Reorganize partitioning code

There's been a massive addition of partitioning code in PostgreSQL 11,
with little oversight on its placement, resulting in a
catalog/partition.c with poorly defined boundaries and responsibilities.
This commit tries to set a couple of distinct modules to separate things
a little bit.  There are no code changes here, only code movement.

There are three new files:
  src/backend/utils/cache/partcache.c
  src/include/partitioning/partdefs.h
  src/include/utils/partcache.h

The previous arrangement of #including catalog/partition.h almost
everywhere is no more.

Authors: Amit Langote and Álvaro Herrera
Discussion: https://postgr.es/m/98e8d509-790a-128c-be7f-e48a5b2d8d97@lab.ntt.co.jp
	https://postgr.es/m/11aa0c50-316b-18bb-722d-c23814f39059@lab.ntt.co.jp
	https://postgr.es/m/143ed9a4-6038-76d4-9a55-502035815e68@lab.ntt.co.jp
	https://postgr.es/m/20180413193503.nynq7bnmgh6vs5vm@alvherre.pgsql

1 files changed, 2 insertions, 206 deletions

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index dfa95fed300..22ff36714ca 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -73,6 +73,7 @@
 #include "optimizer/cost.h"
 #include "optimizer/prep.h"
 #include "optimizer/var.h"
+#include "partitioning/partbounds.h"
 #include "pgstat.h"
 #include "rewrite/rewriteDefine.h"
 #include "rewrite/rowsecurity.h"
@@ -85,6 +86,7 @@
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/partcache.h"
 #include "utils/relmapper.h"
 #include "utils/resowner_private.h"
 #include "utils/snapmgr.h"
@@ -265,7 +267,6 @@ static HeapTuple ScanPgRelation(Oid targetRelId, bool indexOK, bool force_non_hi
 static Relation AllocateRelationDesc(Form_pg_class relp);
 static void RelationParseRelOptions(Relation relation, HeapTuple tuple);
 static void RelationBuildTupleDesc(Relation relation);
-static void RelationBuildPartitionKey(Relation relation);
 static Relation RelationBuildDesc(Oid targetRelId, bool insertIt);
 static void RelationInitPhysicalAddr(Relation relation);
 static void load_critical_index(Oid indexoid, Oid heapoid);
@@ -874,211 +875,6 @@ RelationBuildRuleLock(Relation relation)
 }
 
 /*
- * RelationBuildPartitionKey
- *		Build and attach to relcache partition key data of relation
- *
- * 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, 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)));
-
-	/*
-	 * 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);
-	}
-
-	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));
-
-	/* Gather type and collation info as well */
-	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);
-
-	/*
-	 * 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;
-}
-
-/*
  *		equalRuleLocks
  *
  *		Determine whether two RuleLocks are equivalent