greenplumn subselect 源码
greenplumn subselect 代码
文件路径：/src/backend/optimizer/plan/subselect.c
/*-------------------------------------------------------------------------
*
* subselect.c
* Planning routines for subselects.
*
* This module deals with SubLinks and CTEs, but not subquery RTEs (i.e.,
* not sub-SELECT-in-FROM cases).
*
* Portions Copyright (c) 2005-2008, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/optimizer/plan/subselect.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/catalog.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_type.h"
#include "catalog/gp_distribution_policy.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/optimizer.h"
#include "optimizer/paramassign.h"
#include "optimizer/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/subselect.h"
#include "parser/parse_relation.h"
#include "parser/parsetree.h"
#include "parser/parse_oper.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "cdb/cdbllize.h"
#include "cdb/cdbmutate.h"
#include "cdb/cdbpathtoplan.h"
#include "cdb/cdbsubselect.h"
#include "cdb/cdbvars.h"
#include "cdb/cdbutil.h"
typedef struct convert_testexpr_context
{
PlannerInfo *root;
List *subst_nodes; /* Nodes to substitute for Params */
} convert_testexpr_context;
typedef struct process_sublinks_context
{
PlannerInfo *root;
bool isTopQual;
} process_sublinks_context;
typedef struct finalize_primnode_context
{
PlannerInfo *root;
Bitmapset *paramids; /* Non-local PARAM_EXEC paramids found */
} finalize_primnode_context;
typedef struct inline_cte_walker_context
{
const char *ctename; /* name and relative level of target CTE */
int levelsup;
int refcount; /* number of remaining references */
Query *ctequery; /* query to substitute */
} inline_cte_walker_context;
static Node *build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
List *plan_params,
SubLinkType subLinkType, int subLinkId,
Node *testexpr, bool adjust_testexpr,
bool unknownEqFalse);
static List *generate_subquery_params(PlannerInfo *root, List *tlist,
List **paramIds);
static Node *convert_testexpr_mutator(Node *node,
convert_testexpr_context *context);
static bool subplan_is_hashable(PlannerInfo *root, Plan *plan);
static bool testexpr_is_hashable(Node *testexpr);
static bool hash_ok_operator(OpExpr *expr);
#if 0
/*
* The following several functions are used by SS_process_ctes.
* But SS_process_ctes is commentted of because gpdb does not
* use it.
*/
static bool contain_dml(Node *node);
static bool contain_dml_walker(Node *node, void *context);
static bool contain_outer_selfref(Node *node);
static bool contain_outer_selfref_walker(Node *node, Index *depth);
static void inline_cte(PlannerInfo *root, CommonTableExpr *cte);
static bool inline_cte_walker(Node *node, inline_cte_walker_context *context);
#endif
static bool simplify_EXISTS_query(PlannerInfo *root, Query *query);
static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
Node **testexpr, List **paramIds);
static Node *replace_correlation_vars_mutator(Node *node, PlannerInfo *root);
static Node *process_sublinks_mutator(Node *node,
process_sublinks_context *context);
static Bitmapset *finalize_plan(PlannerInfo *root,
Plan *plan,
int gather_param,
Bitmapset *valid_params,
Bitmapset *scan_params);
static bool finalize_primnode(Node *node, finalize_primnode_context *context);
static bool finalize_agg_primnode(Node *node, finalize_primnode_context *context);
extern double global_work_mem(PlannerInfo *root);
/*
* Get the datatype/typmod/collation of the first column of the plan's output.
*
* This information is stored for ARRAY_SUBLINK execution and for
* exprType()/exprTypmod()/exprCollation(), which have no way to get at the
* plan associated with a SubPlan node. We really only need the info for
* EXPR_SUBLINK and ARRAY_SUBLINK subplans, but for consistency we save it
* always.
*/
static void
get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod,
Oid *colcollation)
{
/* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
if (plan->targetlist)
{
TargetEntry *tent = linitial_node(TargetEntry, plan->targetlist);
if (!tent->resjunk)
{
*coltype = exprType((Node *) tent->expr);
*coltypmod = exprTypmod((Node *) tent->expr);
*colcollation = exprCollation((Node *) tent->expr);
return;
}
}
*coltype = VOIDOID;
*coltypmod = -1;
*colcollation = InvalidOid;
}
/**
* Returns true if query refers to a distributed table.
*/
bool QueryHasDistributedRelation(Query *q, bool recursive)
{
ListCell *rt = NULL;
foreach(rt, q->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
if (rte->rtekind == RTE_SUBQUERY
&& recursive
&& QueryHasDistributedRelation(rte->subquery, true))
return true;
if (rte->relid != InvalidOid
&& rte->rtekind == RTE_RELATION)
{
GpPolicy *policy = GpPolicyFetch(rte->relid);
if (GpPolicyIsPartitioned(policy))
{
pfree(policy);
return true;
}
pfree(policy);
}
}
return false;
}
typedef struct CorrelatedVarWalkerContext
{
int maxLevelsUp;
} CorrelatedVarWalkerContext;
/**
* Walker finds the deepest correlation nesting i.e. maximum levelsup among all
* vars in subquery.
*/
static bool
CorrelatedVarWalker(Node *node, CorrelatedVarWalkerContext *ctx)
{
Assert(ctx);
if (node == NULL)
{
return false;
}
else if (IsA(node, Var))
{
Var * v = (Var *) node;
if (v->varlevelsup > ctx->maxLevelsUp)
{
ctx->maxLevelsUp = v->varlevelsup;
}
return false;
}
else if (IsA(node, Query))
{
return query_tree_walker((Query *) node, CorrelatedVarWalker, ctx, 0 /* flags */);
}
return expression_tree_walker(node, CorrelatedVarWalker, ctx);
}
/**
* Returns true if subquery is correlated
*/
bool
IsSubqueryCorrelated(Query *sq)
{
Assert(sq);
CorrelatedVarWalkerContext ctx;
ctx.maxLevelsUp = 0;
CorrelatedVarWalker((Node *) sq, &ctx);
return (ctx.maxLevelsUp > 0);
}
/**
* Returns true if subquery contains references to more than its immediate outer query.
*/
bool
IsSubqueryMultiLevelCorrelated(Query *sq)
{
Assert(sq);
CorrelatedVarWalkerContext ctx;
ctx.maxLevelsUp = 0;
CorrelatedVarWalker((Node *) sq, &ctx);
return (ctx.maxLevelsUp > 1);
}
/*
* Convert a SubLink (as created by the parser) into a SubPlan.
*
* We are given the SubLink's contained query, type, ID, and testexpr. We are
* also told if this expression appears at top level of a WHERE/HAVING qual.
*
* Note: we assume that the testexpr has been AND/OR flattened (actually,
* it's been through eval_const_expressions), but not converted to
* implicit-AND form; and any SubLinks in it should already have been
* converted to SubPlans. The subquery is as yet untouched, however.
*
* The result is whatever we need to substitute in place of the SubLink node
* in the executable expression. If we're going to do the subplan as a
* regular subplan, this will be the constructed SubPlan node. If we're going
* to do the subplan as an InitPlan, the SubPlan node instead goes into
* root->init_plans, and what we return here is an expression tree
* representing the InitPlan's result: usually just a Param node representing
* a single scalar result, but possibly a row comparison tree containing
* multiple Param nodes, or for a MULTIEXPR subquery a simple NULL constant
* (since the real output Params are elsewhere in the tree, and the MULTIEXPR
* subquery itself is in a resjunk tlist entry whose value is uninteresting).
*/
static Node *
make_subplan(PlannerInfo *root, Query *orig_subquery,
SubLinkType subLinkType, int subLinkId,
Node *testexpr, bool isTopQual)
{
Query *subquery;
bool simple_exists = false;
double tuple_fraction = 1.0;
PlannerInfo *subroot;
RelOptInfo *final_rel;
Path *best_path;
Plan *plan;
List *plan_params;
Node *result;
/*
* Copy the source Query node. This is a quick and dirty kluge to resolve
* the fact that the parser can generate trees with multiple links to the
* same sub-Query node, but the planner wants to scribble on the Query.
* Try to clean this up when we do querytree redesign...
*/
subquery = copyObject(orig_subquery);
/*
* If it's an EXISTS subplan, we might be able to simplify it.
*/
if (subLinkType == EXISTS_SUBLINK)
simple_exists = simplify_EXISTS_query(root, subquery);
/*
* For an EXISTS subplan, tell lower-level planner to expect that only the
* first tuple will be retrieved. For ALL and ANY subplans, we will be
* able to stop evaluating if the test condition fails or matches, so very
* often not all the tuples will be retrieved; for lack of a better idea,
* specify 50% retrieval. For EXPR, MULTIEXPR, and ROWCOMPARE subplans,
* use default behavior (we're only expecting one row out, anyway).
*
* NOTE: if you change these numbers, also change cost_subplan() in
* path/costsize.c.
*
* XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
* its output. In that case it would've been better to specify full
* retrieval. At present, however, we can only check hashability after
* we've made the subplan :-(. (Determining whether it'll fit in work_mem
* is the really hard part.) Therefore, we don't want to be too
* optimistic about the percentage of tuples retrieved, for fear of
* selecting a plan that's bad for the materialization case.
*/
if (subLinkType == EXISTS_SUBLINK)
tuple_fraction = 1.0; /* just like a LIMIT 1 */
else if (subLinkType == ALL_SUBLINK ||
subLinkType == ANY_SUBLINK)
tuple_fraction = 0.5; /* 50% */
else
tuple_fraction = 0.0; /* default behavior */
/* plan_params should not be in use in current query level */
Assert(root->plan_params == NIL);
PlannerConfig *config = CopyPlannerConfig(root->config);
if ((Gp_role == GP_ROLE_DISPATCH)
&& IsSubqueryMultiLevelCorrelated(subquery)
&& QueryHasDistributedRelation(subquery, root->is_correlated_subplan))
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("correlated subquery with skip-level correlations is not supported")));
}
if (Gp_role == GP_ROLE_DISPATCH)
config->is_under_subplan = true;
if (Gp_role == GP_ROLE_DISPATCH)
{
config->gp_cte_sharing = IsSubqueryCorrelated(subquery) ||
!(subLinkType == ROWCOMPARE_SUBLINK ||
subLinkType == ARRAY_SUBLINK ||
subLinkType == EXPR_SUBLINK ||
subLinkType == EXISTS_SUBLINK);
}
/*
* Strictly speaking, the order of rows in a subquery doesn't matter.
* Consider e.g. "WHERE IN (SELECT ...)". But in case of
* "ARRAY(SELECT foo ORDER BY bar)", we'd like to honor the ORDER BY,
* and construct the array in that order.
*/
if (subLinkType == ARRAY_SUBLINK)
config->honor_order_by = true;
else
config->honor_order_by = false;
/*
* Greenplum specific behavior:
* config->may_rescan is used to guide if
* we should add materialize path over motion
* in the left tree of a join.
*/
config->may_rescan = true;
/* Generate Paths for the subquery */
subroot = subquery_planner(root->glob, subquery,
root,
false,
tuple_fraction,
config);
/* Isolate the params needed by this specific subplan */
plan_params = root->plan_params;
root->plan_params = NIL;
/*
* Select best Path and turn it into a Plan. At least for now, there
* seems no reason to postpone doing that.
*/
final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
/*
* Greenplum specific behavior:
* Here we only need to handle general locus path,
* segmentgeneral is correct because of later processing.
* If we find that it is a general locus path that
* contains volatile target list or havingQual, we should
* turn it into singleQE.
