greenplumn partcache 源码
greenplumn partcache 代码
文件路径：/src/backend/utils/cache/partcache.c
/*-------------------------------------------------------------------------
*
* partcache.c
* Support routines for manipulating partition information cached in
* relcache
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/cache/partcache.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/hash.h"
#include "access/htup_details.h"
#include "access/nbtree.h"
#include "access/relation.h"
#include "catalog/partition.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_partitioned_table.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "partitioning/partbounds.h"
#include "rewrite/rewriteHandler.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/partcache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
static List *generate_partition_qual(Relation rel);
/*
* RelationBuildPartitionKey
* Build partition key data of relation, and attach to relcache
*
* Partitioning key data is a complex structure; to avoid complicated logic to
* free individual elements whenever the relcache entry is flushed, we give it
* its own memory context, a child of CacheMemoryContext, which can easily be
* deleted on its own. To avoid leaking memory in that context in case of an
* error partway through this function, the context is initially created as a
* child of CurTransactionContext and only re-parented to CacheMemoryContext
* at the end, when no further errors are possible. Also, we don't make this
* context the current context except in very brief code sections, out of fear
* that some of our callees allocate memory on their own which would be leaked
* permanently.
*/
void
RelationBuildPartitionKey(Relation relation)
{
Form_pg_partitioned_table form;
HeapTuple tuple;
bool isnull;
int i;
PartitionKey key;
AttrNumber *attrs;
oidvector *opclass;
oidvector *collation;
ListCell *partexprs_item;
Datum datum;
MemoryContext partkeycxt,
oldcxt;
int16 procnum;
tuple = SearchSysCache1(PARTRELID,
ObjectIdGetDatum(RelationGetRelid(relation)));
/*
* The following happens when we have created our pg_class entry but not
* the pg_partitioned_table entry yet.
*/
if (!HeapTupleIsValid(tuple))
return;
partkeycxt = AllocSetContextCreate(CurTransactionContext,
"partition key",
ALLOCSET_SMALL_SIZES);
MemoryContextCopyAndSetIdentifier(partkeycxt,
RelationGetRelationName(relation));
key = (PartitionKey) MemoryContextAllocZero(partkeycxt,
sizeof(PartitionKeyData));
/* Fixed-length attributes */
form = (Form_pg_partitioned_table) GETSTRUCT(tuple);
key->strategy = form->partstrat;
key->partnatts = form->partnatts;
/*
* We can rely on the first variable-length attribute being mapped to the
* relevant field of the catalog's C struct, because all previous
* attributes are non-nullable and fixed-length.
*/
attrs = form->partattrs.values;
/* But use the hard way to retrieve further variable-length attributes */
/* Operator class */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partclass, &isnull);
Assert(!isnull);
opclass = (oidvector *) DatumGetPointer(datum);
/* Collation */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partcollation, &isnull);
Assert(!isnull);
collation = (oidvector *) DatumGetPointer(datum);
/* Expressions */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partexprs, &isnull);
if (!isnull)
{
char *exprString;
Node *expr;
exprString = TextDatumGetCString(datum);
expr = stringToNode(exprString);
pfree(exprString);
/*
* Run the expressions through const-simplification since the planner
* will be comparing them to similarly-processed qual clause operands,
* and may fail to detect valid matches without this step; fix
* opfuncids while at it. We don't need to bother with
* canonicalize_qual() though, because partition expressions should be
* in canonical form already (ie, no need for OR-merging or constant
* elimination).
