it's safe to pass as read-write.
*/
if (dno != expr->rwparam)
{
if (datum->dtype == PLPGSQL_DTYPE_VAR)
prm->value = MakeExpandedObjectReadOnly(prm->value,
prm->isnull,
((PLpgSQL_var *) datum)->datatype->typlen);
else if (datum->dtype == PLPGSQL_DTYPE_REC)
prm->value = MakeExpandedObjectReadOnly(prm->value,
prm->isnull,
-1);
}
return prm;
}
/*
* plpgsql_param_compile paramCompile callback for plpgsql parameters
*/
static void
plpgsql_param_compile(ParamListInfo params, Param *param,
ExprState *state,
Datum *resv, bool *resnull)
{
PLpgSQL_execstate *estate;
PLpgSQL_expr *expr;
int dno;
PLpgSQL_datum *datum;
ExprEvalStep scratch;
/* fetch back the hook data */
estate = (PLpgSQL_execstate *) params->paramFetchArg;
expr = (PLpgSQL_expr *) params->parserSetupArg;
/* paramid's are 1-based, but dnos are 0-based */
dno = param->paramid - 1;
Assert(dno >= 0 && dno < estate->ndatums);
/* now we can access the target datum */
datum = estate->datums[dno];
scratch.opcode = EEOP_PARAM_CALLBACK;
scratch.resvalue = resv;
scratch.resnull = resnull;
/*
* Select appropriate eval function. It seems worth special-casing
* DTYPE_VAR and DTYPE_RECFIELD for performance. Also, we can determine
* in advance whether MakeExpandedObjectReadOnly() will be required.
* Currently, only VAR/PROMISE and REC datums could contain read/write
* expanded objects.
*/
if (datum->dtype == PLPGSQL_DTYPE_VAR)
{
if (dno != expr->rwparam &&
((PLpgSQL_var *) datum)->datatype->typlen == -1)
scratch.d.cparam.paramfunc = plpgsql_param_eval_var_ro;
else
scratch.d.cparam.paramfunc = plpgsql_param_eval_var;
}
else if (datum->dtype == PLPGSQL_DTYPE_RECFIELD)
scratch.d.cparam.paramfunc = plpgsql_param_eval_recfield;
else if (datum->dtype == PLPGSQL_DTYPE_PROMISE)
{
if (dno != expr->rwparam &&
((PLpgSQL_var *) datum)->datatype->typlen == -1)
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic_ro;
else
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic;
}
else if (datum->dtype == PLPGSQL_DTYPE_REC &&
dno != expr->rwparam)
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic_ro;
else
scratch.d.cparam.paramfunc = plpgsql_param_eval_generic;
/*
* Note: it's tempting to use paramarg to store the estate pointer and
* thereby save an indirection or two in the eval functions. But that
* doesn't work because the compiled expression might be used with
* different estates for the same PL/pgSQL function.
*/
scratch.d.cparam.paramarg = NULL;
scratch.d.cparam.paramid = param->paramid;
scratch.d.cparam.paramtype = param->paramtype;
ExprEvalPushStep(state, &scratch);
}
/*
* plpgsql_param_eval_var evaluation of EEOP_PARAM_CALLBACK step
*
* This is specialized to the case of DTYPE_VAR variables for which
* we do not need to invoke MakeExpandedObjectReadOnly.
*/
static void
plpgsql_param_eval_var(ExprState *state, ExprEvalStep *op,
ExprContext *econtext)
{
ParamListInfo params;
PLpgSQL_execstate *estate;
int dno = op->d.cparam.paramid - 1;
PLpgSQL_var *var;
/* fetch back the hook data */
params = econtext->ecxt_param_list_info;
estate = (PLpgSQL_execstate *) params->paramFetchArg;
Assert(dno >= 0 && dno < estate->ndatums);
/* now we can access the target datum */
var = (PLpgSQL_var *) estate->datums[dno];
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
/* inlined version of exec_eval_datum() */
*op->resvalue = var->value;
*op->resnull = var->isnull;
/* safety check -- an assertion should be sufficient */
Assert(var->datatype->typoid == op->d.cparam.paramtype);
}
/*
* plpgsql_param_eval_var_ro evaluation of EEOP_PARAM_CALLBACK step
*
* This is specialized to the case of DTYPE_VAR variables for which
* we need to invoke MakeExpandedObjectReadOnly.
*/
static void
plpgsql_param_eval_var_ro(ExprState *state, ExprEvalStep *op,
ExprContext *econtext)
{
ParamListInfo params;
PLpgSQL_execstate *estate;
int dno = op->d.cparam.paramid - 1;
PLpgSQL_var *var;
/* fetch back the hook data */
params = econtext->ecxt_param_list_info;
estate = (PLpgSQL_execstate *) params->paramFetchArg;
Assert(dno >= 0 && dno < estate->ndatums);
/* now we can access the target datum */
var = (PLpgSQL_var *) estate->datums[dno];
Assert(var->dtype == PLPGSQL_DTYPE_VAR);
/*
* Inlined version of exec_eval_datum() ... and while we're at it, force
* expanded datums to read-only.
*/
*op->resvalue = MakeExpandedObjectReadOnly(var->value,
var->isnull,
-1);
*op->resnull = var->isnull;
/* safety check -- an assertion should be sufficient */
Assert(var->datatype->typoid == op->d.cparam.paramtype);
}
/*
* plpgsql_param_eval_recfield evaluation of EEOP_PARAM_CALLBACK step
*
* This is specialized to the case of DTYPE_RECFIELD variables, for which
* we never need to invoke MakeExpandedObjectReadOnly.
*/
static void
plpgsql_param_eval_recfield(ExprState *state, ExprEvalStep *op,
ExprContext *econtext)
{
ParamListInfo params;
PLpgSQL_execstate *estate;
int dno = op->d.cparam.paramid - 1;
PLpgSQL_recfield *recfield;
PLpgSQL_rec *rec;
ExpandedRecordHeader *erh;
/* fetch back the hook data */
params = econtext->ecxt_param_list_info;
estate = (PLpgSQL_execstate *) params->paramFetchArg;
Assert(dno >= 0 && dno < estate->ndatums);
/* now we can access the target datum */
recfield = (PLpgSQL_recfield *) estate->datums[dno];
Assert(recfield->dtype == PLPGSQL_DTYPE_RECFIELD);
/* inline the relevant part of exec_eval_datum */
rec = (PLpgSQL_rec *) (estate->datums[recfield->recparentno]);
erh = rec->erh;
/*
* If record variable is NULL, instantiate it if it has a named composite
* type, else complain. (This won't change the logical state of the
* record: it's still NULL.)
*/
if (erh == NULL)
{
instantiate_empty_record_variable(estate, rec);
erh = rec->erh;
}
/*
* Look up the field's properties if we have not already, or if the tuple
* descriptor ID changed since last time.
*/
if (unlikely(recfield->rectupledescid != erh->er_tupdesc_id))
{
if (!expanded_record_lookup_field(erh,
recfield->fieldname,
&recfield->finfo))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("record \"%s\" has no field \"%s\"",
rec->refname, recfield->fieldname)));
recfield->rectupledescid = erh->er_tupdesc_id;
}
/* OK to fetch the field value. */
*op->resvalue = expanded_record_get_field(erh,
recfield->finfo.fnumber,
op->resnull);
/* safety check -- needed for, eg, record fields */
if (unlikely(recfield->finfo.ftypeid != op->d.cparam.paramtype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("type of parameter %d (%s) does not match that when preparing the plan (%s)",
op->d.cparam.paramid,
format_type_be(recfield->finfo.ftypeid),
format_type_be(op->d.cparam.paramtype))));
}
/*
* plpgsql_param_eval_generic evaluation of EEOP_PARAM_CALLBACK step
*
* This handles all variable types, but assumes we do not need to invoke
* MakeExpandedObjectReadOnly.