*/
if (CdbPathLocus_IsGeneral(best_path->locus) &&
(contain_volatile_functions((Node *) subroot->parse->havingQual) ||
contain_volatile_functions((Node *) best_path->pathtarget->exprs)))
CdbPathLocus_MakeSingleQE(&(best_path->locus), getgpsegmentCount());
best_path = cdbllize_adjust_init_plan_path(root, best_path);
subroot->curSlice = palloc0(sizeof(PlanSlice));
subroot->curSlice->gangType = GANGTYPE_UNALLOCATED;
plan = create_plan(subroot, best_path, subroot->curSlice);
/* Decorate the top node of the plan with a Flow node. */
plan->flow = cdbpathtoplan_create_flow(subroot, best_path->locus);
/* And convert to SubPlan or InitPlan format. */
result = build_subplan(root, plan, subroot, plan_params,
subLinkType, subLinkId,
testexpr, true, isTopQual);
/*
* If it's a correlated EXISTS with an unimportant targetlist, we might be
* able to transform it to the equivalent of an IN and then implement it
* by hashing. We don't have enough information yet to tell which way is
* likely to be better (it depends on the expected number of executions of
* the EXISTS qual, and we are much too early in planning the outer query
* to be able to guess that). So we generate both plans, if possible, and
* leave it to the executor to decide which to use.
*/
if (simple_exists && IsA(result, SubPlan))
{
Node *newtestexpr;
List *paramIds;
/* Make a second copy of the original subquery */
subquery = copyObject(orig_subquery);
/* and re-simplify */
simple_exists = simplify_EXISTS_query(root, subquery);
Assert(simple_exists);
/* See if it can be converted to an ANY query */
subquery = convert_EXISTS_to_ANY(root, subquery,
&newtestexpr, ¶mIds);
if (subquery)
{
/* Generate Paths for the ANY subquery; we'll need all rows */
subroot = subquery_planner(root->glob, subquery,
root,
false, 0.0, config);
/* Isolate the params needed by this specific subplan */
plan_params = root->plan_params;
root->plan_params = NIL;
/* Select best Path and turn it into a Plan */
final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
best_path = final_rel->cheapest_total_path;
subroot->curSlice = palloc0(sizeof(PlanSlice));
subroot->curSlice->gangType = GANGTYPE_UNALLOCATED;
plan = create_plan(subroot, best_path, subroot->curSlice);
/* Decorate the top node of the plan with a Flow node. */
plan->flow = cdbpathtoplan_create_flow(subroot, best_path->locus);
/* Now we can check if it'll fit in work_mem */
/* XXX can we check this at the Path stage? */
if (subplan_is_hashable(root, plan))
{
SubPlan *hashplan;
AlternativeSubPlan *asplan;
/* OK, convert to SubPlan format. */
hashplan = castNode(SubPlan,
build_subplan(root, plan, subroot,
plan_params,
ANY_SUBLINK, 0,
newtestexpr,
false, true));
/* Check we got what we expected */
Assert(hashplan->parParam == NIL);
Assert(hashplan->useHashTable);
/* build_subplan won't have filled in paramIds */
hashplan->paramIds = paramIds;
/* Leave it to the executor to decide which plan to use */
asplan = makeNode(AlternativeSubPlan);
asplan->subplans = list_make2(result, hashplan);
result = (Node *) asplan;
}
}
}
return result;
}
/*
* Build a SubPlan node given the raw inputs --- subroutine for make_subplan
*
* Returns either the SubPlan, or a replacement expression if we decide to
* make it an InitPlan, as explained in the comments for make_subplan.
*/
static Node *
build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
List *plan_params,
SubLinkType subLinkType, int subLinkId,
Node *testexpr, bool adjust_testexpr,
bool unknownEqFalse)
{
Node *result;
SubPlan *splan;
ListCell *lc;
Bitmapset *tmpset;
Bitmapset *plan_param_set;
int paramid;
/*
* Initialize the SubPlan node. Note plan_id, plan_name, and cost fields
* are set further down.
*/
splan = makeNode(SubPlan);
splan->subLinkType = subLinkType;
splan->testexpr = NULL;
splan->paramIds = NIL;
get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
&splan->firstColCollation);
splan->useHashTable = false;
splan->unknownEqFalse = unknownEqFalse;
splan->parallel_safe = plan->parallel_safe;
splan->is_initplan = false;
splan->is_multirow = false;
splan->setParam = NIL;
splan->parParam = NIL;
splan->args = NIL;
splan->extParam = NIL;
plan_param_set = NULL;
/*
* Make parParam and args lists of param IDs and expressions that current
* query level will pass to this child plan.
*/
foreach(lc, plan_params)
{
PlannerParamItem *pitem = (PlannerParamItem *) lfirst(lc);
Node *arg = pitem->item;
/*
* The Var, PlaceHolderVar, or Aggref has already been adjusted to
* have the correct varlevelsup, phlevelsup, or agglevelsup.
*
* If it's a PlaceHolderVar or Aggref, its arguments might contain
* SubLinks, which have not yet been processed (see the comments for
* SS_replace_correlation_vars). Do that now.
*/
if (IsA(arg, PlaceHolderVar) ||
IsA(arg, Aggref))
arg = SS_process_sublinks(root, arg, false);
splan->parParam = lappend_int(splan->parParam, pitem->paramId);
splan->args = lappend(splan->args, arg);
plan_param_set = bms_add_member(plan_param_set, pitem->paramId);
}
/*
* For gpdb, we need extParam to evaluate if we can process initplan
* in ExecutorStart.
*/
if (plan->extParam)
{
tmpset = bms_difference(plan->extParam, plan_param_set);
while ((paramid = bms_first_member(tmpset)) >= 0)
splan->extParam = lappend_int(splan->extParam, paramid);
pfree(tmpset);
}
/*
* Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY,
* ROWCOMPARE, or MULTIEXPR types can be used as initPlans. For EXISTS,
* EXPR, or ARRAY, we return a Param referring to the result of evaluating
* the initPlan. For ROWCOMPARE, we must modify the testexpr tree to
* contain PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted
* by the parser, and then return that tree. For MULTIEXPR, we return a
* null constant: the resjunk targetlist item containing the SubLink does
* not need to return anything useful, since the referencing Params are
* elsewhere.
*/
if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
{
Param *prm;
Assert(testexpr == NULL);
prm = generate_new_exec_param(root, BOOLOID, -1, InvalidOid);
splan->setParam = list_make1_int(prm->paramid);
splan->is_initplan = true;
result = (Node *) prm;
}
else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
{
TargetEntry *te = linitial(plan->targetlist);
Param *prm;
Assert(!te->resjunk);
Assert(testexpr == NULL);
prm = generate_new_exec_param(root,
exprType((Node *) te->expr),
exprTypmod((Node *) te->expr),
exprCollation((Node *) te->expr));
splan->setParam = list_make1_int(prm->paramid);
splan->is_initplan = true;
result = (Node *) prm;
}
else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
{
TargetEntry *te = linitial(plan->targetlist);
Oid arraytype;
Param *prm;
Assert(!te->resjunk);
Assert(testexpr == NULL);
arraytype = get_promoted_array_type(exprType((Node *) te->expr));
if (!OidIsValid(arraytype))
elog(ERROR, "could not find array type for datatype %s",
format_type_be(exprType((Node *) te->expr)));
prm = generate_new_exec_param(root,
arraytype,
exprTypmod((Node *) te->expr),
exprCollation((Node *) te->expr));
splan->setParam = list_make1_int(prm->paramid);
splan->is_initplan = true;
result = (Node *) prm;
}
else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
{
/* Adjust the Params */
List *params;
Assert(testexpr != NULL);
params = generate_subquery_params(root,
plan->targetlist,
&splan->paramIds);
result = convert_testexpr(root,
testexpr,
params);
splan->setParam = list_copy(splan->paramIds);
splan->is_initplan = true;
/*
* The executable expression is returned to become part of the outer
* plan's expression tree; it is not kept in the initplan node.
*/
}
else if (subLinkType == MULTIEXPR_SUBLINK)
{
/*
* Whether it's an initplan or not, it needs to set a PARAM_EXEC Param
* for each output column.
*/
List *params;
Assert(testexpr == NULL);
params = generate_subquery_params(root,
plan->targetlist,
&splan->setParam);
/*
* Save the list of replacement Params in the n'th cell of
* root->multiexpr_params; setrefs.c will use it to replace
* PARAM_MULTIEXPR Params.
*/
while (list_length(root->multiexpr_params) < subLinkId)
root->multiexpr_params = lappend(root->multiexpr_params, NIL);
lc = list_nth_cell(root->multiexpr_params, subLinkId - 1);
Assert(lfirst(lc) == NIL);
lfirst(lc) = params;
/* It can be an initplan if there are no parParams. */
if (splan->parParam == NIL)
{
splan->is_initplan = true;
result = (Node *) makeNullConst(RECORDOID, -1, InvalidOid);
}
else
{
splan->is_initplan = false;
result = (Node *) splan;
}
}
else
{
/*
* Adjust the Params in the testexpr, unless caller said it's not
* needed.
*/
if (testexpr && adjust_testexpr)
{
List *params;
params = generate_subquery_params(root,
plan->targetlist,
&splan->paramIds);
splan->testexpr = convert_testexpr(root,
testexpr,
params);
}
else
splan->testexpr = testexpr;
splan->is_multirow = true; /* CDB: take note. */
/*
* We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
* initPlans, even when they are uncorrelated or undirect correlated,
* because we need to scan the output of the subplan for each outer
* tuple. But if it's a not-direct-correlated IN (= ANY) test, we
* might be able to use a hashtable to avoid comparing all the tuples.
*
* TODO siva - I believe we should've pulled these up to be NL joins.
* We may want to assert that this is never exercised.
*/
if (subLinkType == ANY_SUBLINK &&
splan->parParam == NIL &&
subplan_is_hashable(root, plan) &&
testexpr_is_hashable(splan->testexpr))
splan->useHashTable = true;
/*
* Otherwise, we have the option to tack a Material node onto the top
* of the subplan, to reduce the cost of reading it repeatedly. This
* is pointless for a direct-correlated subplan, since we'd have to
* recompute its results each time anyway. For uncorrelated/undirect
* correlated subplans, we add Material unless the subplan's top plan
* node would materialize its output anyway. Also, if enable_material
* is false, then the user does not want us to materialize anything
* unnecessarily, so we don't.
*/
else if (splan->parParam == NIL && enable_material &&
!ExecMaterializesOutput(nodeTag(plan)))
plan = materialize_finished_plan(root, plan);
result = (Node *) splan;
}
AssertEquivalent(splan->is_initplan, !splan->is_multirow && splan->parParam == NIL);
/*
* Add the subplan and its PlannerInfo to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, plan);
root->glob->subroots = lappend(root->glob->subroots, subroot);
splan->plan_id = list_length(root->glob->subplans);
if (splan->is_initplan)
root->init_plans = lappend(root->init_plans, splan);
/*
* A parameterless subplan (not initplan) should be prepared to handle
* REWIND efficiently. If it has direct parameters then there's no point
* since it'll be reset on each scan anyway; and if it's an initplan then
* there's no point since it won't get re-run without parameter changes
* anyway. The input of a hashed subplan doesn't need REWIND either.
*/
if (splan->parParam == NIL && !splan->is_initplan && !splan->useHashTable)
root->glob->rewindPlanIDs = bms_add_member(root->glob->rewindPlanIDs,
splan->plan_id);
/* Label the subplan for EXPLAIN purposes */
splan->plan_name = palloc(32 + 12 * list_length(splan->setParam));
sprintf(splan->plan_name, "%s %d",
splan->is_initplan ? "InitPlan" : "SubPlan",
splan->plan_id);
if (splan->setParam)
{
char *ptr = splan->plan_name + strlen(splan->plan_name);
ptr += sprintf(ptr, " (returns ");
foreach(lc, splan->setParam)
{
ptr += sprintf(ptr, "$%d%s",
lfirst_int(lc),
lnext(lc) ? "," : ")");
}
}
/* Lastly, fill in the cost estimates for use later */
cost_subplan(root, splan, plan);
return result;
}
/*
* generate_subquery_params: build a list of Params representing the output
* columns of a sublink's sub-select, given the sub-select's targetlist.