*/
expr = eval_const_expressions(NULL, expr);
fix_opfuncids(expr);
oldcxt = MemoryContextSwitchTo(partkeycxt);
key->partexprs = (List *) copyObject(expr);
MemoryContextSwitchTo(oldcxt);
}
/* Allocate assorted arrays in the partkeycxt, which we'll fill below */
oldcxt = MemoryContextSwitchTo(partkeycxt);
key->partattrs = (AttrNumber *) palloc0(key->partnatts * sizeof(AttrNumber));
key->partopfamily = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->partopcintype = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->partsupfunc = (FmgrInfo *) palloc0(key->partnatts * sizeof(FmgrInfo));
key->partcollation = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->parttypid = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->parttypmod = (int32 *) palloc0(key->partnatts * sizeof(int32));
key->parttyplen = (int16 *) palloc0(key->partnatts * sizeof(int16));
key->parttypbyval = (bool *) palloc0(key->partnatts * sizeof(bool));
key->parttypalign = (char *) palloc0(key->partnatts * sizeof(char));
key->parttypcoll = (Oid *) palloc0(key->partnatts * sizeof(Oid));
MemoryContextSwitchTo(oldcxt);
/* determine support function number to search for */
procnum = (key->strategy == PARTITION_STRATEGY_HASH) ?
HASHEXTENDED_PROC : BTORDER_PROC;
/* Copy partattrs and fill other per-attribute info */
memcpy(key->partattrs, attrs, key->partnatts * sizeof(int16));
partexprs_item = list_head(key->partexprs);
for (i = 0; i < key->partnatts; i++)
{
AttrNumber attno = key->partattrs[i];
HeapTuple opclasstup;
Form_pg_opclass opclassform;
Oid funcid;
/* Collect opfamily information */
opclasstup = SearchSysCache1(CLAOID,
ObjectIdGetDatum(opclass->values[i]));
if (!HeapTupleIsValid(opclasstup))
elog(ERROR, "cache lookup failed for opclass %u", opclass->values[i]);
opclassform = (Form_pg_opclass) GETSTRUCT(opclasstup);
key->partopfamily[i] = opclassform->opcfamily;
key->partopcintype[i] = opclassform->opcintype;
/* Get a support function for the specified opfamily and datatypes */
funcid = get_opfamily_proc(opclassform->opcfamily,
opclassform->opcintype,
opclassform->opcintype,
procnum);
if (!OidIsValid(funcid))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("operator class \"%s\" of access method %s is missing support function %d for type %s",
NameStr(opclassform->opcname),
(key->strategy == PARTITION_STRATEGY_HASH) ?
"hash" : "btree",
procnum,
format_type_be(opclassform->opcintype))));
fmgr_info_cxt(funcid, &key->partsupfunc[i], partkeycxt);
/* Collation */
key->partcollation[i] = collation->values[i];
/* Collect type information */
if (attno != 0)
{
Form_pg_attribute att = TupleDescAttr(relation->rd_att, attno - 1);
key->parttypid[i] = att->atttypid;
key->parttypmod[i] = att->atttypmod;
key->parttypcoll[i] = att->attcollation;
}
else
{
if (partexprs_item == NULL)
elog(ERROR, "wrong number of partition key expressions");
key->parttypid[i] = exprType(lfirst(partexprs_item));
key->parttypmod[i] = exprTypmod(lfirst(partexprs_item));
key->parttypcoll[i] = exprCollation(lfirst(partexprs_item));
partexprs_item = lnext(partexprs_item);
}
get_typlenbyvalalign(key->parttypid[i],
&key->parttyplen[i],
&key->parttypbyval[i],
&key->parttypalign[i]);
ReleaseSysCache(opclasstup);
}
ReleaseSysCache(tuple);
/* Assert that we're not leaking any old data during assignments below */
Assert(relation->rd_partkeycxt == NULL);
Assert(relation->rd_partkey == NULL);
/*
* Success --- reparent our context and make the relcache point to the
* newly constructed key
*/
MemoryContextSetParent(partkeycxt, CacheMemoryContext);
relation->rd_partkeycxt = partkeycxt;
relation->rd_partkey = key;
}
/*
* RelationGetPartitionQual
*
* Returns a list of partition quals
*/
List *
RelationGetPartitionQual(Relation rel)
{
/* Quick exit */
if (!rel->rd_rel->relispartition)
return NIL;
return generate_partition_qual(rel);
}
/*
* get_partition_qual_relid
*
* Returns an expression tree describing the passed-in relation's partition
* constraint.
*
* If the relation is not found, or is not a partition, or there is no
* partition constraint, return NULL. We must guard against the first two
* cases because this supports a SQL function that could be passed any OID.