*/
static void
plpgsql_param_eval_generic(ExprState *state, ExprEvalStep *op,
ExprContext *econtext)
{
ParamListInfo params;
PLpgSQL_execstate *estate;
int dno = op->d.cparam.paramid - 1;
PLpgSQL_datum *datum;
Oid datumtype;
int32 datumtypmod;
/* fetch back the hook data */
params = econtext->ecxt_param_list_info;
estate = (PLpgSQL_execstate *) params->paramFetchArg;
Assert(dno >= 0 && dno < estate->ndatums);
/* now we can access the target datum */
datum = estate->datums[dno];
/* fetch datum's value */
exec_eval_datum(estate, datum,
&datumtype, &datumtypmod,
op->resvalue, op->resnull);
/* safety check -- needed for, eg, record fields */
if (unlikely(datumtype != op->d.cparam.paramtype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("type of parameter %d (%s) does not match that when preparing the plan (%s)",
op->d.cparam.paramid,
format_type_be(datumtype),
format_type_be(op->d.cparam.paramtype))));
}
/*
* plpgsql_param_eval_generic_ro evaluation of EEOP_PARAM_CALLBACK step
*
* This handles all variable types, but assumes we need to invoke
* MakeExpandedObjectReadOnly (hence, variable must be of a varlena type).
*/
static void
plpgsql_param_eval_generic_ro(ExprState *state, ExprEvalStep *op,
ExprContext *econtext)
{
ParamListInfo params;
PLpgSQL_execstate *estate;
int dno = op->d.cparam.paramid - 1;
PLpgSQL_datum *datum;
Oid datumtype;
int32 datumtypmod;
/* fetch back the hook data */
params = econtext->ecxt_param_list_info;
estate = (PLpgSQL_execstate *) params->paramFetchArg;
Assert(dno >= 0 && dno < estate->ndatums);
/* now we can access the target datum */
datum = estate->datums[dno];
/* fetch datum's value */
exec_eval_datum(estate, datum,
&datumtype, &datumtypmod,
op->resvalue, op->resnull);
/* safety check -- needed for, eg, record fields */
if (unlikely(datumtype != op->d.cparam.paramtype))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("type of parameter %d (%s) does not match that when preparing the plan (%s)",
op->d.cparam.paramid,
format_type_be(datumtype),
format_type_be(op->d.cparam.paramtype))));
/* force the value to read-only */
*op->resvalue = MakeExpandedObjectReadOnly(*op->resvalue,
*op->resnull,
-1);
}
/*
* exec_move_row Move one tuple's values into a record or row
*
* tup and tupdesc may both be NULL if we're just assigning an indeterminate
* composite NULL to the target. Alternatively, can have tup be NULL and
* tupdesc not NULL, in which case we assign a row of NULLs to the target.
*
* Since this uses the mcontext for workspace, caller should eventually call
* exec_eval_cleanup to prevent long-term memory leaks.
*/
static void
exec_move_row(PLpgSQL_execstate *estate,
PLpgSQL_variable *target,
HeapTuple tup, TupleDesc tupdesc)
{
ExpandedRecordHeader *newerh = NULL;
/*
* If target is RECORD, we may be able to avoid field-by-field processing.
*/
if (target->dtype == PLPGSQL_DTYPE_REC)
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) target;
/*
* If we have no source tupdesc, just set the record variable to NULL.
* (If we have a source tupdesc but not a tuple, we'll set the
* variable to a row of nulls, instead. This is odd perhaps, but
* backwards compatible.)
*/
if (tupdesc == NULL)
{
if (rec->datatype &&
rec->datatype->typtype == TYPTYPE_DOMAIN)
{
/*
* If it's a composite domain, NULL might not be a legal
* value, so we instead need to make an empty expanded record
* and ensure that domain type checking gets done. If there
* is already an expanded record, piggyback on its lookups.
*/
newerh = make_expanded_record_for_rec(estate, rec,
NULL, rec->erh);
expanded_record_set_tuple(newerh, NULL, false, false);
assign_record_var(estate, rec, newerh);
}
else
{
/* Just clear it to NULL */
if (rec->erh)
DeleteExpandedObject(ExpandedRecordGetDatum(rec->erh));
rec->erh = NULL;
}
return;
}
/*
* Build a new expanded record with appropriate tupdesc.
*/
newerh = make_expanded_record_for_rec(estate, rec, tupdesc, NULL);
/*
* If the rowtypes match, or if we have no tuple anyway, we can
* complete the assignment without field-by-field processing.
*
* The tests here are ordered more or less in order of cheapness. We
* can easily detect it will work if the target is declared RECORD or
* has the same typeid as the source. But when assigning from a query
* result, it's common to have a source tupdesc that's labeled RECORD
* but is actually physically compatible with a named-composite-type
* target, so it's worth spending extra cycles to check for that.
*/
if (rec->rectypeid == RECORDOID ||
rec->rectypeid == tupdesc->tdtypeid ||
!HeapTupleIsValid(tup) ||
compatible_tupdescs(tupdesc, expanded_record_get_tupdesc(newerh)))
{
if (!HeapTupleIsValid(tup))
{
/* No data, so force the record into all-nulls state */
deconstruct_expanded_record(newerh);
}
else
{
/* No coercion is needed, so just assign the row value */
expanded_record_set_tuple(newerh, tup, true, !estate->atomic);
}
/* Complete the assignment */
assign_record_var(estate, rec, newerh);
return;
}
}
/*
* Otherwise, deconstruct the tuple and do field-by-field assignment,
* using exec_move_row_from_fields.
*/
if (tupdesc && HeapTupleIsValid(tup))
{
int td_natts = tupdesc->natts;
Datum *values;
bool *nulls;
Datum values_local[64];
bool nulls_local[64];
/*
* Need workspace arrays. If td_natts is small enough, use local
* arrays to save doing a palloc. Even if it's not small, we can
* allocate both the Datum and isnull arrays in one palloc chunk.
*/
if (td_natts <= lengthof(values_local))
{
values = values_local;
nulls = nulls_local;
}
else
{
char *chunk;
chunk = eval_mcontext_alloc(estate,
td_natts * (sizeof(Datum) + sizeof(bool)));
values = (Datum *) chunk;
nulls = (bool *) (chunk + td_natts * sizeof(Datum));
}
heap_deform_tuple(tup, tupdesc, values, nulls);
exec_move_row_from_fields(estate, target, newerh,
values, nulls, tupdesc);
}
else
{
/*
* Assign all-nulls.
*/
exec_move_row_from_fields(estate, target, newerh,
NULL, NULL, NULL);
}
}
/*
* Build an expanded record object suitable for assignment to "rec".
*
* Caller must supply either a source tuple descriptor or a source expanded
* record (not both). If the record variable has declared type RECORD,
* it'll adopt the source's rowtype. Even if it doesn't, we may be able to
* piggyback on a source expanded record to save a typcache lookup.
*
* Caller must fill the object with data, then do assign_record_var().
*
* The new record is initially put into the mcontext, so it will be cleaned up
* if we fail before reaching assign_record_var().
*/
static ExpandedRecordHeader *
make_expanded_record_for_rec(PLpgSQL_execstate *estate,
PLpgSQL_rec *rec,
TupleDesc srctupdesc,
ExpandedRecordHeader *srcerh)
{
ExpandedRecordHeader *newerh;
MemoryContext mcontext = get_eval_mcontext(estate);
if (rec->rectypeid != RECORDOID)
{
/*
* New record must be of desired type, but maybe srcerh has already
* done all the same lookups.
*/
if (srcerh && rec->rectypeid == srcerh->er_decltypeid)
newerh = make_expanded_record_from_exprecord(srcerh,
mcontext);
else
newerh = make_expanded_record_from_typeid(rec->rectypeid, -1,
mcontext);
}
else
{
/*
* We'll adopt the input tupdesc. We can still use
* make_expanded_record_from_exprecord, if srcerh isn't a composite
* domain. (If it is, we effectively adopt its base type.)
*/
if (srcerh && !ExpandedRecordIsDomain(srcerh))
newerh = make_expanded_record_from_exprecord(srcerh,
mcontext);
else
{
if (!srctupdesc)
srctupdesc = expanded_record_get_tupdesc(srcerh);
newerh = make_expanded_record_from_tupdesc(srctupdesc,
mcontext);
}
}
return newerh;
}
/*
* exec_move_row_from_fields Move arrays of field values into a record or row
*
* When assigning to a record, the caller must have already created a suitable
* new expanded record object, newerh. Pass NULL when assigning to a row.
*
* tupdesc describes the input row, which might have different column
* types and/or different dropped-column positions than the target.
* values/nulls/tupdesc can all be NULL if we just want to assign nulls to
* all fields of the record or row.
*
* Since this uses the mcontext for workspace, caller should eventually call
* exec_eval_cleanup to prevent long-term memory leaks.