*
* We also return an integer list of the paramids of the Params.
*/
static List *
generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds)
{
List *result;
List *ids;
ListCell *lc;
result = ids = NIL;
foreach(lc, tlist)
{
TargetEntry *tent = (TargetEntry *) lfirst(lc);
Param *param;
if (tent->resjunk)
continue;
param = generate_new_exec_param(root,
exprType((Node *) tent->expr),
exprTypmod((Node *) tent->expr),
exprCollation((Node *) tent->expr));
result = lappend(result, param);
ids = lappend_int(ids, param->paramid);
}
*paramIds = ids;
return result;
}
/*
* generate_subquery_vars: build a list of Vars representing the output
* columns of a sublink's sub-select, given the sub-select's targetlist.
* The Vars have the specified varno (RTE index).
*/
List *
generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
{
List *result;
ListCell *lc;
result = NIL;
foreach(lc, tlist)
{
TargetEntry *tent = (TargetEntry *) lfirst(lc);
Var *var;
if (tent->resjunk)
continue;
var = makeVarFromTargetEntry(varno, tent);
result = lappend(result, var);
}
return result;
}
/*
* convert_testexpr: convert the testexpr given by the parser into
* actually executable form. This entails replacing PARAM_SUBLINK Params
* with Params or Vars representing the results of the sub-select. The
* nodes to be substituted are passed in as the List result from
* generate_subquery_params or generate_subquery_vars.
*/
Node *
convert_testexpr(PlannerInfo *root,
Node *testexpr,
List *subst_nodes)
{
convert_testexpr_context context;
context.root = root;
context.subst_nodes = subst_nodes;
return convert_testexpr_mutator(testexpr, &context);
}
static Node *
convert_testexpr_mutator(Node *node,
convert_testexpr_context *context)
{
if (node == NULL)
return NULL;
if (IsA(node, Param))
{
Param *param = (Param *) node;
if (param->paramkind == PARAM_SUBLINK)
{
if (param->paramid <= 0 ||
param->paramid > list_length(context->subst_nodes))
elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
/*
* We copy the list item to avoid having doubly-linked
* substructure in the modified parse tree. This is probably
* unnecessary when it's a Param, but be safe.
*/
return (Node *) copyObject(list_nth(context->subst_nodes,
param->paramid - 1));
}
}
if (IsA(node, SubLink))
{
/*
* If we come across a nested SubLink, it is neither necessary nor
* correct to recurse into it: any PARAM_SUBLINKs we might find inside
* belong to the inner SubLink not the outer. So just return it as-is.
*
* This reasoning depends on the assumption that nothing will pull
* subexpressions into or out of the testexpr field of a SubLink, at
* least not without replacing PARAM_SUBLINKs first. If we did want
* to do that we'd need to rethink the parser-output representation
* altogether, since currently PARAM_SUBLINKs are only unique per
* SubLink not globally across the query. The whole point of
* replacing them with Vars or PARAM_EXEC nodes is to make them
* globally unique before they escape from the SubLink's testexpr.
*
* Note: this can't happen when called during SS_process_sublinks,
* because that recursively processes inner SubLinks first. It can
* happen when called from convert_ANY_sublink_to_join, though.
*/
return node;
}
return expression_tree_mutator(node,
convert_testexpr_mutator,
(void *) context);
}
/*
* subplan_is_hashable: can we implement an ANY subplan by hashing?
*/
static bool
subplan_is_hashable(PlannerInfo *root, Plan *plan)
{
double subquery_size;
/*
* The estimated size of the subquery result must fit in work_mem. (Note:
* we use heap tuple overhead here even though the tuples will actually be
* stored as MinimalTuples; this provides some fudge factor for hashtable
* overhead.)
*/
subquery_size = plan->plan_rows *
(MAXALIGN(plan->plan_width) + MAXALIGN(SizeofHeapTupleHeader));
if (subquery_size > global_work_mem(root))
return false;
return true;
}
/*
* testexpr_is_hashable: is an ANY SubLink's test expression hashable?
*/
static bool
testexpr_is_hashable(Node *testexpr)
{
/*
* The testexpr must be a single OpExpr, or an AND-clause containing only
* OpExprs.
*
* The combining operators must be hashable and strict. The need for
* hashability is obvious, since we want to use hashing. Without
* strictness, behavior in the presence of nulls is too unpredictable. We
* actually must assume even more than plain strictness: they can't yield
* NULL for non-null inputs, either (see nodeSubplan.c). However, hash
* indexes and hash joins assume that too.
*/
if (testexpr && IsA(testexpr, OpExpr))
{
if (hash_ok_operator((OpExpr *) testexpr))
return true;
}
else if (is_andclause(testexpr))
{
ListCell *l;
foreach(l, ((BoolExpr *) testexpr)->args)
{
Node *andarg = (Node *) lfirst(l);
if (!IsA(andarg, OpExpr))
return false;
if (!hash_ok_operator((OpExpr *) andarg))
return false;
}
return true;
}
return false;
}
/*
* Check expression is hashable + strict
*
* We could use op_hashjoinable() and op_strict(), but do it like this to
* avoid a redundant cache lookup.
*/
static bool
hash_ok_operator(OpExpr *expr)
{
Oid opid = expr->opno;
/* quick out if not a binary operator */
if (list_length(expr->args) != 2)
return false;
if (opid == ARRAY_EQ_OP)
{
/* array_eq is strict, but must check input type to ensure hashable */
/* XXX record_eq will need same treatment when it becomes hashable */
Node *leftarg = linitial(expr->args);
return op_hashjoinable(opid, exprType(leftarg));
}
else
{
/* else must look up the operator properties */
HeapTuple tup;
Form_pg_operator optup;
tup = SearchSysCache1(OPEROID, ObjectIdGetDatum(opid));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for operator %u", opid);
optup = (Form_pg_operator) GETSTRUCT(tup);
if (!optup->oprcanhash || !func_strict(optup->oprcode))
{
ReleaseSysCache(tup);
return false;
}
ReleaseSysCache(tup);
return true;
}
}
#if 0
/*
* GPDB doesn't use initplan + CteScan, so running SS_process_ctes will only
* generate unused initplans. Keep commented out to avoid merge conflicts with
* upstream.
*/
/*
* SS_process_ctes: process a query's WITH list
*
* Consider each CTE in the WITH list and either ignore it (if it's an
* unreferenced SELECT), "inline" it to create a regular sub-SELECT-in-FROM,
* or convert it to an initplan.
*
* A side effect is to fill in root->cte_plan_ids with a list that
* parallels root->parse->cteList and provides the subplan ID for
* each CTE's initplan, or a dummy ID (-1) if we didn't make an initplan.
*/
void
SS_process_ctes(PlannerInfo *root)
{
ListCell *lc;
Assert(root->cte_plan_ids == NIL);
foreach(lc, root->parse->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
CmdType cmdType = ((Query *) cte->ctequery)->commandType;
Query *subquery;
PlannerInfo *subroot;
RelOptInfo *final_rel;
Path *best_path;
Plan *plan;
SubPlan *splan;
int paramid;
/*
* Ignore SELECT CTEs that are not actually referenced anywhere.
*/
if (cte->cterefcount == 0 && cmdType == CMD_SELECT)
{
/* Make a dummy entry in cte_plan_ids */
root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
continue;
}
/*
* Consider inlining the CTE (creating RTE_SUBQUERY RTE(s)) instead of
* implementing it as a separately-planned CTE.
*
* We cannot inline if any of these conditions hold:
*
* 1. The user said not to (the CTEMaterializeAlways option).
*
* 2. The CTE is recursive.
*
* 3. The CTE has side-effects; this includes either not being a plain
* SELECT, or containing volatile functions. Inlining might change
* the side-effects, which would be bad.
*
* 4. The CTE is multiply-referenced and contains a self-reference to
* a recursive CTE outside itself. Inlining would result in multiple
* recursive self-references, which we don't support.
*
* Otherwise, we have an option whether to inline or not. That should
* always be a win if there's just a single reference, but if the CTE
* is multiply-referenced then it's unclear: inlining adds duplicate
* computations, but the ability to absorb restrictions from the outer
* query level could outweigh that. We do not have nearly enough
* information at this point to tell whether that's true, so we let
* the user express a preference. Our default behavior is to inline
* only singly-referenced CTEs, but a CTE marked CTEMaterializeNever
* will be inlined even if multiply referenced.
*
* Note: we check for volatile functions last, because that's more
* expensive than the other tests needed.
*/
if ((cte->ctematerialized == CTEMaterializeNever ||
(cte->ctematerialized == CTEMaterializeDefault &&
cte->cterefcount == 1)) &&
!cte->cterecursive &&
cmdType == CMD_SELECT &&
!contain_dml(cte->ctequery) &&
(cte->cterefcount <= 1 ||
!contain_outer_selfref(cte->ctequery)) &&
!contain_volatile_functions(cte->ctequery))
{
inline_cte(root, cte);
/* Make a dummy entry in cte_plan_ids */
root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
continue;
}
/*
* Copy the source Query node. Probably not necessary, but let's keep
* this similar to make_subplan.
*/
subquery = (Query *) copyObject(cte->ctequery);
/* plan_params should not be in use in current query level */
Assert(root->plan_params == NIL);
/*
* Generate Paths for the CTE query. Always plan for full retrieval
* --- we don't have enough info to predict otherwise.
*/
subroot = subquery_planner(root->glob, subquery,
root,
cte->cterecursive, 0.0,
root->config);
/*
* Since the current query level doesn't yet contain any RTEs, it
* should not be possible for the CTE to have requested parameters of
* this level.
*/
if (root->plan_params)
elog(ERROR, "unexpected outer reference in CTE query");
/*
* Select best Path and turn it into a Plan. At least for now, there
* seems no reason to postpone doing that.
*/
final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
best_path = final_rel->cheapest_total_path;
plan = create_plan(subroot, best_path);
/*
* Make a SubPlan node for it. This is just enough unlike
* build_subplan that we can't share code.
*
* Note plan_id, plan_name, and cost fields are set further down.
*/
splan = makeNode(SubPlan);
splan->subLinkType = CTE_SUBLINK;
splan->testexpr = NULL;
splan->paramIds = NIL;
get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
&splan->firstColCollation);
splan->useHashTable = false;
splan->unknownEqFalse = false;
/*
* CTE scans are not considered for parallelism (cf
* set_rel_consider_parallel), and even if they were, initPlans aren't
* parallel-safe.
*/
splan->parallel_safe = false;
splan->setParam = NIL;
splan->parParam = NIL;
splan->args = NIL;
/*
* The node can't have any inputs (since it's an initplan), so the
* parParam and args lists remain empty. (It could contain references
* to earlier CTEs' output param IDs, but CTE outputs are not
* propagated via the args list.)
*/
/*
* Assign a param ID to represent the CTE's output. No ordinary
* "evaluation" of this param slot ever happens, but we use the param
* ID for setParam/chgParam signaling just as if the CTE plan were
* returning a simple scalar output. (Also, the executor abuses the
* ParamExecData slot for this param ID for communication among
* multiple CteScan nodes that might be scanning this CTE.)
*/
paramid = assign_special_exec_param(root);
splan->setParam = list_make1_int(paramid);
/*
* Add the subplan and its PlannerInfo to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, plan);
root->glob->subroots = lappend(root->glob->subroots, subroot);
splan->plan_id = list_length(root->glob->subplans);
root->init_plans = lappend(root->init_plans, splan);
root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
/* Label the subplan for EXPLAIN purposes */
splan->plan_name = psprintf("CTE %s", cte->ctename);
/* Lastly, fill in the cost estimates for use later */
cost_subplan(root, splan, plan);
}
}
/*
* contain_dml: is any subquery not a plain SELECT?
