Adding upstream version 15.5.upstream/15.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 430 insertions, 0 deletions

diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
new file mode 100644
index 0000000..afa99c5
--- /dev/null
+++ b/src/backend/utils/cache/partcache.c
@@ -0,0 +1,430 @@
+/*-------------------------------------------------------------------------
+ *
+ * partcache.c
+ *		Support routines for manipulating partition information cached in
+ *		relcache
+ *
+ * Portions Copyright (c) 1996-2022, 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 void RelationBuildPartitionKey(Relation relation);
+static List *generate_partition_qual(Relation rel);
+
+/*
+ * RelationGetPartitionKey -- get partition key, if relation is partitioned
+ *
+ * Note: partition keys are not allowed to change after the partitioned rel
+ * is created.  RelationClearRelation knows this and preserves rd_partkey
+ * across relcache rebuilds, as long as the relation is open.  Therefore,
+ * even though we hand back a direct pointer into the relcache entry, it's
+ * safe for callers to continue to use that pointer as long as they hold
+ * the relation open.
+ */
+PartitionKey
+RelationGetPartitionKey(Relation rel)
+{
+	if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		return NULL;
+
+	if (unlikely(rel->rd_partkey == NULL))
+		RelationBuildPartitionKey(rel);
+
+	return rel->rd_partkey;
+}
+
+/*
+ * 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.
+ */
+static 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)));
+
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cache lookup failed for partition key of relation %u",
+			 RelationGetRelid(relation));
+
+	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(key->partexprs, 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;
+	Oid			parentrelid;
+	Relation	parent;
+
+	/* 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.  Must do this
+	 * even if the partition has been partially detached, because transactions
+	 * concurrent with the detach might still be trying to use a partition
+	 * descriptor that includes it.
+	 */
+	parentrelid = get_partition_parent(RelationGetRelid(rel), true);
+	parent = relation_open(parentrelid, 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(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);
+
+	/* 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;
+}