*/
static void
exec_move_row_from_fields(PLpgSQL_execstate *estate,
PLpgSQL_variable *target,
ExpandedRecordHeader *newerh,
Datum *values, bool *nulls,
TupleDesc tupdesc)
{
int td_natts = tupdesc ? tupdesc->natts : 0;
int fnum;
int anum;
int strict_multiassignment_level = 0;
/*
* The extra check strict strict_multi_assignment can be active, only when
* input tupdesc is specified.
*/
if (tupdesc != NULL)
{
if (plpgsql_extra_errors & PLPGSQL_XCHECK_STRICTMULTIASSIGNMENT)
strict_multiassignment_level = ERROR;
else if (plpgsql_extra_warnings & PLPGSQL_XCHECK_STRICTMULTIASSIGNMENT)
strict_multiassignment_level = WARNING;
}
/* Handle RECORD-target case */
if (target->dtype == PLPGSQL_DTYPE_REC)
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) target;
TupleDesc var_tupdesc;
Datum newvalues_local[64];
bool newnulls_local[64];
Assert(newerh != NULL); /* caller must have built new object */
var_tupdesc = expanded_record_get_tupdesc(newerh);
/*
* Coerce field values if needed. This might involve dealing with
* different sets of dropped columns and/or coercing individual column
* types. That's sort of a pain, but historically plpgsql has allowed
* it, so we preserve the behavior. However, it's worth a quick check
* to see if the tupdescs are identical. (Since expandedrecord.c
* prefers to use refcounted tupdescs from the typcache, expanded
* records with the same rowtype will have pointer-equal tupdescs.)
*/
if (var_tupdesc != tupdesc)
{
int vtd_natts = var_tupdesc->natts;
Datum *newvalues;
bool *newnulls;
/*
* Need workspace arrays. If vtd_natts is small enough, use local
* arrays to save doing a palloc. Even if it's not small, we can
* allocate both the Datum and isnull arrays in one palloc chunk.
*/
if (vtd_natts <= lengthof(newvalues_local))
{
newvalues = newvalues_local;
newnulls = newnulls_local;
}
else
{
char *chunk;
chunk = eval_mcontext_alloc(estate,
vtd_natts * (sizeof(Datum) + sizeof(bool)));
newvalues = (Datum *) chunk;
newnulls = (bool *) (chunk + vtd_natts * sizeof(Datum));
}
/* Walk over destination columns */
anum = 0;
for (fnum = 0; fnum < vtd_natts; fnum++)
{
Form_pg_attribute attr = TupleDescAttr(var_tupdesc, fnum);
Datum value;
bool isnull;
Oid valtype;
int32 valtypmod;
if (attr->attisdropped)
{
/* expanded_record_set_fields should ignore this column */
continue; /* skip dropped column in record */
}
while (anum < td_natts &&
TupleDescAttr(tupdesc, anum)->attisdropped)
anum++; /* skip dropped column in tuple */
if (anum < td_natts)
{
value = values[anum];
isnull = nulls[anum];
valtype = TupleDescAttr(tupdesc, anum)->atttypid;
valtypmod = TupleDescAttr(tupdesc, anum)->atttypmod;
anum++;
}
else
{
/* no source for destination column */
value = (Datum) 0;
isnull = true;
valtype = UNKNOWNOID;
valtypmod = -1;
/* When source value is missing */
if (strict_multiassignment_level)
ereport(strict_multiassignment_level,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("number of source and target fields in assignment does not match"),
/* translator: %s represents a name of an extra check */
errdetail("%s check of %s is active.",
"strict_multi_assignment",
strict_multiassignment_level == ERROR ? "extra_errors" :
"extra_warnings"),
errhint("Make sure the query returns the exact list of columns.")));
}
/* Cast the new value to the right type, if needed. */
newvalues[fnum] = exec_cast_value(estate,
value,
&isnull,
valtype,
valtypmod,
attr->atttypid,
attr->atttypmod);
newnulls[fnum] = isnull;
}
/*
* When strict_multiassignment extra check is active, then ensure
* there are no unassigned source attributes.
*/
if (strict_multiassignment_level && anum < td_natts)
{
/* skip dropped columns in the source descriptor */
while (anum < td_natts &&
TupleDescAttr(tupdesc, anum)->attisdropped)
anum++;
if (anum < td_natts)
ereport(strict_multiassignment_level,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("number of source and target fields in assignment does not match"),
/* translator: %s represents a name of an extra check */
errdetail("%s check of %s is active.",
"strict_multi_assignment",
strict_multiassignment_level == ERROR ? "extra_errors" :
"extra_warnings"),
errhint("Make sure the query returns the exact list of columns.")));
}
values = newvalues;
nulls = newnulls;
}
/* Insert the coerced field values into the new expanded record */
expanded_record_set_fields(newerh, values, nulls, !estate->atomic);
/* Complete the assignment */
assign_record_var(estate, rec, newerh);
return;
}
/* newerh should not have been passed in non-RECORD cases */
Assert(newerh == NULL);
/*
* For a row, we assign the individual field values to the variables the
* row points to.
*
* NOTE: both this code and the record code above silently ignore extra
* columns in the source and assume NULL for missing columns. This is
* pretty dubious but it's the historical behavior.
*
* If we have no input data at all, we'll assign NULL to all columns of
* the row variable.
*/
if (target->dtype == PLPGSQL_DTYPE_ROW)
{
PLpgSQL_row *row = (PLpgSQL_row *) target;
anum = 0;
for (fnum = 0; fnum < row->nfields; fnum++)
{
PLpgSQL_var *var;
Datum value;
bool isnull;
Oid valtype;
int32 valtypmod;
var = (PLpgSQL_var *) (estate->datums[row->varnos[fnum]]);
while (anum < td_natts &&
TupleDescAttr(tupdesc, anum)->attisdropped)
anum++; /* skip dropped column in tuple */
if (anum < td_natts)
{
value = values[anum];
isnull = nulls[anum];
valtype = TupleDescAttr(tupdesc, anum)->atttypid;
valtypmod = TupleDescAttr(tupdesc, anum)->atttypmod;
anum++;
}
else
{
/* no source for destination column */
value = (Datum) 0;
isnull = true;
valtype = UNKNOWNOID;
valtypmod = -1;
if (strict_multiassignment_level)
ereport(strict_multiassignment_level,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("number of source and target fields in assignment does not match"),
/* translator: %s represents a name of an extra check */
errdetail("%s check of %s is active.",
"strict_multi_assignment",
strict_multiassignment_level == ERROR ? "extra_errors" :
"extra_warnings"),
errhint("Make sure the query returns the exact list of columns.")));
}
exec_assign_value(estate, (PLpgSQL_datum *) var,
value, isnull, valtype, valtypmod);
}
/*
* When strict_multiassignment extra check is active, ensure there are
* no unassigned source attributes.
*/
if (strict_multiassignment_level && anum < td_natts)
{
while (anum < td_natts &&
TupleDescAttr(tupdesc, anum)->attisdropped)
anum++; /* skip dropped column in tuple */
if (anum < td_natts)
ereport(strict_multiassignment_level,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("number of source and target fields in assignment does not match"),
/* translator: %s represents a name of an extra check */
errdetail("%s check of %s is active.",
"strict_multi_assignment",
strict_multiassignment_level == ERROR ? "extra_errors" :
"extra_warnings"),
errhint("Make sure the query returns the exact list of columns.")));
}
return;
}
elog(ERROR, "unsupported target type: %d", target->dtype);
}
/*
* compatible_tupdescs: detect whether two tupdescs are physically compatible
*
* TRUE indicates that a tuple satisfying src_tupdesc can be used directly as
* a value for a composite variable using dst_tupdesc.
*/
static bool
compatible_tupdescs(TupleDesc src_tupdesc, TupleDesc dst_tupdesc)
{
int i;
/* Possibly we could allow src_tupdesc to have extra columns? */
if (dst_tupdesc->natts != src_tupdesc->natts)
return false;
for (i = 0; i < dst_tupdesc->natts; i++)
{
Form_pg_attribute dattr = TupleDescAttr(dst_tupdesc, i);
Form_pg_attribute sattr = TupleDescAttr(src_tupdesc, i);
if (dattr->attisdropped != sattr->attisdropped)
return false;
if (!dattr->attisdropped)
{
/* Normal columns must match by type and typmod */
if (dattr->atttypid != sattr->atttypid ||
(dattr->atttypmod >= 0 &&
dattr->atttypmod != sattr->atttypmod))
return false;
}
else
{
/* Dropped columns are OK as long as length/alignment match */
if (dattr->attlen != sattr->attlen ||
dattr->attalign != sattr->attalign)
return false;
}
}
return true;
}
/* ----------
* make_tuple_from_row Make a tuple from the values of a row object
*
* A NULL return indicates rowtype mismatch; caller must raise suitable error
*
* The result tuple is freshly palloc'd in caller's context. Some junk
* may be left behind in eval_mcontext, too.