*
* We reject SELECT FOR UPDATE/SHARE as well as INSERT etc.
*/
static bool
contain_dml(Node *node)
{
return contain_dml_walker(node, NULL);
}
static bool
contain_dml_walker(Node *node, void *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
Query *query = (Query *) node;
if (query->commandType != CMD_SELECT ||
query->rowMarks != NIL)
return true;
return query_tree_walker(query, contain_dml_walker, context, 0);
}
return expression_tree_walker(node, contain_dml_walker, context);
}
/*
* contain_outer_selfref: is there an external recursive self-reference?
*/
static bool
contain_outer_selfref(Node *node)
{
Index depth = 0;
/*
* We should be starting with a Query, so that depth will be 1 while
* examining its immediate contents.
*/
Assert(IsA(node, Query));
return contain_outer_selfref_walker(node, &depth);
}
static bool
contain_outer_selfref_walker(Node *node, Index *depth)
{
if (node == NULL)
return false;
if (IsA(node, RangeTblEntry))
{
RangeTblEntry *rte = (RangeTblEntry *) node;
/*
* Check for a self-reference to a CTE that's above the Query that our
* search started at.
*/
if (rte->rtekind == RTE_CTE &&
rte->self_reference &&
rte->ctelevelsup >= *depth)
return true;
return false; /* allow range_table_walker to continue */
}
if (IsA(node, Query))
{
/* Recurse into subquery, tracking nesting depth properly */
Query *query = (Query *) node;
bool result;
(*depth)++;
result = query_tree_walker(query, contain_outer_selfref_walker,
(void *) depth, QTW_EXAMINE_RTES_BEFORE);
(*depth)--;
return result;
}
return expression_tree_walker(node, contain_outer_selfref_walker,
(void *) depth);
}
/*
* inline_cte: convert RTE_CTE references to given CTE into RTE_SUBQUERYs
*/
static void
inline_cte(PlannerInfo *root, CommonTableExpr *cte)
{
struct inline_cte_walker_context context;
context.ctename = cte->ctename;
/* Start at levelsup = -1 because we'll immediately increment it */
context.levelsup = -1;
context.refcount = cte->cterefcount;
context.ctequery = castNode(Query, cte->ctequery);
(void) inline_cte_walker((Node *) root->parse, &context);
/* Assert we replaced all references */
Assert(context.refcount == 0);
}
static bool
inline_cte_walker(Node *node, inline_cte_walker_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
Query *query = (Query *) node;
context->levelsup++;
/*
* Visit the query's RTE nodes after their contents; otherwise
* query_tree_walker would descend into the newly inlined CTE query,
* which we don't want.
*/
(void) query_tree_walker(query, inline_cte_walker, context,
QTW_EXAMINE_RTES_AFTER);
context->levelsup--;
return false;
}
else if (IsA(node, RangeTblEntry))
{
RangeTblEntry *rte = (RangeTblEntry *) node;
if (rte->rtekind == RTE_CTE &&
strcmp(rte->ctename, context->ctename) == 0 &&
rte->ctelevelsup == context->levelsup)
{
/*
* Found a reference to replace. Generate a copy of the CTE query
* with appropriate level adjustment for outer references (e.g.,
* to other CTEs).
*/
Query *newquery = copyObject(context->ctequery);
if (context->levelsup > 0)
IncrementVarSublevelsUp((Node *) newquery, context->levelsup, 1);
/*
* Convert the RTE_CTE RTE into a RTE_SUBQUERY.
*
* Historically, a FOR UPDATE clause has been treated as extending
* into views and subqueries, but not into CTEs. We preserve this
* distinction by not trying to push rowmarks into the new
* subquery.
*/
rte->rtekind = RTE_SUBQUERY;
rte->subquery = newquery;
rte->security_barrier = false;
/* Zero out CTE-specific fields */
rte->ctename = NULL;
rte->ctelevelsup = 0;
rte->self_reference = false;
rte->coltypes = NIL;
rte->coltypmods = NIL;
rte->colcollations = NIL;
/* Count the number of replacements we've done */
context->refcount--;
}
return false;
}
return expression_tree_walker(node, inline_cte_walker, context);
}
#endif
/*
* convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
*
* The caller has found an ANY SubLink at the top level of one of the query's
* qual clauses, but has not checked the properties of the SubLink further.
* Decide whether it is appropriate to process this SubLink in join style.
* If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
* be converted to a join.
*
* The only non-obvious input parameter is available_rels: this is the set
* of query rels that can safely be referenced in the sublink expression.
* (We must restrict this to avoid changing the semantics when a sublink
* is present in an outer join's ON qual.) The conversion must fail if
* the converted qual would reference any but these parent-query relids.
*
* On success, the returned JoinExpr has larg = NULL and rarg = the jointree
* item representing the pulled-up subquery. The caller must set larg to
* represent the relation(s) on the lefthand side of the new join, and insert
* the JoinExpr into the upper query's jointree at an appropriate place
* (typically, where the lefthand relation(s) had been). Note that the
* passed-in SubLink must also be removed from its original position in the
* query quals, since the quals of the returned JoinExpr replace it.
* (Notionally, we replace the SubLink with a constant TRUE, then elide the
* redundant constant from the qual.)
*
* On success, the caller is also responsible for recursively applying
* pull_up_sublinks processing to the rarg and quals of the returned JoinExpr.
* (On failure, there is no need to do anything, since pull_up_sublinks will
* be applied when we recursively plan the sub-select.)
*
* Side effects of a successful conversion include adding the SubLink's
* subselect to the query's rangetable, so that it can be referenced in
* the JoinExpr's rarg.
*/
JoinExpr *
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
Relids available_rels)
{
JoinExpr *result;
Query *parse = root->parse;
Query *subselect = (Query *) sublink->subselect;
Relids upper_varnos;
int rtindex;
RangeTblEntry *rte;
RangeTblRef *rtr;
List *subquery_vars;
Node *quals;
bool correlated;
ParseState *pstate;
Assert(sublink->subLinkType == ANY_SUBLINK);
Assert(IsA(subselect, Query));
/*
* If deeply correlated, then don't pull it up
*/
if (IsSubqueryMultiLevelCorrelated(subselect))
return NULL;
/*
* If uncorrelated, and no Var nodes on lhs, the subquery will be executed
* only once. It should become an InitPlan, but make_subplan() doesn't
* handle that case, so just flatten it for now.
* CDB TODO: Let it become an InitPlan, so its QEs can be recycled.
*/
correlated = contain_vars_of_level_or_above(sublink->subselect, 1);
if (correlated)
{
/*
* Under certain conditions, we cannot pull up the subquery as a join.
*/
if (!is_simple_subquery(root, subselect, NULL, NULL))
return NULL;
/*
* Do not pull subqueries with correlation in a func expr in the from
* clause of the subselect
*/
if (has_correlation_in_funcexpr_rte(subselect->rtable))
return NULL;
if (contain_subplans(subselect->jointree->quals))
return NULL;
}
/*
* The test expression must contain some Vars of the parent query,
* else it's not gonna be a join. (Note that it won't have Vars
* referring to the subquery, rather Params.)
*/
upper_varnos = pull_varnos(sublink->testexpr);
if (bms_is_empty(upper_varnos))
return NULL;
/*
* However, it can't refer to anything outside available_rels.
*/
if (!bms_is_subset(upper_varnos, available_rels))
return NULL;
/*
* The combining operators and left-hand expressions mustn't be volatile.
*/
if (contain_volatile_functions(sublink->testexpr))
return NULL;
/* Create a dummy ParseState for addRangeTableEntryForSubquery */
pstate = make_parsestate(NULL);
/*
* Okay, pull up the sub-select into upper range table.
*
* We rely here on the assumption that the outer query has no references
* to the inner (necessarily true, other than the Vars that we build
* below). Therefore this is a lot easier than what pull_up_subqueries has
* to go through.
*
* If the subquery is correlated, i.e. it refers to any Vars of the
* parent query, mark it as lateral.
*/
rte = addRangeTableEntryForSubquery(pstate,
subselect,
makeAlias("ANY_subquery", NIL),
correlated, /* lateral */
false);
parse->rtable = lappend(parse->rtable, rte);
rtindex = list_length(parse->rtable);
/*
* Form a RangeTblRef for the pulled-up sub-select.
*/
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
/*
* Build a list of Vars representing the subselect outputs.
*/
subquery_vars = generate_subquery_vars(root,
subselect->targetList,
rtindex);
/*
* Build the new join's qual expression, replacing Params with these Vars.
*/
quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
result = makeNode(JoinExpr);
result->jointype = JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
result->rarg = (Node *) rtr;
result->usingClause = NIL;
result->quals = quals;
result->alias = NULL;
result->rtindex = 0;
return result;
}
/*
* convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
*
* The API of this function is identical to convert_ANY_sublink_to_join's,
* except that we also support the case where the caller has found NOT EXISTS,
* so we need an additional input parameter "under_not".
*/
JoinExpr *
convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
bool under_not, Relids available_rels)
{
JoinExpr *result;
Query *parse = root->parse;
Query *subselect = (Query *) sublink->subselect;
Node *whereClause;
int rtoffset;
int varno;
Relids clause_varnos;
Relids upper_varnos;
Assert(sublink->subLinkType == EXISTS_SUBLINK);
/*
* Can't flatten if it contains WITH. (We could arrange to pull up the
* WITH into the parent query's cteList, but that risks changing the
* semantics, since a WITH ought to be executed once per associated query
* call.) Note that convert_ANY_sublink_to_join doesn't have to reject
* this case, since it just produces a subquery RTE that doesn't have to
* get flattened into the parent query.
*/
if (subselect->cteList)
return NULL;
/*
* Copy the subquery so we can modify it safely (see comments in
* make_subplan).
*/
subselect = copyObject(subselect);
/*
* See if the subquery can be simplified based on the knowledge that it's
* being used in EXISTS(). If we aren't able to get rid of its
* targetlist, we have to fail, because the pullup operation leaves us
* with noplace to evaluate the targetlist.
*/
if (!simplify_EXISTS_query(root, subselect))
return NULL;
/*
* Separate out the WHERE clause. (We could theoretically also remove
* top-level plain JOIN/ON clauses, but it's probably not worth the
* trouble.)
*/
whereClause = subselect->jointree->quals;
subselect->jointree->quals = NULL;
/*
* The rest of the sub-select must not refer to any Vars of the parent
* query. (Vars of higher levels should be okay, though.)
*/
if (contain_vars_of_level((Node *) subselect, 1))
return NULL;
/*
* On the other hand, the WHERE clause must contain some Vars of the
* parent query, else it's not gonna be a join.
*/
if (!contain_vars_of_level(whereClause, 1))
return NULL;
/*
* We don't risk optimizing if the WHERE clause is volatile, either.
*/
if (contain_volatile_functions(whereClause))
return NULL;
/*
* The subquery must have a nonempty jointree, but we can make it so.
*/
replace_empty_jointree(subselect);
/*
* Prepare to pull up the sub-select into top range table.
*
* We rely here on the assumption that the outer query has no references
* to the inner (necessarily true). Therefore this is a lot easier than
* what pull_up_subqueries has to go through.
*
* In fact, it's even easier than what convert_ANY_sublink_to_join has to
* do. The machinations of simplify_EXISTS_query ensured that there is
* nothing interesting in the subquery except an rtable and jointree, and
* even the jointree FromExpr no longer has quals. So we can just append
* the rtable to our own and use the FromExpr in our jointree. But first,
* adjust all level-zero varnos in the subquery to account for the rtable
* merger.
