Remove a couple of unnecessary calls of CreateCacheMemoryContext. These

probably got there via blind copy-and-paste from one of the legitimate
callers, so rearrange and comment that code a bit to make it clearer that
this isn't a necessary prerequisite to hash_create.  Per observation
from Robert Haas.

src/backend/optimizer/util/predtest.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/predtest.c,v 1.27 2009/06/11 14:48:59 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/predtest.c,v 1.28 2009/12/27 18:55:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1532,9 +1532,6 @@ get_btree_test_op(Oid pred_op, Oid clause_op, bool refute_it)
 		/* First time through: initialize the hash table */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = sizeof(OprProofCacheKey);
 		ctl.entrysize = sizeof(OprProofCacheEntry);

src/backend/parser/parse_oper.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_oper.c,v 1.109 2009/06/13 15:42:09 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_oper.c,v 1.110 2009/12/27 18:55:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1098,9 +1098,6 @@ find_oper_cache_entry(OprCacheKey *key)
 		/* First time through: initialize the hash table */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = sizeof(OprCacheKey);
 		ctl.entrysize = sizeof(OprCacheEntry);

src/backend/utils/cache/relcache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.293 2009/12/07 05:22:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.294 2009/12/27 18:55:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1181,15 +1181,16 @@ LookupOpclassInfo(Oid operatorClassOid,
 		/* First time through: initialize the opclass cache */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = sizeof(Oid);
 		ctl.entrysize = sizeof(OpClassCacheEnt);
 		ctl.hash = oid_hash;
 		OpClassCache = hash_create("Operator class cache", 64,
 								   &ctl, HASH_ELEM | HASH_FUNCTION);
+
+		/* Also make sure CacheMemoryContext exists */
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
 	}
 
 	opcentry = (OpClassCacheEnt *) hash_search(OpClassCache,
@@ -2513,17 +2514,14 @@ RelationBuildLocalRelation(const char *relname,
 void
 RelationCacheInitialize(void)
 {
-	MemoryContext oldcxt;
 	HASHCTL		ctl;
 
 	/*
-	 * switch to cache memory context
+	 * make sure cache memory context exists
 	 */
 	if (!CacheMemoryContext)
 		CreateCacheMemoryContext();
 
-	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
-
 	/*
 	 * create hashtable that indexes the relcache
 	 */
@@ -2533,8 +2531,6 @@ RelationCacheInitialize(void)
 	ctl.hash = oid_hash;
 	RelationIdCache = hash_create("Relcache by OID", INITRELCACHESIZE,
 								  &ctl, HASH_ELEM | HASH_FUNCTION);
-
-	MemoryContextSwitchTo(oldcxt);
 }
 
 /*

src/backend/utils/cache/ts_cache.c

@@ -20,7 +20,7 @@
  * Copyright (c) 2006-2009, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/ts_cache.c,v 1.9 2009/01/01 17:23:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/ts_cache.c,v 1.10 2009/12/27 18:55:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,7 +42,6 @@
 #include "tsearch/ts_cache.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
-#include "utils/catcache.h"
 #include "utils/fmgroids.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -119,9 +118,6 @@ lookup_ts_parser_cache(Oid prsId)
 		/* First time through: initialize the hash table */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = sizeof(Oid);
 		ctl.entrysize = sizeof(TSParserCacheEntry);
@@ -131,6 +127,10 @@ lookup_ts_parser_cache(Oid prsId)
 		/* Flush cache on pg_ts_parser changes */
 		CacheRegisterSyscacheCallback(TSPARSEROID, InvalidateTSCacheCallBack,
 									  PointerGetDatum(TSParserCacheHash));
+
+		/* Also make sure CacheMemoryContext exists */
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
 	}
 
 	/* Check single-entry cache */
@@ -219,9 +219,6 @@ lookup_ts_dictionary_cache(Oid dictId)
 		/* First time through: initialize the hash table */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = sizeof(Oid);
 		ctl.entrysize = sizeof(TSDictionaryCacheEntry);
@@ -233,6 +230,10 @@ lookup_ts_dictionary_cache(Oid dictId)
 									  PointerGetDatum(TSDictionaryCacheHash));
 		CacheRegisterSyscacheCallback(TSTEMPLATEOID, InvalidateTSCacheCallBack,
 									  PointerGetDatum(TSDictionaryCacheHash));
+
+		/* Also make sure CacheMemoryContext exists */
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
 	}
 
 	/* Check single-entry cache */
@@ -370,9 +371,6 @@ init_ts_config_cache(void)
 {
 	HASHCTL		ctl;
 
-	if (!CacheMemoryContext)
-		CreateCacheMemoryContext();
-
 	MemSet(&ctl, 0, sizeof(ctl));
 	ctl.keysize = sizeof(Oid);
 	ctl.entrysize = sizeof(TSConfigCacheEntry);
@@ -384,6 +382,10 @@ init_ts_config_cache(void)
 								  PointerGetDatum(TSConfigCacheHash));
 	CacheRegisterSyscacheCallback(TSCONFIGMAP, InvalidateTSCacheCallBack,
 								  PointerGetDatum(TSConfigCacheHash));
+
+	/* Also make sure CacheMemoryContext exists */
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
 }
 
 /*

src/backend/utils/cache/typcache.c

@@ -36,7 +36,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/typcache.c,v 1.29 2009/01/01 17:23:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/typcache.c,v 1.30 2009/12/27 18:55:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -109,15 +109,16 @@ lookup_type_cache(Oid type_id, int flags)
 		/* First time through: initialize the hash table */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = sizeof(Oid);
 		ctl.entrysize = sizeof(TypeCacheEntry);
 		ctl.hash = oid_hash;
 		TypeCacheHash = hash_create("Type information cache", 64,
 									&ctl, HASH_ELEM | HASH_FUNCTION);
+
+		/* Also make sure CacheMemoryContext exists */
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
 	}
 
 	/* Try to look up an existing entry */
@@ -249,8 +250,8 @@ lookup_type_cache(Oid type_id, int flags)
 	 * Set up fmgr lookup info as requested
 	 *
 	 * Note: we tell fmgr the finfo structures live in CacheMemoryContext,
-	 * which is not quite right (they're really in DynaHashContext) but this
-	 * will do for our purposes.
+	 * which is not quite right (they're really in the hash table's private
+	 * memory context) but this will do for our purposes.
 	 */
 	if ((flags & TYPECACHE_EQ_OPR_FINFO) &&
 		typentry->eq_opr_finfo.fn_oid == InvalidOid &&
@@ -424,15 +425,16 @@ assign_record_type_typmod(TupleDesc tupDesc)
 		/* First time through: initialize the hash table */
 		HASHCTL		ctl;
 
-		if (!CacheMemoryContext)
-			CreateCacheMemoryContext();
-
 		MemSet(&ctl, 0, sizeof(ctl));
 		ctl.keysize = REC_HASH_KEYS * sizeof(Oid);
 		ctl.entrysize = sizeof(RecordCacheEntry);
 		ctl.hash = tag_hash;
 		RecordCacheHash = hash_create("Record information cache", 64,
 									  &ctl, HASH_ELEM | HASH_FUNCTION);
+
+		/* Also make sure CacheMemoryContext exists */
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
 	}
 
 	/* Find or create a hashtable entry for this hash class */