* ----------
*/
static HeapTuple
make_tuple_from_row(PLpgSQL_execstate *estate,
PLpgSQL_row *row,
TupleDesc tupdesc)
{
int natts = tupdesc->natts;
HeapTuple tuple;
Datum *dvalues;
bool *nulls;
int i;
if (natts != row->nfields)
return NULL;
dvalues = (Datum *) eval_mcontext_alloc0(estate, natts * sizeof(Datum));
nulls = (bool *) eval_mcontext_alloc(estate, natts * sizeof(bool));
for (i = 0; i < natts; i++)
{
Oid fieldtypeid;
int32 fieldtypmod;
if (TupleDescAttr(tupdesc, i)->attisdropped)
{
nulls[i] = true; /* leave the column as null */
continue;
}
exec_eval_datum(estate, estate->datums[row->varnos[i]],
&fieldtypeid, &fieldtypmod,
&dvalues[i], &nulls[i]);
if (fieldtypeid != TupleDescAttr(tupdesc, i)->atttypid)
return NULL;
/* XXX should we insist on typmod match, too? */
}
tuple = heap_form_tuple(tupdesc, dvalues, nulls);
return tuple;
}
/*
* deconstruct_composite_datum extract tuple+tupdesc from composite Datum
*
* The caller must supply a HeapTupleData variable, in which we set up a
* tuple header pointing to the composite datum's body. To make the tuple
* value outlive that variable, caller would need to apply heap_copytuple...
* but current callers only need a short-lived tuple value anyway.
*
* Returns a pointer to the TupleDesc of the datum's rowtype.
* Caller is responsible for calling ReleaseTupleDesc when done with it.
*
* Note: it's caller's responsibility to be sure value is of composite type.
* Also, best to call this in a short-lived context, as it might leak memory.
*/
static TupleDesc
deconstruct_composite_datum(Datum value, HeapTupleData *tmptup)
{
HeapTupleHeader td;
Oid tupType;
int32 tupTypmod;
/* Get tuple body (note this could involve detoasting) */
td = DatumGetHeapTupleHeader(value);
/* Build a temporary HeapTuple control structure */
tmptup->t_len = HeapTupleHeaderGetDatumLength(td);
ItemPointerSetInvalid(&(tmptup->t_self));
tmptup->t_tableOid = InvalidOid;
tmptup->t_data = td;
/* Extract rowtype info and find a tupdesc */
tupType = HeapTupleHeaderGetTypeId(td);
tupTypmod = HeapTupleHeaderGetTypMod(td);
return lookup_rowtype_tupdesc(tupType, tupTypmod);
}
/*
* exec_move_row_from_datum Move a composite Datum into a record or row
*
* This is equivalent to deconstruct_composite_datum() followed by
* exec_move_row(), but we can optimize things if the Datum is an
* expanded-record reference.
*
* Note: it's caller's responsibility to be sure value is of composite type.
*/
static void
exec_move_row_from_datum(PLpgSQL_execstate *estate,
PLpgSQL_variable *target,
Datum value)
{
/* Check to see if source is an expanded record */
if (VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(value)))
{
ExpandedRecordHeader *erh = (ExpandedRecordHeader *) DatumGetEOHP(value);
ExpandedRecordHeader *newerh = NULL;
Assert(erh->er_magic == ER_MAGIC);
/* These cases apply if the target is record not row... */
if (target->dtype == PLPGSQL_DTYPE_REC)
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) target;
/*
* If it's the same record already stored in the variable, do
* nothing. This would happen only in silly cases like "r := r",
* but we need some check to avoid possibly freeing the variable's
* live value below. Note that this applies even if what we have
* is a R/O pointer.
*/
if (erh == rec->erh)
return;
/*
* If we have a R/W pointer, we're allowed to just commandeer
* ownership of the expanded record. If it's of the right type to
* put into the record variable, do that. (Note we don't accept
* an expanded record of a composite-domain type as a RECORD
* value. We'll treat it as the base composite type instead;
* compare logic in make_expanded_record_for_rec.)
*/
if (VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(value)) &&
(rec->rectypeid == erh->er_decltypeid ||
(rec->rectypeid == RECORDOID &&
!ExpandedRecordIsDomain(erh))))
{
assign_record_var(estate, rec, erh);
return;
}
/*
* If we already have an expanded record object in the target
* variable, and the source record contains a valid tuple
* representation with the right rowtype, then we can skip making
* a new expanded record and just assign the tuple with
* expanded_record_set_tuple. (We can't do the equivalent if we
* have to do field-by-field assignment, since that wouldn't be
* atomic if there's an error.) We consider that there's a
* rowtype match only if it's the same named composite type or
* same registered rowtype; checking for matches of anonymous
* rowtypes would be more expensive than this is worth.
*/
if (rec->erh &&
(erh->flags & ER_FLAG_FVALUE_VALID) &&
erh->er_typeid == rec->erh->er_typeid &&
(erh->er_typeid != RECORDOID ||
(erh->er_typmod == rec->erh->er_typmod &&
erh->er_typmod >= 0)))
{
expanded_record_set_tuple(rec->erh, erh->fvalue,
true, !estate->atomic);
return;
}
/*
* Otherwise we're gonna need a new expanded record object. Make
* it here in hopes of piggybacking on the source object's
* previous typcache lookup.
*/
newerh = make_expanded_record_for_rec(estate, rec, NULL, erh);
/*
* If the expanded record contains a valid tuple representation,
* and we don't need rowtype conversion, then just copying the
* tuple is probably faster than field-by-field processing. (This
* isn't duplicative of the previous check, since here we will
* catch the case where the record variable was previously empty.)
*/
if ((erh->flags & ER_FLAG_FVALUE_VALID) &&
(rec->rectypeid == RECORDOID ||
rec->rectypeid == erh->er_typeid))
{
expanded_record_set_tuple(newerh, erh->fvalue,
true, !estate->atomic);
assign_record_var(estate, rec, newerh);
return;
}
/*
* Need to special-case empty source record, else code below would
* leak newerh.
*/
if (ExpandedRecordIsEmpty(erh))
{
/* Set newerh to a row of NULLs */
deconstruct_expanded_record(newerh);
assign_record_var(estate, rec, newerh);
return;
}
} /* end of record-target-only cases */
/*
* If the source expanded record is empty, we should treat that like a
* NULL tuple value. (We're unlikely to see such a case, but we must
* check this; deconstruct_expanded_record would cause a change of
* logical state, which is not OK.)
*/
if (ExpandedRecordIsEmpty(erh))
{
exec_move_row(estate, target, NULL,
expanded_record_get_tupdesc(erh));
return;
}
/*
* Otherwise, ensure that the source record is deconstructed, and
* assign from its field values.
*/
deconstruct_expanded_record(erh);
exec_move_row_from_fields(estate, target, newerh,
erh->dvalues, erh->dnulls,
expanded_record_get_tupdesc(erh));
}
else
{
/*
* Nope, we've got a plain composite Datum. Deconstruct it; but we
* don't use deconstruct_composite_datum(), because we may be able to
* skip calling lookup_rowtype_tupdesc().
*/
HeapTupleHeader td;
HeapTupleData tmptup;
Oid tupType;
int32 tupTypmod;
TupleDesc tupdesc;
MemoryContext oldcontext;
/* Ensure that any detoasted data winds up in the eval_mcontext */
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
/* Get tuple body (note this could involve detoasting) */
td = DatumGetHeapTupleHeader(value);
MemoryContextSwitchTo(oldcontext);
/* Build a temporary HeapTuple control structure */
tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
ItemPointerSetInvalid(&(tmptup.t_self));
tmptup.t_tableOid = InvalidOid;
tmptup.t_data = td;
/* Extract rowtype info */
tupType = HeapTupleHeaderGetTypeId(td);
tupTypmod = HeapTupleHeaderGetTypMod(td);
/* Now, if the target is record not row, maybe we can optimize ... */
if (target->dtype == PLPGSQL_DTYPE_REC)
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) target;
/*
* If we already have an expanded record object in the target
* variable, and the source datum has a matching rowtype, then we
* can skip making a new expanded record and just assign the tuple
* with expanded_record_set_tuple. We consider that there's a
* rowtype match only if it's the same named composite type or
* same registered rowtype. (Checking to reject an anonymous
* rowtype here should be redundant, but let's be safe.)