*/
rtoffset = list_length(parse->rtable);
OffsetVarNodes((Node *) subselect, rtoffset, 0);
OffsetVarNodes(whereClause, rtoffset, 0);
/*
* Upper-level vars in subquery will now be one level closer to their
* parent than before; in particular, anything that had been level 1
* becomes level zero.
*/
IncrementVarSublevelsUp((Node *) subselect, -1, 1);
IncrementVarSublevelsUp(whereClause, -1, 1);
/*
* Now that the WHERE clause is adjusted to match the parent query
* environment, we can easily identify all the level-zero rels it uses.
* The ones <= rtoffset belong to the upper query; the ones > rtoffset do
* not.
*/
clause_varnos = pull_varnos(whereClause);
upper_varnos = NULL;
while ((varno = bms_first_member(clause_varnos)) >= 0)
{
if (varno <= rtoffset)
upper_varnos = bms_add_member(upper_varnos, varno);
}
bms_free(clause_varnos);
Assert(!bms_is_empty(upper_varnos));
/*
* Now that we've got the set of upper-level varnos, we can make the last
* check: only available_rels can be referenced.
*/
if (!bms_is_subset(upper_varnos, available_rels))
return NULL;
/* Now we can attach the modified subquery rtable to the parent */
parse->rtable = list_concat(parse->rtable, subselect->rtable);
/*
* And finally, build the JoinExpr node.
*/
result = makeNode(JoinExpr);
result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
/* flatten out the FromExpr node if it's useless */
if (list_length(subselect->jointree->fromlist) == 1)
result->rarg = (Node *) linitial(subselect->jointree->fromlist);
else
result->rarg = (Node *) subselect->jointree;
result->usingClause = NIL;
result->quals = whereClause;
result->alias = NULL;
result->rtindex = 0; /* we don't need an RTE for it */
return result;
}
/*
* simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
*
* The only thing that matters about an EXISTS query is whether it returns
* zero or more than zero rows. Therefore, we can remove certain SQL features
* that won't affect that. The only part that is really likely to matter in
* typical usage is simplifying the targetlist: it's a common habit to write
* "SELECT * FROM" even though there is no need to evaluate any columns.
*
* Note: by suppressing the targetlist we could cause an observable behavioral
* change, namely that any errors that might occur in evaluating the tlist
* won't occur, nor will other side-effects of volatile functions. This seems
* unlikely to bother anyone in practice.
*
* Returns true if was able to discard the targetlist, else false.
*/
static bool
simplify_EXISTS_query(PlannerInfo *root, Query *query)
{
/*
* PostgreSQL:
*
* We don't try to simplify at all if the query uses set operations,
* aggregates, grouping sets, SRFs, modifying CTEs, HAVING, OFFSET, or FOR
* UPDATE/SHARE; none of these seem likely in normal usage and their
* possible effects are complex. (Note: we could ignore an "OFFSET 0"
* clause, but that traditionally is used as an optimization fence, so we
* don't.)
*
* In GPDB, we try a bit harder: Try to demote HAVING to WHERE, in case
* there are no aggregates or volatile functions. If that fails, only
* then give up. Also, just discard any window functions; they
* shouldn't affect the number of rows returned.
*/
if (query->commandType != CMD_SELECT ||
query->setOperations ||
#if 0
query->hasAggs ||
#endif
query->groupingSets ||
#if 0
query->hasWindowFuncs ||
query->havingQual ||
#endif
query->hasTargetSRFs ||
query->hasModifyingCTE ||
query->limitOffset ||
query->rowMarks)
return false;
/*
* LIMIT with a constant positive (or NULL) value doesn't affect the
* semantics of EXISTS, so let's ignore such clauses. This is worth doing
* because people accustomed to certain other DBMSes may be in the habit
* of writing EXISTS(SELECT ... LIMIT 1) as an optimization. If there's a
* LIMIT with anything else as argument, though, we can't simplify.
*/
if (query->limitCount)
{
/*
* The LIMIT clause has not yet been through eval_const_expressions,
* so we have to apply that here. It might seem like this is a waste
* of cycles, since the only case plausibly worth worrying about is
* "LIMIT 1" ... but what we'll actually see is "LIMIT int8(1::int4)",
* so we have to fold constants or we're not going to recognize it.
*/
Node *node = eval_const_expressions(root, query->limitCount);
Const *limit;
/* Might as well update the query if we simplified the clause. */
query->limitCount = node;
if (!IsA(node, Const))
return false;
limit = (Const *) node;
Assert(limit->consttype == INT8OID);
if (!limit->constisnull && DatumGetInt64(limit->constvalue) <= 0)
return false;
/* Whether or not the targetlist is safe, we can drop the LIMIT. */
query->limitCount = NULL;
}
if (query->havingQual)
{
/*
* If HAVING has no aggregates and volatile functions, demote
* it to WHERE.
* Note: In addition to these rules, subquery_planner() also
* checks if HAVING has subplans, which is not relevant here as
* there are not going to be any subplans at this stage.
*/
if (!contain_aggs_of_level(query->havingQual, 0) &&
!contain_volatile_functions(query->havingQual))
{
query->jointree->quals = make_and_qual(query->jointree->quals,
query->havingQual);
query->havingQual = NULL;
query->hasAggs = false;
}
else
return false;
}
/*
* Otherwise, we can throw away the targetlist, as well as any GROUP,
* WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
* change a nonzero-rows result to zero rows or vice versa. (Furthermore,
* since our parsetree representation of these clauses depends on the
* targetlist, we'd better throw them away if we drop the targetlist.)
*/
query->targetList = NIL;
/*
* Delete GROUP BY if no aggregates.
*
* Note: It's important that we don't clear hasAggs, even though we
* removed any possible aggregates from the targetList! If you have a
* subquery like "SELECT SUM(foo) ...", we don't need to compute the sum,
* but we must still aggregate all the rows, and return a single row,
* regardless of how many input rows there are. (In particular, even
* if there are no input rows).
*/
if (!query->hasAggs)
query->groupClause = NIL;
query->windowClause = NIL;
query->distinctClause = NIL;
query->sortClause = NIL;
query->hasDistinctOn = false;
return true;
}
/*
* remove_useless_EXISTS_sublink
* Check if the EXISTS sublink doesn't actually need to be executed at all,
* and return TRUE/FALSE directly for it in that case. Otherwise return
* NULL.
*/
Node *
remove_useless_EXISTS_sublink(PlannerInfo *root, Query *subselect, bool under_not)
{
/*
* Can't flatten if it contains WITH. (We could arrange to pull up the
* WITH into the parent query's cteList, but that risks changing the
* semantics, since a WITH ought to be executed once per associated query
* call.) Note that convert_ANY_sublink_to_join doesn't have to reject
* this case, since it just produces a subquery RTE that doesn't have to
* get flattened into the parent query.
*/
if (subselect->cteList)
return NULL;
/*
* Copy the subquery so we can modify it safely (see comments in
* make_subplan).
*/
subselect = copyObject(subselect);
/*
* 'LIMIT n' makes EXISTS false when n <= 0, and doesn't affect the
* outcome when n > 0.
*/
if (subselect->limitCount)
{
Node *node = eval_const_expressions(root, subselect->limitCount);
Const *limit;
subselect->limitCount = node;
if (!IsA(node, Const))
return NULL;
limit = (Const *) node;
Assert(limit->consttype == INT8OID);
if (!limit->constisnull && DatumGetInt64(limit->constvalue) <= 0)
return makeBoolConst(under_not, false);
subselect->limitCount = NULL;
}
/*
* If subquery has aggregates without GROUP BY or HAVING, its result is
* exactly one row (assuming no errors), unless that row is discarded by
* LIMIT/OFFSET.
*/
if (subselect->hasAggs &&
subselect->groupClause == NIL &&
subselect->havingQual == NULL)
{
/*
* 'OFFSET m' falsifies EXISTS for m >= 1, and doesn't affect the
* outcome for m < 1, given that the subquery yields at most one row.
*/
if (subselect->limitOffset)
{
Node *node = eval_const_expressions(root, subselect->limitOffset);
Const *limit;
subselect->limitOffset = node;
if (!IsA(node, Const))
return NULL;
limit = (Const *) node;
Assert(limit->consttype == INT8OID);
if (!limit->constisnull && DatumGetInt64(limit->constvalue) > 0)
return makeBoolConst(under_not, false);
}
return makeBoolConst(!under_not, false);
}
return NULL;
}
/*
* convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
*
* The subselect is expected to be a fresh copy that we can munge up,
* and to have been successfully passed through simplify_EXISTS_query.
*
* On success, the modified subselect is returned, and we store a suitable
* upper-level test expression at *testexpr, plus a list of the subselect's
* output Params at *paramIds. (The test expression is already Param-ified
* and hence need not go through convert_testexpr, which is why we have to
* deal with the Param IDs specially.)
*
* On failure, returns NULL.
*/
static Query *
convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
Node **testexpr, List **paramIds)
{
Node *whereClause;
List *leftargs,
*rightargs,
*opids,
*opcollations,
*newWhere,
*tlist,
*testlist,
*paramids;
ListCell *lc,
*rc,
*oc,
*cc;
AttrNumber resno;
/*
* Query must not require a targetlist, since we have to insert a new one.
* Caller should have dealt with the case already.
*/
Assert(subselect->targetList == NIL);
/*
* Separate out the WHERE clause. (We could theoretically also remove
* top-level plain JOIN/ON clauses, but it's probably not worth the
* trouble.)
*/
whereClause = subselect->jointree->quals;
subselect->jointree->quals = NULL;
/*
* The rest of the sub-select must not refer to any Vars of the parent
* query. (Vars of higher levels should be okay, though.)
*
* Note: we need not check for Aggs separately because we know the
* sub-select is as yet unoptimized; any uplevel Agg must therefore
* contain an uplevel Var reference. This is not the case below ...
*/
if (contain_vars_of_level((Node *) subselect, 1))
return NULL;
/*
* We don't risk optimizing if the WHERE clause is volatile, either.
*/
if (contain_volatile_functions(whereClause))
return NULL;
/*
* Clean up the WHERE clause by doing const-simplification etc on it.
* Aside from simplifying the processing we're about to do, this is
* important for being able to pull chunks of the WHERE clause up into the
* parent query. Since we are invoked partway through the parent's
* preprocess_expression() work, earlier steps of preprocess_expression()
* wouldn't get applied to the pulled-up stuff unless we do them here. For
* the parts of the WHERE clause that get put back into the child query,
* this work is partially duplicative, but it shouldn't hurt.
*
* Note: we do not run flatten_join_alias_vars. This is OK because any
* parent aliases were flattened already, and we're not going to pull any
* child Vars (of any description) into the parent.
*
* Note: passing the parent's root to eval_const_expressions is
* technically wrong, but we can get away with it since only the
* boundParams (if any) are used, and those would be the same in a
* subroot.
*/
whereClause = eval_const_expressions(root, whereClause);
whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);
whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
/*
* We now have a flattened implicit-AND list of clauses, which we try to
* break apart into "outervar = innervar" hash clauses. Anything that
* can't be broken apart just goes back into the newWhere list. Note that
* we aren't trying hard yet to ensure that we have only outer or only
* inner on each side; we'll check that if we get to the end.