* The last case can happen even if relispartition is true, when a default
* partition is the only partition.
*/
Expr *
get_partition_qual_relid(Oid relid)
{
Expr *result = NULL;
/* Do the work only if this relation exists and is a partition. */
if (get_rel_relispartition(relid))
{
Relation rel = relation_open(relid, AccessShareLock);
List *and_args;
and_args = generate_partition_qual(rel);
/* Convert implicit-AND list format to boolean expression */
if (and_args == NIL)
result = NULL;
else if (list_length(and_args) > 1)
result = makeBoolExpr(AND_EXPR, and_args, -1);
else
result = linitial(and_args);
/* Keep the lock, to allow safe deparsing against the rel by caller. */
relation_close(rel, NoLock);
}
return result;
}
/*
* generate_partition_qual
*
* Generate partition predicate from rel's partition bound expression. The
* function returns a NIL list if there is no predicate.
*
* We cache a copy of the result in the relcache entry, after constructing
* it using the caller's context. This approach avoids leaking any data
* into long-lived cache contexts, especially if we fail partway through.
*/
static List *
generate_partition_qual(Relation rel)
{
HeapTuple tuple;
MemoryContext oldcxt;
Datum boundDatum;
bool isnull;
List *my_qual = NIL,
*result = NIL;
Relation parent;
bool found_whole_row;
/* Guard against stack overflow due to overly deep partition tree */
check_stack_depth();
/* If we already cached the result, just return a copy */
if (rel->rd_partcheckvalid)
return copyObject(rel->rd_partcheck);
/* Grab at least an AccessShareLock on the parent table */
parent = relation_open(get_partition_parent(RelationGetRelid(rel)),
AccessShareLock);
/* Get pg_class.relpartbound */
tuple = SearchSysCache1(RELOID, RelationGetRelid(rel));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
boundDatum = SysCacheGetAttr(RELOID, tuple,
Anum_pg_class_relpartbound,
&isnull);
if (!isnull)
{
PartitionBoundSpec *bound;
bound = castNode(PartitionBoundSpec,
stringToNode(TextDatumGetCString(boundDatum)));
my_qual = get_qual_from_partbound(rel, parent, bound);
}
ReleaseSysCache(tuple);
/* Add the parent's quals to the list (if any) */
if (parent->rd_rel->relispartition)
result = list_concat(generate_partition_qual(parent), my_qual);
else
result = my_qual;
/*
* Change Vars to have partition's attnos instead of the parent's. We do
* this after we concatenate the parent's quals, because we want every Var
* in it to bear this relation's attnos. It's safe to assume varno = 1
* here.
*/
result = map_partition_varattnos(result, 1, rel, parent,
&found_whole_row);
/* There can never be a whole-row reference here */
if (found_whole_row)
elog(ERROR, "unexpected whole-row reference found in partition key");
/* Assert that we're not leaking any old data during assignments below */
Assert(rel->rd_partcheckcxt == NULL);
Assert(rel->rd_partcheck == NIL);
/*
* Save a copy in the relcache. The order of these operations is fairly
* critical to avoid memory leaks and ensure that we don't leave a corrupt
* relcache entry if we fail partway through copyObject.
*
* If, as is definitely possible, the partcheck list is NIL, then we do
* not need to make a context to hold it.
*/
if (result != NIL)
{
rel->rd_partcheckcxt = AllocSetContextCreate(CacheMemoryContext,
"partition constraint",
ALLOCSET_SMALL_SIZES);
MemoryContextCopyAndSetIdentifier(rel->rd_partcheckcxt,
RelationGetRelationName(rel));
oldcxt = MemoryContextSwitchTo(rel->rd_partcheckcxt);
rel->rd_partcheck = copyObject(result);
MemoryContextSwitchTo(oldcxt);
}
else
rel->rd_partcheck = NIL;
rel->rd_partcheckvalid = true;
/* Keep the parent locked until commit */
relation_close(parent, NoLock);
/* Return the working copy to the caller */
return result;
}
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