*/
if (rec->erh &&
tupType == rec->erh->er_typeid &&
(tupType != RECORDOID ||
(tupTypmod == rec->erh->er_typmod &&
tupTypmod >= 0)))
{
expanded_record_set_tuple(rec->erh, &tmptup,
true, !estate->atomic);
return;
}
/*
* If the source datum has a rowtype compatible with the target
* variable, just build a new expanded record and assign the tuple
* into it. Using make_expanded_record_from_typeid() here saves
* one typcache lookup compared to the code below.
*/
if (rec->rectypeid == RECORDOID || rec->rectypeid == tupType)
{
ExpandedRecordHeader *newerh;
MemoryContext mcontext = get_eval_mcontext(estate);
newerh = make_expanded_record_from_typeid(tupType, tupTypmod,
mcontext);
expanded_record_set_tuple(newerh, &tmptup,
true, !estate->atomic);
assign_record_var(estate, rec, newerh);
return;
}
/*
* Otherwise, we're going to need conversion, so fall through to
* do it the hard way.
*/
}
/*
* ROW target, or unoptimizable RECORD target, so we have to expend a
* lookup to obtain the source datum's tupdesc.
*/
tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
/* Do the move */
exec_move_row(estate, target, &tmptup, tupdesc);
/* Release tupdesc usage count */
ReleaseTupleDesc(tupdesc);
}
}
/*
* If we have not created an expanded record to hold the record variable's
* value, do so. The expanded record will be "empty", so this does not
* change the logical state of the record variable: it's still NULL.
* However, now we'll have a tupdesc with which we can e.g. look up fields.
*/
static void
instantiate_empty_record_variable(PLpgSQL_execstate *estate, PLpgSQL_rec *rec)
{
Assert(rec->erh == NULL); /* else caller error */
/* If declared type is RECORD, we can't instantiate */
if (rec->rectypeid == RECORDOID)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("record \"%s\" is not assigned yet", rec->refname),
errdetail("The tuple structure of a not-yet-assigned record is indeterminate.")));
/* OK, do it */
rec->erh = make_expanded_record_from_typeid(rec->rectypeid, -1,
estate->datum_context);
}
/* ----------
* convert_value_to_string Convert a non-null Datum to C string
*
* Note: the result is in the estate's eval_mcontext, and will be cleared
* by the next exec_eval_cleanup() call. The invoked output function might
* leave additional cruft there as well, so just pfree'ing the result string
* would not be enough to avoid memory leaks if we did not do it like this.
* In most usages the Datum being passed in is also in that context (if
* pass-by-reference) and so an exec_eval_cleanup() call is needed anyway.
*
* Note: not caching the conversion function lookup is bad for performance.
* However, this function isn't currently used in any places where an extra
* catalog lookup or two seems like a big deal.
* ----------
*/
static char *
convert_value_to_string(PLpgSQL_execstate *estate, Datum value, Oid valtype)
{
char *result;
MemoryContext oldcontext;
Oid typoutput;
bool typIsVarlena;
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
getTypeOutputInfo(valtype, &typoutput, &typIsVarlena);
result = OidOutputFunctionCall(typoutput, value);
MemoryContextSwitchTo(oldcontext);
return result;
}
/* ----------
* exec_cast_value Cast a value if required
*
* Note that *isnull is an input and also an output parameter. While it's
* unlikely that a cast operation would produce null from non-null or vice
* versa, that could happen in principle.
*
* Note: the estate's eval_mcontext is used for temporary storage, and may
* also contain the result Datum if we have to do a conversion to a pass-
* by-reference data type. Be sure to do an exec_eval_cleanup() call when
* done with the result.
* ----------
*/
static Datum
exec_cast_value(PLpgSQL_execstate *estate,
Datum value, bool *isnull,
Oid valtype, int32 valtypmod,
Oid reqtype, int32 reqtypmod)
{
/*
* If the type of the given value isn't what's requested, convert it.
*/
if (valtype != reqtype ||
(valtypmod != reqtypmod && reqtypmod != -1))
{
plpgsql_CastHashEntry *cast_entry;
cast_entry = get_cast_hashentry(estate,
valtype, valtypmod,
reqtype, reqtypmod);
if (cast_entry)
{
ExprContext *econtext = estate->eval_econtext;
MemoryContext oldcontext;
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
econtext->caseValue_datum = value;
econtext->caseValue_isNull = *isnull;
cast_entry->cast_in_use = true;
value = ExecEvalExpr(cast_entry->cast_exprstate, econtext,
isnull);
cast_entry->cast_in_use = false;
MemoryContextSwitchTo(oldcontext);
}
}
return value;
}
/* ----------
* get_cast_hashentry Look up how to perform a type cast
*
* Returns a plpgsql_CastHashEntry if an expression has to be evaluated,
* or NULL if the cast is a mere no-op relabeling. If there's work to be
* done, the cast_exprstate field contains an expression evaluation tree
* based on a CaseTestExpr input, and the cast_in_use field should be set
* true while executing it.
* ----------
*/
static plpgsql_CastHashEntry *
get_cast_hashentry(PLpgSQL_execstate *estate,
Oid srctype, int32 srctypmod,
Oid dsttype, int32 dsttypmod)
{
plpgsql_CastHashKey cast_key;
plpgsql_CastHashEntry *cast_entry;
bool found;
LocalTransactionId curlxid;
MemoryContext oldcontext;
/* Look for existing entry */
cast_key.srctype = srctype;
cast_key.dsttype = dsttype;
cast_key.srctypmod = srctypmod;
cast_key.dsttypmod = dsttypmod;
cast_entry = (plpgsql_CastHashEntry *) hash_search(estate->cast_hash,
(void *) &cast_key,
HASH_ENTER, &found);
if (!found) /* initialize if new entry */
cast_entry->cast_cexpr = NULL;
if (cast_entry->cast_cexpr == NULL ||
!cast_entry->cast_cexpr->is_valid)
{
/*
* We've not looked up this coercion before, or we have but the cached
* expression has been invalidated.
*/
Node *cast_expr;
CachedExpression *cast_cexpr;
CaseTestExpr *placeholder;
/*
* Drop old cached expression if there is one.
*/
if (cast_entry->cast_cexpr)
{
FreeCachedExpression(cast_entry->cast_cexpr);
cast_entry->cast_cexpr = NULL;
}
/*
* Since we could easily fail (no such coercion), construct a
* temporary coercion expression tree in the short-lived
* eval_mcontext, then if successful save it as a CachedExpression.
*/
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
/*
* We use a CaseTestExpr as the base of the coercion tree, since it's
* very cheap to insert the source value for that.
*/
placeholder = makeNode(CaseTestExpr);
placeholder->typeId = srctype;
placeholder->typeMod = srctypmod;
placeholder->collation = get_typcollation(srctype);
/*
* Apply coercion. We use ASSIGNMENT coercion because that's the
* closest match to plpgsql's historical behavior; in particular,
* EXPLICIT coercion would allow silent truncation to a destination
* varchar/bpchar's length, which we do not want.
*
* If source type is UNKNOWN, coerce_to_target_type will fail (it only
* expects to see that for Const input nodes), so don't call it; we'll
* apply CoerceViaIO instead. Likewise, it doesn't currently work for
* coercing RECORD to some other type, so skip for that too.
*/
if (srctype == UNKNOWNOID || srctype == RECORDOID)
cast_expr = NULL;
else
cast_expr = coerce_to_target_type(NULL,
(Node *) placeholder, srctype,
dsttype, dsttypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
/*
* If there's no cast path according to the parser, fall back to using
* an I/O coercion; this is semantically dubious but matches plpgsql's
* historical behavior. We would need something of the sort for
* UNKNOWN literals in any case.