*/
leftargs = rightargs = opids = opcollations = newWhere = NIL;
foreach(lc, (List *) whereClause)
{
OpExpr *expr = (OpExpr *) lfirst(lc);
if (IsA(expr, OpExpr) &&
hash_ok_operator(expr))
{
Node *leftarg = (Node *) linitial(expr->args);
Node *rightarg = (Node *) lsecond(expr->args);
if (contain_vars_of_level(leftarg, 1))
{
leftargs = lappend(leftargs, leftarg);
rightargs = lappend(rightargs, rightarg);
opids = lappend_oid(opids, expr->opno);
opcollations = lappend_oid(opcollations, expr->inputcollid);
continue;
}
if (contain_vars_of_level(rightarg, 1))
{
/*
* We must commute the clause to put the outer var on the
* left, because the hashing code in nodeSubplan.c expects
* that. This probably shouldn't ever fail, since hashable
* operators ought to have commutators, but be paranoid.
*/
expr->opno = get_commutator(expr->opno);
if (OidIsValid(expr->opno) && hash_ok_operator(expr))
{
leftargs = lappend(leftargs, rightarg);
rightargs = lappend(rightargs, leftarg);
opids = lappend_oid(opids, expr->opno);
opcollations = lappend_oid(opcollations, expr->inputcollid);
continue;
}
/* If no commutator, no chance to optimize the WHERE clause */
return NULL;
}
}
/* Couldn't handle it as a hash clause */
newWhere = lappend(newWhere, expr);
}
/*
* If we didn't find anything we could convert, fail.
*/
if (leftargs == NIL)
return NULL;
/*
* There mustn't be any parent Vars or Aggs in the stuff that we intend to
* put back into the child query. Note: you might think we don't need to
* check for Aggs separately, because an uplevel Agg must contain an
* uplevel Var in its argument. But it is possible that the uplevel Var
* got optimized away by eval_const_expressions. Consider
*
* SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
*/
if (contain_vars_of_level((Node *) newWhere, 1) ||
contain_vars_of_level((Node *) rightargs, 1))
return NULL;
if (root->parse->hasAggs &&
(contain_aggs_of_level((Node *) newWhere, 1) ||
contain_aggs_of_level((Node *) rightargs, 1)))
return NULL;
/*
* And there can't be any child Vars in the stuff we intend to pull up.
* (Note: we'd need to check for child Aggs too, except we know the child
* has no aggs at all because of simplify_EXISTS_query's check. The same
* goes for window functions.)
*/
if (contain_vars_of_level((Node *) leftargs, 0))
return NULL;
/*
* Also reject sublinks in the stuff we intend to pull up. (It might be
* possible to support this, but doesn't seem worth the complication.)
*/
if (contain_subplans((Node *) leftargs))
return NULL;
/*
* Okay, adjust the sublevelsup in the stuff we're pulling up.
*/
IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
/*
* Put back any child-level-only WHERE clauses.
*/
if (newWhere)
subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
/*
* Build a new targetlist for the child that emits the expressions we
* need. Concurrently, build a testexpr for the parent using Params to
* reference the child outputs. (Since we generate Params directly here,
* there will be no need to convert the testexpr in build_subplan.)
*/
tlist = testlist = paramids = NIL;
resno = 1;
forfour(lc, leftargs, rc, rightargs, oc, opids, cc, opcollations)
{
Node *leftarg = (Node *) lfirst(lc);
Node *rightarg = (Node *) lfirst(rc);
Oid opid = lfirst_oid(oc);
Oid opcollation = lfirst_oid(cc);
Param *param;
param = generate_new_exec_param(root,
exprType(rightarg),
exprTypmod(rightarg),
exprCollation(rightarg));
tlist = lappend(tlist,
makeTargetEntry((Expr *) rightarg,
resno++,
NULL,
false));
testlist = lappend(testlist,
make_opclause(opid, BOOLOID, false,
(Expr *) leftarg, (Expr *) param,
InvalidOid, opcollation));
paramids = lappend_int(paramids, param->paramid);
}
/* Put everything where it should go, and we're done */
subselect->targetList = tlist;
*testexpr = (Node *) make_ands_explicit(testlist);
*paramIds = paramids;
return subselect;
}
/*
* Replace correlation vars (uplevel vars) with Params.
*
* Uplevel PlaceHolderVars and aggregates are replaced, too.
*
* Note: it is critical that this runs immediately after SS_process_sublinks.
* Since we do not recurse into the arguments of uplevel PHVs and aggregates,
* they will get copied to the appropriate subplan args list in the parent
* query with uplevel vars not replaced by Params, but only adjusted in level
* (see replace_outer_placeholdervar and replace_outer_agg). That's exactly
* what we want for the vars of the parent level --- but if a PHV's or
* aggregate's argument contains any further-up variables, they have to be
* replaced with Params in their turn. That will happen when the parent level
* runs SS_replace_correlation_vars. Therefore it must do so after expanding
* its sublinks to subplans. And we don't want any steps in between, else
* those steps would never get applied to the argument expressions, either in
* the parent or the child level.
*
* Another fairly tricky thing going on here is the handling of SubLinks in
* the arguments of uplevel PHVs/aggregates. Those are not touched inside the
* intermediate query level, either. Instead, SS_process_sublinks recurses on
* them after copying the PHV or Aggref expression into the parent plan level
* (this is actually taken care of in build_subplan).
*/
Node *
SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
{
/* No setup needed for tree walk, so away we go */
return replace_correlation_vars_mutator(expr, root);
}
static Node *
replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
{
if (node == NULL)
return NULL;
if (IsA(node, Var))
{
if (((Var *) node)->varlevelsup > 0)
return (Node *) replace_outer_var(root, (Var *) node);
}
if (IsA(node, PlaceHolderVar))
{
if (((PlaceHolderVar *) node)->phlevelsup > 0)
return (Node *) replace_outer_placeholdervar(root,
(PlaceHolderVar *) node);
}
if (IsA(node, Aggref))
{
if (((Aggref *) node)->agglevelsup > 0)
return (Node *) replace_outer_agg(root, (Aggref *) node);
}
if (IsA(node, GroupingFunc))
{
if (((GroupingFunc *) node)->agglevelsup > 0)
return (Node *) replace_outer_grouping(root, (GroupingFunc *) node);
}
if (IsA(node, GroupId))
{
if (((GroupId *) node)->agglevelsup > 0)
return (Node *) replace_outer_group_id(root, (GroupId *) node);
}
return expression_tree_mutator(node,
replace_correlation_vars_mutator,
(void *) root);
}
/*
* Expand SubLinks to SubPlans in the given expression.
*
* The isQual argument tells whether or not this expression is a WHERE/HAVING
* qualifier expression. If it is, any sublinks appearing at top level need
* not distinguish FALSE from UNKNOWN return values.
*/
Node *
SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual)
{
process_sublinks_context context;
context.root = root;
context.isTopQual = isQual;
return process_sublinks_mutator(expr, &context);
}
static Node *
process_sublinks_mutator(Node *node, process_sublinks_context *context)
{
process_sublinks_context locContext;
locContext.root = context->root;
if (node == NULL)
return NULL;
if (IsA(node, SubLink))
{
SubLink *sublink = (SubLink *) node;
Node *testexpr;
/*
* First, recursively process the lefthand-side expressions, if any.
* They're not top-level anymore.
*/
locContext.isTopQual = false;
testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
/*
* Now build the SubPlan node and make the expr to return.
*/
return make_subplan(context->root,
(Query *) sublink->subselect,
sublink->subLinkType,
sublink->subLinkId,
testexpr,
context->isTopQual);
}
/*
* Don't recurse into the arguments of an outer PHV or aggregate here. Any
* SubLinks in the arguments have to be dealt with at the outer query
* level; they'll be handled when build_subplan collects the PHV or Aggref
* into the arguments to be passed down to the current subplan.
*/
if (IsA(node, PlaceHolderVar))
{
if (((PlaceHolderVar *) node)->phlevelsup > 0)
return node;
}
else if (IsA(node, Aggref))
{
if (((Aggref *) node)->agglevelsup > 0)
return node;
}
/*
* We should never see a SubPlan expression in the input (since this is
* the very routine that creates 'em to begin with). We shouldn't find
* ourselves invoked directly on a Query, either.
*/
Assert(!IsA(node, SubPlan));
Assert(!IsA(node, AlternativeSubPlan));
Assert(!IsA(node, Query));
/*
* Because make_subplan() could return an AND or OR clause, we have to
* take steps to preserve AND/OR flatness of a qual. We assume the input
* has been AND/OR flattened and so we need no recursion here.
*
* (Due to the coding here, we will not get called on the List subnodes of
* an AND; and the input is *not* yet in implicit-AND format. So no check
* is needed for a bare List.)
*
* Anywhere within the top-level AND/OR clause structure, we can tell
* make_subplan() that NULL and FALSE are interchangeable. So isTopQual
* propagates down in both cases. (Note that this is unlike the meaning
* of "top level qual" used in most other places in Postgres.)
*/
if (is_andclause(node))
{
List *newargs = NIL;
ListCell *l;
/* Still at qual top-level */
locContext.isTopQual = context->isTopQual;
foreach(l, ((BoolExpr *) node)->args)
{
Node *newarg;
newarg = process_sublinks_mutator(lfirst(l), &locContext);
if (is_andclause(newarg))
newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
else
newargs = lappend(newargs, newarg);
}
return (Node *) make_andclause(newargs);
}
if (is_orclause(node))
{
List *newargs = NIL;
ListCell *l;
/* Still at qual top-level */
locContext.isTopQual = context->isTopQual;
foreach(l, ((BoolExpr *) node)->args)
{
Node *newarg;
newarg = process_sublinks_mutator(lfirst(l), &locContext);
if (is_orclause(newarg))
newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
else
newargs = lappend(newargs, newarg);
}
return (Node *) make_orclause(newargs);
}
/*
* If we recurse down through anything other than an AND or OR node, we
* are definitely not at top qual level anymore.
*/
locContext.isTopQual = false;
return expression_tree_mutator(node,
process_sublinks_mutator,
(void *) &locContext);
}
/*
* SS_identify_outer_params - identify the Params available from outer levels
*
* This must be run after SS_replace_correlation_vars and SS_process_sublinks
* processing is complete in a given query level as well as all of its
* descendant levels (which means it's most practical to do it at the end of
* processing the query level). We compute the set of paramIds that outer
* levels will make available to this level+descendants, and record it in
* root->outer_params for use while computing extParam/allParam sets in final
* plan cleanup. (We can't just compute it then, because the upper levels'
* plan_params lists are transient and will be gone by then.)
*
* Input:
* root - PlannerInfo structure that is necessary for walking the tree
* Output:
* plan->extParam and plan->allParam - attach params to top of the plan
*/
void
SS_identify_outer_params(PlannerInfo *root)
{
Bitmapset *outer_params;
PlannerInfo *proot;
ListCell *l;
/*
* If no parameters have been assigned anywhere in the tree, we certainly
* don't need to do anything here.
*/
if (root->glob->paramExecTypes == NIL)
return;
/*
* Scan all query levels above this one to see which parameters are due to
* be available from them, either because lower query levels have
* requested them (via plan_params) or because they will be available from
* initPlans of those levels.
*/
outer_params = NULL;
for (proot = root->parent_root; proot != NULL; proot = proot->parent_root)
{
/* Include ordinary Var/PHV/Aggref params */
foreach(l, proot->plan_params)
{
PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
outer_params = bms_add_member(outer_params, pitem->paramId);
}
/* Include any outputs of outer-level initPlans */
foreach(l, proot->init_plans)
{
SubPlan *initsubplan = (SubPlan *) lfirst(l);
ListCell *l2;
foreach(l2, initsubplan->setParam)
{
outer_params = bms_add_member(outer_params, lfirst_int(l2));
}
}
/* Include worktable ID, if a recursive query is being planned */
if (proot->wt_param_id >= 0)
outer_params = bms_add_member(outer_params, proot->wt_param_id);
}
root->outer_params = outer_params;
}
/*
* SS_charge_for_initplans - account for initplans in Path costs & parallelism
*
* If any initPlans have been created in the current query level, they will
* get attached to the Plan tree created from whichever Path we select from
* the given rel. Increment all that rel's Paths' costs to account for them,
* and make sure the paths get marked as parallel-unsafe, since we can't
* currently transmit initPlans to parallel workers.