*/
if (cast_expr == NULL)
{
CoerceViaIO *iocoerce = makeNode(CoerceViaIO);
iocoerce->arg = (Expr *) placeholder;
iocoerce->resulttype = dsttype;
iocoerce->resultcollid = InvalidOid;
iocoerce->coerceformat = COERCE_IMPLICIT_CAST;
iocoerce->location = -1;
cast_expr = (Node *) iocoerce;
if (dsttypmod != -1)
cast_expr = coerce_to_target_type(NULL,
cast_expr, dsttype,
dsttype, dsttypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
}
/* Note: we don't bother labeling the expression tree with collation */
/* Plan the expression and build a CachedExpression */
cast_cexpr = GetCachedExpression(cast_expr);
cast_expr = cast_cexpr->expr;
/* Detect whether we have a no-op (RelabelType) coercion */
if (IsA(cast_expr, RelabelType) &&
((RelabelType *) cast_expr)->arg == (Expr *) placeholder)
cast_expr = NULL;
/* Now we can fill in the hashtable entry. */
cast_entry->cast_cexpr = cast_cexpr;
cast_entry->cast_expr = (Expr *) cast_expr;
cast_entry->cast_exprstate = NULL;
cast_entry->cast_in_use = false;
cast_entry->cast_lxid = InvalidLocalTransactionId;
MemoryContextSwitchTo(oldcontext);
}
/* Done if we have determined that this is a no-op cast. */
if (cast_entry->cast_expr == NULL)
return NULL;
/*
* Prepare the expression for execution, if it's not been done already in
* the current transaction; also, if it's marked busy in the current
* transaction, abandon that expression tree and build a new one, so as to
* avoid potential problems with recursive cast expressions and failed
* executions. (We will leak some memory intra-transaction if that
* happens a lot, but we don't expect it to.) It's okay to update the
* hash table with the new tree because all plpgsql functions within a
* given transaction share the same simple_eval_estate. (Well, regular
* functions do; DO blocks have private simple_eval_estates, and private
* cast hash tables to go with them.)
*/
curlxid = MyProc->lxid;
if (cast_entry->cast_lxid != curlxid || cast_entry->cast_in_use)
{
oldcontext = MemoryContextSwitchTo(estate->simple_eval_estate->es_query_cxt);
cast_entry->cast_exprstate = ExecInitExpr(cast_entry->cast_expr, NULL);
cast_entry->cast_in_use = false;
cast_entry->cast_lxid = curlxid;
MemoryContextSwitchTo(oldcontext);
}
return cast_entry;
}
/* ----------
* exec_simple_check_plan - Check if a plan is simple enough to
* be evaluated by ExecEvalExpr() instead
* of SPI.
* ----------
*/
static void
exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr)
{
List *plansources;
CachedPlanSource *plansource;
Query *query;
CachedPlan *cplan;
MemoryContext oldcontext;
/*
* Initialize to "not simple".
*/
expr->expr_simple_expr = NULL;
/*
* Check the analyzed-and-rewritten form of the query to see if we will be
* able to treat it as a simple expression. Since this function is only
* called immediately after creating the CachedPlanSource, we need not
* worry about the query being stale.
*/
/*
* We can only test queries that resulted in exactly one CachedPlanSource
*/
plansources = SPI_plan_get_plan_sources(expr->plan);
if (list_length(plansources) != 1)
return;
plansource = (CachedPlanSource *) linitial(plansources);
/*
* 1. There must be one single querytree.
*/
if (list_length(plansource->query_list) != 1)
return;
query = (Query *) linitial(plansource->query_list);
/*
* 2. It must be a plain SELECT query without any input tables
*/
if (!IsA(query, Query))
return;
if (query->commandType != CMD_SELECT)
return;
if (query->rtable != NIL)
return;
/*
* 3. Can't have any subplans, aggregates, qual clauses either. (These
* tests should generally match what inline_function() checks before
* inlining a SQL function; otherwise, inlining could change our
* conclusion about whether an expression is simple, which we don't want.)
*/
if (query->hasAggs ||
query->hasWindowFuncs ||
query->hasTargetSRFs ||
query->hasSubLinks ||
query->cteList ||
query->jointree->fromlist ||
query->jointree->quals ||
query->groupClause ||
query->groupingSets ||
query->havingQual ||
query->windowClause ||
query->distinctClause ||
query->sortClause ||
query->limitOffset ||
query->limitCount ||
query->setOperations)
return;
/*
* 4. The query must have a single attribute as result
*/
if (list_length(query->targetList) != 1)
return;
/*
* OK, we can treat it as a simple plan.
*
* Get the generic plan for the query. If replanning is needed, do that
* work in the eval_mcontext.
*/
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
cplan = SPI_plan_get_cached_plan(expr->plan);
MemoryContextSwitchTo(oldcontext);
/* Can't fail, because we checked for a single CachedPlanSource above */
Assert(cplan != NULL);
/* Share the remaining work with replan code path */
exec_save_simple_expr(expr, cplan);
/* Release our plan refcount */
ReleaseCachedPlan(cplan, true);
}
/*
* exec_save_simple_expr --- extract simple expression from CachedPlan
*/
static void
exec_save_simple_expr(PLpgSQL_expr *expr, CachedPlan *cplan)
{
PlannedStmt *stmt;
Plan *plan;
Expr *tle_expr;
/*
* Given the checks that exec_simple_check_plan did, none of the Asserts
* here should ever fail.
*/
/* Extract the single PlannedStmt */
Assert(list_length(cplan->stmt_list) == 1);
stmt = linitial_node(PlannedStmt, cplan->stmt_list);
Assert(stmt->commandType == CMD_SELECT);
/*
* Ordinarily, the plan node should be a simple Result. However, if
* force_parallel_mode is on, the planner might've stuck a Gather node
* atop that. The simplest way to deal with this is to look through the
* Gather node. The Gather node's tlist would normally contain a Var
* referencing the child node's output, but it could also be a Param, or
* it could be a Const that setrefs.c copied as-is.
*/
plan = stmt->planTree;
for (;;)
{
/* Extract the single tlist expression */
Assert(list_length(plan->targetlist) == 1);
tle_expr = castNode(TargetEntry, linitial(plan->targetlist))->expr;
if (IsA(plan, Result))
{
Assert(plan->lefttree == NULL &&
plan->righttree == NULL &&
plan->initPlan == NULL &&
plan->qual == NULL &&
((Result *) plan)->resconstantqual == NULL);
break;
}
else if (IsA(plan, Gather))
{
Assert(plan->lefttree != NULL &&
plan->righttree == NULL &&
plan->initPlan == NULL &&
plan->qual == NULL);
/* If setrefs.c copied up a Const, no need to look further */
if (IsA(tle_expr, Const))
break;
/* Otherwise, it had better be a Param or an outer Var */
Assert(IsA(tle_expr, Param) ||(IsA(tle_expr, Var) &&
((Var *) tle_expr)->varno == OUTER_VAR));
/* Descend to the child node */
plan = plan->lefttree;
}
else
elog(ERROR, "unexpected plan node type: %d",
(int) nodeTag(plan));
}
/*
* Save the simple expression, and initialize state to "not valid in
* current transaction".
*/
expr->expr_simple_expr = tle_expr;
expr->expr_simple_generation = cplan->generation;
expr->expr_simple_state = NULL;
expr->expr_simple_in_use = false;
expr->expr_simple_lxid = InvalidLocalTransactionId;
/* Also stash away the expression result type */
expr->expr_simple_type = exprType((Node *) tle_expr);
expr->expr_simple_typmod = exprTypmod((Node *) tle_expr);
}
/*
* exec_check_rw_parameter --- can we pass expanded object as read/write param?
*
* If we have an assignment like "x := array_append(x, foo)" in which the
* top-level function is trusted not to corrupt its argument in case of an
* error, then when x has an expanded object as value, it is safe to pass the
* value as a read/write pointer and let the function modify the value
* in-place.
*
* This function checks for a safe expression, and sets expr->rwparam to the
* dno of the target variable (x) if safe, or -1 if not safe.
*/
static void
exec_check_rw_parameter(PLpgSQL_expr *expr, int target_dno)
{
Oid funcid;
List *fargs;
ListCell *lc;
/* Assume unsafe */
expr->rwparam = -1;
/*
* If the expression isn't simple, there's no point in trying to optimize
* (because the exec_run_select code path will flatten any expanded result
* anyway). Even without that, this seems like a good safety restriction.
*/
if (expr->expr_simple_expr == NULL)
return;
/*
* If target variable isn't referenced by expression, no need to look
* further.