*
* This is separate from SS_attach_initplans because we might conditionally
* create more initPlans during create_plan(), depending on which Path we
* select. However, Paths that would generate such initPlans are expected
* to have included their cost already.
*/
void
SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
{
Cost initplan_cost;
ListCell *lc;
/* Nothing to do if no initPlans */
if (root->init_plans == NIL)
return;
/*
* Compute the cost increment just once, since it will be the same for all
* Paths. We assume each initPlan gets run once during top plan startup.
* This is a conservative overestimate, since in fact an initPlan might be
* executed later than plan startup, or even not at all.
*/
initplan_cost = 0;
foreach(lc, root->init_plans)
{
SubPlan *initsubplan = (SubPlan *) lfirst(lc);
initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
}
/*
* Now adjust the costs and parallel_safe flags.
*/
foreach(lc, final_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
path->startup_cost += initplan_cost;
path->total_cost += initplan_cost;
path->parallel_safe = false;
}
/*
* Forget about any partial paths and clear consider_parallel, too;
* they're not usable if we attached an initPlan.
*/
final_rel->partial_pathlist = NIL;
final_rel->consider_parallel = false;
/* We needn't do set_cheapest() here, caller will do it */
}
/*
* SS_attach_initplans - attach initplans to topmost plan node
*
* Attach any initplans created in the current query level to the specified
* plan node, which should normally be the topmost node for the query level.
* (In principle the initPlans could go in any node at or above where they're
* referenced; but there seems no reason to put them any lower than the
* topmost node, so we don't bother to track exactly where they came from.)
* We do not touch the plan node's cost; the initplans should have been
* accounted for in path costing.
*/
void
SS_attach_initplans(PlannerInfo *root, Plan *plan)
{
/*
* GPDB: make a copy of the list, because it gets free'd from the plan
* later, in the remove_unused_initplans() step.
*/
plan->initPlan = list_copy(root->init_plans);
}
/*
* SS_finalize_plan - do final parameter processing for a completed Plan.
*
* This recursively computes the extParam and allParam sets for every Plan
* node in the given plan tree. (Oh, and RangeTblFunction.funcparams too.)
*
* We assume that SS_finalize_plan has already been run on any initplans or
* subplans the plan tree could reference.
*/
void
SS_finalize_plan(PlannerInfo *root, Plan *plan)
{
/* No setup needed, just recurse through plan tree. */
(void) finalize_plan(root, plan, -1, root->outer_params, NULL);
}
/*
* Recursive processing of all nodes in the plan tree
*
* gather_param is the rescan_param of an ancestral Gather/GatherMerge,
* or -1 if there is none.
*
* valid_params is the set of param IDs supplied by outer plan levels
* that are valid to reference in this plan node or its children.
*
* scan_params is a set of param IDs to force scan plan nodes to reference.
* This is for EvalPlanQual support, and is always NULL at the top of the
* recursion.
*
* The return value is the computed allParam set for the given Plan node.
* This is just an internal notational convenience: we can add a child
* plan's allParams to the set of param IDs of interest to this level
* in the same statement that recurses to that child.
*
* Do not scribble on caller's values of valid_params or scan_params!
*
* Note: although we attempt to deal with initPlans anywhere in the tree, the
* logic is not really right. The problem is that a plan node might return an
* output Param of its initPlan as a targetlist item, in which case it's valid
* for the parent plan level to reference that same Param; the parent's usage
* will be converted into a Var referencing the child plan node by setrefs.c.
* But this function would see the parent's reference as out of scope and
* complain about it. For now, this does not matter because the planner only
* attaches initPlans to the topmost plan node in a query level, so the case
* doesn't arise. If we ever merge this processing into setrefs.c, maybe it
* can be handled more cleanly.
*/
static Bitmapset *
finalize_plan(PlannerInfo *root, Plan *plan,
int gather_param,
Bitmapset *valid_params,
Bitmapset *scan_params)
{
finalize_primnode_context context;
int locally_added_param;
Bitmapset *nestloop_params;
Bitmapset *initExtParam;
Bitmapset *initSetParam;
Bitmapset *child_params;
ListCell *l;
if (plan == NULL)
return NULL;
context.root = root;
context.paramids = NULL; /* initialize set to empty */
locally_added_param = -1; /* there isn't one */
nestloop_params = NULL; /* there aren't any */
/*
* Examine any initPlans to determine the set of external params they
* reference and the set of output params they supply. (We assume
* SS_finalize_plan was run on them already.)
*/
initExtParam = initSetParam = NULL;
/*
* In gpdb, we traverse init_plans in PlannerInfo to fetch initSetParam fetch.
* In upstream should be `foreach(l, plan->initPlan)`
*
* The different is introduced since sometimes we create a Materized node upon
* subplan, so initPlan info is hidden under Materized Node lefttree.
*/
foreach(l, root->init_plans)
{
SubPlan *initsubplan = (SubPlan *) lfirst(l);
Plan *initplan = planner_subplan_get_plan(root, initsubplan);
ListCell *l2;
initExtParam = bms_add_members(initExtParam, initplan->extParam);
foreach(l2, initsubplan->setParam)
{
initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
}
}
/* Any setParams are validly referenceable in this node and children */
if (initSetParam)
valid_params = bms_union(valid_params, initSetParam);
/*
* When we call finalize_primnode, context.paramids sets are automatically
* merged together. But when recursing to self, we have to do it the hard
* way. We want the paramids set to include params in subplans as well as
* at this level.
*/
/* Find params in targetlist and qual */
finalize_primnode((Node *) plan->targetlist, &context);
finalize_primnode((Node *) plan->qual, &context);
/*
* If it's a parallel-aware scan node, mark it as dependent on the parent
* Gather/GatherMerge's rescan Param.
*/
if (plan->parallel_aware)
{
if (gather_param < 0)
elog(ERROR, "parallel-aware plan node is not below a Gather");
context.paramids =
bms_add_member(context.paramids, gather_param);
}
/* Check additional node-type-specific fields */
switch (nodeTag(plan))
{
case T_Result:
finalize_primnode(((Result *) plan)->resconstantqual,
&context);
break;
case T_SeqScan:
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_SampleScan:
finalize_primnode((Node *) ((SampleScan *) plan)->tablesample,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_IndexScan:
finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
&context);
finalize_primnode((Node *) ((IndexScan *) plan)->indexorderby,
&context);
/*
* we need not look at indexqualorig, since it will have the same
* param references as indexqual. Likewise, we can ignore
* indexorderbyorig.
*/
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_IndexOnlyScan:
finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexqual,
&context);
finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexorderby,
&context);
/*
* we need not look at indextlist, since it cannot contain Params.
*/
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_BitmapIndexScan:
finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
&context);
/*
* we need not look at indexqualorig, since it will have the same
* param references as indexqual.
*/
break;
case T_BitmapHeapScan:
finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_TidScan:
finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_SubqueryScan:
{
SubqueryScan *sscan = (SubqueryScan *) plan;
RelOptInfo *rel;
Bitmapset *subquery_params;
/* We must run finalize_plan on the subquery */
rel = find_base_rel(root, sscan->scan.scanrelid);
subquery_params = rel->subroot->outer_params;
if (gather_param >= 0)
subquery_params = bms_add_member(bms_copy(subquery_params),
gather_param);
finalize_plan(rel->subroot, sscan->subplan, gather_param,
subquery_params, NULL);
/* Now we can add its extParams to the parent's params */
context.paramids = bms_add_members(context.paramids,
sscan->subplan->extParam);
/* We need scan_params too, though */
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_TableFunctionScan:
{
RangeTblEntry *rte;
RangeTblFunction *rtfunc;
rte = rt_fetch(((TableFunctionScan *) plan)->scan.scanrelid,
root->parse->rtable);
Assert(rte->rtekind == RTE_TABLEFUNCTION);
Assert(list_length(rte->functions) == 1);
rtfunc = (RangeTblFunction *) linitial(rte->functions);
finalize_primnode(rtfunc->funcexpr, &context);
/*
* GPDB_94_MERGE_FIXME: should we do something about params in
* the function expressions, like for FunctionScan nodes below?
*/
}
/* TableFunctionScan's lefttree is like SubqueryScan's subplan. */
context.paramids = bms_add_members(context.paramids,
plan->lefttree->extParam);
break;
case T_FunctionScan:
{
FunctionScan *fscan = (FunctionScan *) plan;
ListCell *lc;
/*
* Call finalize_primnode independently on each function
* expression, so that we can record which params are
* referenced in each, in order to decide which need
* re-evaluating during rescan.
*/
foreach(lc, fscan->functions)
{
RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
finalize_primnode_context funccontext;
funccontext = context;
funccontext.paramids = NULL;
finalize_primnode(rtfunc->funcexpr, &funccontext);
/* remember results for execution */
rtfunc->funcparams = funccontext.paramids;
/* add the function's params to the overall set */
context.paramids = bms_add_members(context.paramids,
funccontext.paramids);
}
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_TableFuncScan:
finalize_primnode((Node *) ((TableFuncScan *) plan)->tablefunc,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_ValuesScan:
finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_CteScan:
{
/*
* You might think we should add the node's cteParam to
* paramids, but we shouldn't because that param is just a
* linkage mechanism for multiple CteScan nodes for the same
* CTE; it is never used for changed-param signaling. What we
* have to do instead is to find the referenced CTE plan and
* incorporate its external paramids, so that the correct
* things will happen if the CTE references outer-level
* variables. See test cases for bug #4902. (We assume
* SS_finalize_plan was run on the CTE plan already.)
*/
int plan_id = ((CteScan *) plan)->ctePlanId;
Plan *cteplan;
/* so, do this ... */
if (plan_id < 1 || plan_id > list_length(root->glob->subplans))
elog(ERROR, "could not find plan for CteScan referencing plan ID %d",
plan_id);
cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
context.paramids =
bms_add_members(context.paramids, cteplan->extParam);
#ifdef NOT_USED
/* ... but not this */
context.paramids =
bms_add_member(context.paramids,
((CteScan *) plan)->cteParam);
#endif
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_WorkTableScan:
context.paramids =
bms_add_member(context.paramids,
((WorkTableScan *) plan)->wtParam);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_NamedTuplestoreScan:
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_ForeignScan:
{
ForeignScan *fscan = (ForeignScan *) plan;
finalize_primnode((Node *) fscan->fdw_exprs,
&context);
finalize_primnode((Node *) fscan->fdw_recheck_quals,
&context);
/* We assume fdw_scan_tlist cannot contain Params */
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_CustomScan:
{
CustomScan *cscan = (CustomScan *) plan;
ListCell *lc;
finalize_primnode((Node *) cscan->custom_exprs,
&context);
/* We assume custom_scan_tlist cannot contain Params */
context.paramids =
bms_add_members(context.paramids, scan_params);
/* child nodes if any */
foreach(lc, cscan->custom_plans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(lc),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_ModifyTable:
{
ModifyTable *mtplan = (ModifyTable *) plan;
ListCell *l;
/* Force descendant scan nodes to reference epqParam */
locally_added_param = mtplan->epqParam;
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
scan_params = bms_add_member(bms_copy(scan_params),
locally_added_param);
finalize_primnode((Node *) mtplan->returningLists,
&context);
finalize_primnode((Node *) mtplan->onConflictSet,
&context);
finalize_primnode((Node *) mtplan->onConflictWhere,
&context);
/* exclRelTlist contains only Vars, doesn't need examination */
foreach(l, mtplan->plans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_Append:
{
ListCell *l;
foreach(l, ((Append *) plan)->appendplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_MergeAppend:
{
ListCell *l;
foreach(l, ((MergeAppend *) plan)->mergeplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_BitmapAnd:
{
ListCell *l;
foreach(l, ((BitmapAnd *) plan)->bitmapplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_BitmapOr:
{
ListCell *l;
foreach(l, ((BitmapOr *) plan)->bitmapplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_NestLoop:
{
ListCell *l;
finalize_primnode((Node *) ((Join *) plan)->joinqual,
&context);
/* collect set of params that will be passed to right child */
foreach(l, ((NestLoop *) plan)->nestParams)
{
NestLoopParam *nlp = (NestLoopParam *) lfirst(l);
nestloop_params = bms_add_member(nestloop_params,
nlp->paramno);
}
}
break;
case T_MergeJoin:
finalize_primnode((Node *) ((Join *) plan)->joinqual,
&context);
finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
&context);
break;
case T_HashJoin:
finalize_primnode((Node *) ((Join *) plan)->joinqual,
&context);
finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
&context);
finalize_primnode((Node *) ((HashJoin *) plan)->hashqualclauses,
&context);
break;
case T_Motion:
finalize_primnode((Node *) ((Motion *) plan)->hashExprs,
&context);
break;
case T_Limit:
finalize_primnode(((Limit *) plan)->limitOffset,
&context);
finalize_primnode(((Limit *) plan)->limitCount,
&context);
break;
case T_PartitionSelector:
/* the paramid in PartitionSelector struct is a special executor param
* which is used to do partition pruning in an Append node on the other
* side of the join. It can also contain normal executor params in
* part_prune_info field.