*/
if (!bms_is_member(target_dno, expr->paramnos))
return;
/*
* Top level of expression must be a simple FuncExpr or OpExpr.
*/
if (IsA(expr->expr_simple_expr, FuncExpr))
{
FuncExpr *fexpr = (FuncExpr *) expr->expr_simple_expr;
funcid = fexpr->funcid;
fargs = fexpr->args;
}
else if (IsA(expr->expr_simple_expr, OpExpr))
{
OpExpr *opexpr = (OpExpr *) expr->expr_simple_expr;
funcid = opexpr->opfuncid;
fargs = opexpr->args;
}
else
return;
/*
* The top-level function must be one that we trust to be "safe".
* Currently we hard-wire the list, but it would be very desirable to
* allow extensions to mark their functions as safe ...
*/
if (!(funcid == F_ARRAY_APPEND ||
funcid == F_ARRAY_PREPEND))
return;
/*
* The target variable (in the form of a Param) must only appear as a
* direct argument of the top-level function.
*/
foreach(lc, fargs)
{
Node *arg = (Node *) lfirst(lc);
/* A Param is OK, whether it's the target variable or not */
if (arg && IsA(arg, Param))
continue;
/* Otherwise, argument expression must not reference target */
if (contains_target_param(arg, &target_dno))
return;
}
/* OK, we can pass target as a read-write parameter */
expr->rwparam = target_dno;
}
/*
* Recursively check for a Param referencing the target variable
*/
static bool
contains_target_param(Node *node, int *target_dno)
{
if (node == NULL)
return false;
if (IsA(node, Param))
{
Param *param = (Param *) node;
if (param->paramkind == PARAM_EXTERN &&
param->paramid == *target_dno + 1)
return true;
return false;
}
return expression_tree_walker(node, contains_target_param,
(void *) target_dno);
}
/* ----------
* exec_set_found Set the global found variable to true/false
* ----------
*/
static void
exec_set_found(PLpgSQL_execstate *estate, bool state)
{
PLpgSQL_var *var;
var = (PLpgSQL_var *) (estate->datums[estate->found_varno]);
assign_simple_var(estate, var, BoolGetDatum(state), false, false);
}
/*
* plpgsql_create_econtext --- create an eval_econtext for the current function
*
* We may need to create a new shared_simple_eval_estate too, if there's not
* one already for the current transaction. The EState will be cleaned up at
* transaction end.
*/
static void
plpgsql_create_econtext(PLpgSQL_execstate *estate)
{
SimpleEcontextStackEntry *entry;
/*
* Create an EState for evaluation of simple expressions, if there's not
* one already in the current transaction. The EState is made a child of
* TopTransactionContext so it will have the right lifespan.
*
* Note that this path is never taken when executing a DO block; the
* required EState was already made by plpgsql_inline_handler.
*/
if (estate->simple_eval_estate == NULL)
{
MemoryContext oldcontext;
if (shared_simple_eval_estate == NULL)
{
oldcontext = MemoryContextSwitchTo(TopTransactionContext);
shared_simple_eval_estate = CreateExecutorState();
MemoryContextSwitchTo(oldcontext);
}
estate->simple_eval_estate = shared_simple_eval_estate;
}
/*
* Create a child econtext for the current function.
*/
estate->eval_econtext = CreateExprContext(estate->simple_eval_estate);
/*
* Make a stack entry so we can clean up the econtext at subxact end.
* Stack entries are kept in TopTransactionContext for simplicity.
*/
entry = (SimpleEcontextStackEntry *)
MemoryContextAlloc(TopTransactionContext,
sizeof(SimpleEcontextStackEntry));
entry->stack_econtext = estate->eval_econtext;
entry->xact_subxid = GetCurrentSubTransactionId();
entry->next = simple_econtext_stack;
simple_econtext_stack = entry;
}
/*
* plpgsql_destroy_econtext --- destroy function's econtext
*
* We check that it matches the top stack entry, and destroy the stack
* entry along with the context.
*/
static void
plpgsql_destroy_econtext(PLpgSQL_execstate *estate)
{
SimpleEcontextStackEntry *next;
Assert(simple_econtext_stack != NULL);
Assert(simple_econtext_stack->stack_econtext == estate->eval_econtext);
next = simple_econtext_stack->next;
pfree(simple_econtext_stack);
simple_econtext_stack = next;
FreeExprContext(estate->eval_econtext, true);
estate->eval_econtext = NULL;
}
/*
* plpgsql_xact_cb --- post-transaction-commit-or-abort cleanup
*
* If a simple-expression EState was created in the current transaction,
* it has to be cleaned up.
*/
void
plpgsql_xact_cb(XactEvent event, void *arg)
{
/*
* If we are doing a clean transaction shutdown, free the EState (so that
* any remaining resources will be released correctly). In an abort, we
* expect the regular abort recovery procedures to release everything of
* interest.
*/
if (event == XACT_EVENT_COMMIT || event == XACT_EVENT_PREPARE)
{
simple_econtext_stack = NULL;
if (shared_simple_eval_estate)
FreeExecutorState(shared_simple_eval_estate);
shared_simple_eval_estate = NULL;
}
else if (event == XACT_EVENT_ABORT)
{
simple_econtext_stack = NULL;
shared_simple_eval_estate = NULL;
}
}
/*
* plpgsql_subxact_cb --- post-subtransaction-commit-or-abort cleanup
*
* Make sure any simple-expression econtexts created in the current
* subtransaction get cleaned up. We have to do this explicitly because
* no other code knows which econtexts belong to which level of subxact.
*/
void
plpgsql_subxact_cb(SubXactEvent event, SubTransactionId mySubid,
SubTransactionId parentSubid, void *arg)
{
if (event == SUBXACT_EVENT_COMMIT_SUB || event == SUBXACT_EVENT_ABORT_SUB)
{
while (simple_econtext_stack != NULL &&
simple_econtext_stack->xact_subxid == mySubid)
{
SimpleEcontextStackEntry *next;
FreeExprContext(simple_econtext_stack->stack_econtext,
(event == SUBXACT_EVENT_COMMIT_SUB));
next = simple_econtext_stack->next;
pfree(simple_econtext_stack);
simple_econtext_stack = next;
}
}
}
/*
* assign_simple_var --- assign a new value to any VAR datum.
*
* This should be the only mechanism for assignment to simple variables,
* lest we do the release of the old value incorrectly (not to mention
* the detoasting business).
*/
static void
assign_simple_var(PLpgSQL_execstate *estate, PLpgSQL_var *var,
Datum newvalue, bool isnull, bool freeable)
{
Assert(var->dtype == PLPGSQL_DTYPE_VAR ||
var->dtype == PLPGSQL_DTYPE_PROMISE);
/*
* In non-atomic contexts, we do not want to store TOAST pointers in
* variables, because such pointers might become stale after a commit.
* Forcibly detoast in such cases. We don't want to detoast (flatten)
* expanded objects, however; those should be OK across a transaction
* boundary since they're just memory-resident objects. (Elsewhere in
* this module, operations on expanded records likewise need to request
* detoasting of record fields when !estate->atomic. Expanded arrays are
* not a problem since all array entries are always detoasted.)
*/
if (!estate->atomic && !isnull && var->datatype->typlen == -1 &&
VARATT_IS_EXTERNAL_NON_EXPANDED(DatumGetPointer(newvalue)))
{
MemoryContext oldcxt;
Datum detoasted;
/*
* Do the detoasting in the eval_mcontext to avoid long-term leakage
* of whatever memory toast fetching might leak. Then we have to copy
* the detoasted datum to the function's main context, which is a
* pain, but there's little choice.
*/
oldcxt = MemoryContextSwitchTo(get_eval_mcontext(estate));
detoasted = PointerGetDatum(heap_tuple_fetch_attr((struct varlena *) DatumGetPointer(newvalue)));
MemoryContextSwitchTo(oldcxt);
/* Now's a good time to not leak the input value if it's freeable */
if (freeable)
pfree(DatumGetPointer(newvalue));
/* Once we copy the value, it's definitely freeable */
newvalue = datumCopy(detoasted, false, -1);
freeable = true;
/* Can't clean up eval_mcontext here, but it'll happen before long */
}
/* Free the old value if needed */
if (var->freeval)
{
if (DatumIsReadWriteExpandedObject(var->value,
var->isnull,
var->datatype->typlen))
DeleteExpandedObject(var->value);
else
pfree(DatumGetPointer(var->value));
}
/* Assign new value to datum */
var->value = newvalue;
var->isnull = isnull;
var->freeval = freeable;
/*
* If it's a promise variable, then either we just assigned the promised
* value, or the user explicitly assigned an overriding value. Either
* way, cancel the promise.