* But all of the params above are only used to compute which partitions
* on other side of a join can contain rows that match the join quals.
* The tuple from the child plan will pass to the outerplan node directly
* after the computation. So the params above won't affect the output of
* this plan node.
* The params in part_prune_info field still can affect the result of the
* outer join, but the params in part_prune_info are also in join qual or
* join filter of outer join node, so that these params will be added to
* outer join plan's extParam and allParam whatever.
* And PartitionSelector node don't support rescan for now, as the above,
* don't add the paramids here won't affect the execute result.
*/
break;
case T_RecursiveUnion:
/* child nodes are allowed to reference wtParam */
locally_added_param = ((RecursiveUnion *) plan)->wtParam;
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
/* wtParam does *not* get added to scan_params */
break;
case T_LockRows:
/* Force descendant scan nodes to reference epqParam */
locally_added_param = ((LockRows *) plan)->epqParam;
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
scan_params = bms_add_member(bms_copy(scan_params),
locally_added_param);
break;
case T_Agg:
{
Agg *agg = (Agg *) plan;
/*
* AGG_HASHED plans need to know which Params are referenced
* in aggregate calls. Do a separate scan to identify them.
*/
if (agg->aggstrategy == AGG_HASHED)
{
finalize_primnode_context aggcontext;
aggcontext.root = root;
aggcontext.paramids = NULL;
finalize_agg_primnode((Node *) agg->plan.targetlist,
&aggcontext);
finalize_agg_primnode((Node *) agg->plan.qual,
&aggcontext);
agg->aggParams = aggcontext.paramids;
}
}
break;
case T_WindowAgg:
finalize_primnode(((WindowAgg *) plan)->startOffset,
&context);
finalize_primnode(((WindowAgg *) plan)->endOffset,
&context);
break;
case T_Gather:
/* child nodes are allowed to reference rescan_param, if any */
locally_added_param = ((Gather *) plan)->rescan_param;
if (locally_added_param >= 0)
{
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
/*
* We currently don't support nested Gathers. The issue so
* far as this function is concerned would be how to identify
* which child nodes depend on which Gather.
*/
Assert(gather_param < 0);
/* Pass down rescan_param to child parallel-aware nodes */
gather_param = locally_added_param;
}
/* rescan_param does *not* get added to scan_params */
break;
case T_GatherMerge:
/* child nodes are allowed to reference rescan_param, if any */
locally_added_param = ((GatherMerge *) plan)->rescan_param;
if (locally_added_param >= 0)
{
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
/*
* We currently don't support nested Gathers. The issue so
* far as this function is concerned would be how to identify
* which child nodes depend on which Gather.
*/
Assert(gather_param < 0);
/* Pass down rescan_param to child parallel-aware nodes */
gather_param = locally_added_param;
}
/* rescan_param does *not* get added to scan_params */
break;
case T_ProjectSet:
case T_Hash:
case T_Material:
case T_Sort:
case T_ShareInputScan:
case T_Unique:
case T_SetOp:
case T_SplitUpdate:
case T_TupleSplit:
/* no node-type-specific fields need fixing */
break;
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(plan));
}
/* Process left and right child plans, if any */
/*
* In a TableFunctionScan, the 'lefttree' is more like a SubQueryScan's
* subplan, and contains a plan that's already been finalized by the
* inner invocation of subquery_planner(). So skip that.
*/
if (!IsA(plan, TableFunctionScan))
{
child_params = finalize_plan(root,
plan->lefttree,
gather_param,
valid_params,
scan_params);
context.paramids = bms_add_members(context.paramids, child_params);
}
if (nestloop_params)
{
/* right child can reference nestloop_params as well as valid_params */
child_params = finalize_plan(root,
plan->righttree,
gather_param,
bms_union(nestloop_params, valid_params),
scan_params);
/* ... and they don't count as parameters used at my level */
child_params = bms_difference(child_params, nestloop_params);
bms_free(nestloop_params);
}
else
{
/* easy case */
child_params = finalize_plan(root,
plan->righttree,
gather_param,
valid_params,
scan_params);
}
context.paramids = bms_add_members(context.paramids, child_params);
/*
* Any locally generated parameter doesn't count towards its generating
* plan node's external dependencies. (Note: if we changed valid_params
* and/or scan_params, we leak those bitmapsets; not worth the notational
* trouble to clean them up.)
*/
if (locally_added_param >= 0)
{
context.paramids = bms_del_member(context.paramids,
locally_added_param);
}
/* Now we have all the paramids referenced in this node and children */
if (!bms_is_subset(context.paramids, valid_params))
elog(ERROR, "plan should not reference subplan's variable");
/*
* The plan node's allParam and extParam fields should include all its
* referenced paramids, plus contributions from any child initPlans.
* However, any setParams of the initPlans should not be present in the
* parent node's extParams, only in its allParams. (It's possible that
* some initPlans have extParams that are setParams of other initPlans.)
*/
/* allParam must include initplans' extParams and setParams */
plan->allParam = bms_union(context.paramids, initExtParam);
plan->allParam = bms_add_members(plan->allParam, initSetParam);
/* extParam must include any initplan extParams */
plan->extParam = bms_union(context.paramids, initExtParam);
/* but not any initplan setParams */
plan->extParam = bms_del_members(plan->extParam, initSetParam);
/*
* Currently GPDB doesn't fully support shareinputscan referencing outer
* rels.
*/
if (IsA(plan, ShareInputScan) && !bms_is_empty(plan->extParam))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("shareinputscan with outer refs is not supported by GPDB")));
/*
* For speed at execution time, make sure extParam/allParam are actually
* NULL if they are empty sets.
*/
if (bms_is_empty(plan->extParam))
plan->extParam = NULL;
if (bms_is_empty(plan->allParam))
plan->allParam = NULL;
return plan->allParam;
}
/*
* finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
* expression tree to the result set.
*/
static bool
finalize_primnode(Node *node, finalize_primnode_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Param))
{
if (((Param *) node)->paramkind == PARAM_EXEC)
{
int paramid = ((Param *) node)->paramid;
context->paramids = bms_add_member(context->paramids, paramid);
}
return false; /* no more to do here */
}
if (IsA(node, SubPlan))
{
SubPlan *subplan = (SubPlan *) node;
Plan *plan = planner_subplan_get_plan(context->root, subplan);
ListCell *lc;
Bitmapset *subparamids;
/* Recurse into the testexpr, but not into the Plan */
finalize_primnode(subplan->testexpr, context);
/*
* Remove any param IDs of output parameters of the subplan that were
* referenced in the testexpr. These are not interesting for
* parameter change signaling since we always re-evaluate the subplan.
* Note that this wouldn't work too well if there might be uses of the
* same param IDs elsewhere in the plan, but that can't happen because
* generate_new_exec_param never tries to merge params.
*/
foreach(lc, subplan->paramIds)
{
context->paramids = bms_del_member(context->paramids,
lfirst_int(lc));
}
/* Also examine args list */
finalize_primnode((Node *) subplan->args, context);
/*
* Add params needed by the subplan to paramids, but excluding those
* we will pass down to it. (We assume SS_finalize_plan was run on
* the subplan already.)
*/
subparamids = bms_copy(plan->extParam);
foreach(lc, subplan->parParam)
{
subparamids = bms_del_member(subparamids, lfirst_int(lc));
}
context->paramids = bms_join(context->paramids, subparamids);
return false; /* no more to do here */
}
return expression_tree_walker(node, finalize_primnode,
(void *) context);
}
/*
* finalize_agg_primnode: find all Aggref nodes in the given expression tree,
* and add IDs of all PARAM_EXEC params appearing within their aggregated
* arguments to the result set.
*/
static bool
finalize_agg_primnode(Node *node, finalize_primnode_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Aggref))
{
Aggref *agg = (Aggref *) node;
/* we should not consider the direct arguments, if any */
finalize_primnode((Node *) agg->args, context);
finalize_primnode((Node *) agg->aggfilter, context);
return false; /* there can't be any Aggrefs below here */
}
return expression_tree_walker(node, finalize_agg_primnode,
(void *) context);
}
/*
* SS_make_initplan_output_param - make a Param for an initPlan's output
*
* The plan is expected to return a scalar value of the given type/collation.
*
* Note that in some cases the initplan may not ever appear in the finished
* plan tree. If that happens, we'll have wasted a PARAM_EXEC slot, which
* is no big deal.
*/
Param *
SS_make_initplan_output_param(PlannerInfo *root,
Oid resulttype, int32 resulttypmod,
Oid resultcollation)
{
return generate_new_exec_param(root, resulttype,
resulttypmod, resultcollation);
}
/*
* SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
*
* We build an EXPR_SUBLINK SubPlan node and put it into the initplan
* list for the outer query level. A Param that represents the initplan's
* output has already been assigned using SS_make_initplan_output_param.
*
* We treat root->init_plans like the old PlannerInitPlan global here.
*/
void
SS_make_initplan_from_plan(PlannerInfo *root,
PlannerInfo *subroot, Plan *plan,
PlanSlice *subslice,
Param *prm, bool is_initplan_func_sublink)
{
SubPlan *node;
/*
* Add the subplan and its PlannerInfo to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, plan);
root->glob->subroots = lappend(root->glob->subroots, subroot);
/*
* Create a SubPlan node and add it to the outer list of InitPlans. Note
* it has to appear after any other InitPlans it might depend on (see
* comments in ExecReScan).
*/
node = makeNode(SubPlan);
if (is_initplan_func_sublink)
node->subLinkType = INITPLAN_FUNC_SUBLINK;
else
node->subLinkType = EXPR_SUBLINK;
node->plan_id = list_length(root->glob->subplans);
node->plan_name = psprintf("InitPlan %d (returns $%d)",
node->plan_id, prm->paramid);
get_first_col_type(plan, &node->firstColType, &node->firstColTypmod,
&node->firstColCollation);
node->is_initplan = true;
node->setParam = list_make1_int(prm->paramid);
root->init_plans = lappend(root->init_plans, node);
/*
* The node can't have any inputs (since it's an initplan), so the
* parParam and args lists remain empty.
*/
/* NB PostgreSQL calculates subplan cost here, but GPDB does it elsewhere. */
}
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