*/
var->promise = PLPGSQL_PROMISE_NONE;
}
/*
* free old value of a text variable and assign new value from C string
*/
static void
assign_text_var(PLpgSQL_execstate *estate, PLpgSQL_var *var, const char *str)
{
assign_simple_var(estate, var, CStringGetTextDatum(str), false, true);
}
/*
* assign_record_var --- assign a new value to any REC datum.
*/
static void
assign_record_var(PLpgSQL_execstate *estate, PLpgSQL_rec *rec,
ExpandedRecordHeader *erh)
{
Assert(rec->dtype == PLPGSQL_DTYPE_REC);
/* Transfer new record object into datum_context */
TransferExpandedRecord(erh, estate->datum_context);
/* Free the old value ... */
if (rec->erh)
DeleteExpandedObject(ExpandedRecordGetDatum(rec->erh));
/* ... and install the new */
rec->erh = erh;
}
/*
* exec_eval_using_params --- evaluate params of USING clause
*
* The result data structure is created in the stmt_mcontext, and should
* be freed by resetting that context.
*/
static PreparedParamsData *
exec_eval_using_params(PLpgSQL_execstate *estate, List *params)
{
PreparedParamsData *ppd;
MemoryContext stmt_mcontext = get_stmt_mcontext(estate);
int nargs;
int i;
ListCell *lc;
ppd = (PreparedParamsData *)
MemoryContextAlloc(stmt_mcontext, sizeof(PreparedParamsData));
nargs = list_length(params);
ppd->nargs = nargs;
ppd->types = (Oid *)
MemoryContextAlloc(stmt_mcontext, nargs * sizeof(Oid));
ppd->values = (Datum *)
MemoryContextAlloc(stmt_mcontext, nargs * sizeof(Datum));
ppd->nulls = (char *)
MemoryContextAlloc(stmt_mcontext, nargs * sizeof(char));
i = 0;
foreach(lc, params)
{
PLpgSQL_expr *param = (PLpgSQL_expr *) lfirst(lc);
bool isnull;
int32 ppdtypmod;
MemoryContext oldcontext;
ppd->values[i] = exec_eval_expr(estate, param,
&isnull,
&ppd->types[i],
&ppdtypmod);
ppd->nulls[i] = isnull ? 'n' : ' ';
oldcontext = MemoryContextSwitchTo(stmt_mcontext);
if (ppd->types[i] == UNKNOWNOID)
{
/*
* Treat 'unknown' parameters as text, since that's what most
* people would expect. SPI_execute_with_args can coerce unknown
* constants in a more intelligent way, but not unknown Params.
* This code also takes care of copying into the right context.
* Note we assume 'unknown' has the representation of C-string.
*/
ppd->types[i] = TEXTOID;
if (!isnull)
ppd->values[i] = CStringGetTextDatum(DatumGetCString(ppd->values[i]));
}
/* pass-by-ref non null values must be copied into stmt_mcontext */
else if (!isnull)
{
int16 typLen;
bool typByVal;
get_typlenbyval(ppd->types[i], &typLen, &typByVal);
if (!typByVal)
ppd->values[i] = datumCopy(ppd->values[i], typByVal, typLen);
}
MemoryContextSwitchTo(oldcontext);
exec_eval_cleanup(estate);
i++;
}
return ppd;
}
/*
* Open portal for dynamic query
*
* Caution: this resets the stmt_mcontext at exit. We might eventually need
* to move that responsibility to the callers, but currently no caller needs
* to have statement-lifetime temp data that survives past this, so it's
* simpler to do it here.
*/
static Portal
exec_dynquery_with_params(PLpgSQL_execstate *estate,
PLpgSQL_expr *dynquery,
List *params,
const char *portalname,
int cursorOptions)
{
Portal portal;
Datum query;
bool isnull;
Oid restype;
int32 restypmod;
char *querystr;
MemoryContext stmt_mcontext = get_stmt_mcontext(estate);
/*
* Evaluate the string expression after the EXECUTE keyword. Its result is
* the querystring we have to execute.
*/
query = exec_eval_expr(estate, dynquery, &isnull, &restype, &restypmod);
if (isnull)
ereport(ERROR,
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("query string argument of EXECUTE is null")));
/* Get the C-String representation */
querystr = convert_value_to_string(estate, query, restype);
/* copy it into the stmt_mcontext before we clean up */
querystr = MemoryContextStrdup(stmt_mcontext, querystr);
exec_eval_cleanup(estate);
/*
* Open an implicit cursor for the query. We use
* SPI_cursor_open_with_args even when there are no params, because this
* avoids making and freeing one copy of the plan.
*/
if (params)
{
PreparedParamsData *ppd;
ppd = exec_eval_using_params(estate, params);
portal = SPI_cursor_open_with_args(portalname,
querystr,
ppd->nargs, ppd->types,
ppd->values, ppd->nulls,
estate->readonly_func,
cursorOptions);
}
else
{
portal = SPI_cursor_open_with_args(portalname,
querystr,
0, NULL,
NULL, NULL,
estate->readonly_func,
cursorOptions);
}
if (portal == NULL)
elog(ERROR, "could not open implicit cursor for query \"%s\": %s",
querystr, SPI_result_code_string(SPI_result));
/* Release transient data */
MemoryContextReset(stmt_mcontext);
return portal;
}
/*
* Return a formatted string with information about an expression's parameters,
* or NULL if the expression does not take any parameters.
* The result is in the eval_mcontext.
*/
static char *
format_expr_params(PLpgSQL_execstate *estate,
const PLpgSQL_expr *expr)
{
int paramno;
int dno;
StringInfoData paramstr;
MemoryContext oldcontext;
if (!expr->paramnos)
return NULL;
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
initStringInfo(¶mstr);
paramno = 0;
dno = -1;
while ((dno = bms_next_member(expr->paramnos, dno)) >= 0)
{
Datum paramdatum;
Oid paramtypeid;
bool paramisnull;
int32 paramtypmod;
PLpgSQL_var *curvar;
curvar = (PLpgSQL_var *) estate->datums[dno];
exec_eval_datum(estate, (PLpgSQL_datum *) curvar,
¶mtypeid, ¶mtypmod,
¶mdatum, ¶misnull);
appendStringInfo(¶mstr, "%s%s = ",
paramno > 0 ? ", " : "",
curvar->refname);
if (paramisnull)
appendStringInfoString(¶mstr, "NULL");
else
{
char *value = convert_value_to_string(estate, paramdatum, paramtypeid);
char *p;
appendStringInfoCharMacro(¶mstr, '\'');
for (p = value; *p; p++)
{
if (*p == '\'') /* double single quotes */
appendStringInfoCharMacro(¶mstr, *p);
appendStringInfoCharMacro(¶mstr, *p);
}
appendStringInfoCharMacro(¶mstr, '\'');
}
paramno++;
}
MemoryContextSwitchTo(oldcontext);
return paramstr.data;
}
/*
* Return a formatted string with information about PreparedParamsData, or NULL
* if there are no parameters.
* The result is in the eval_mcontext.
*/
static char *
format_preparedparamsdata(PLpgSQL_execstate *estate,
const PreparedParamsData *ppd)
{
int paramno;
StringInfoData paramstr;
MemoryContext oldcontext;
if (!ppd)
return NULL;
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
initStringInfo(¶mstr);
for (paramno = 0; paramno < ppd->nargs; paramno++)
{
appendStringInfo(¶mstr, "%s$%d = ",
paramno > 0 ? ", " : "",
paramno + 1);
if (ppd->nulls[paramno] == 'n')
appendStringInfoString(¶mstr, "NULL");
else
{
char *value = convert_value_to_string(estate, ppd->values[paramno], ppd->types[paramno]);
char *p;
appendStringInfoCharMacro(¶mstr, '\'');
for (p = value; *p; p++)
{
if (*p == '\'') /* double single quotes */
appendStringInfoCharMacro(¶mstr, *p);
appendStringInfoCharMacro(¶mstr, *p);
}
appendStringInfoCharMacro(¶mstr, '\'');
}
}
MemoryContextSwitchTo(oldcontext);
return paramstr.data;
}
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