First phase of memory management rewrite (see backend/utils/mmgr/README

for details).  It doesn't really do that much yet, since there are no
short-term memory contexts in the executor, but the infrastructure is
in place and long-term contexts are handled reasonably.  A few long-
standing bugs have been fixed, such as 'VACUUM; anything' in a single
query string crashing.  Also, out-of-memory is now considered a
recoverable ERROR, not FATAL.
Eliminate a large amount of crufty, now-dead code in and around
memory management.
Fix problem with holding off SIGTRAP, SIGSEGV, etc in postmaster and
backend startup.

src/backend/utils/cache/catcache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.67 2000/06/19 03:54:31 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.68 2000/06/28 03:32:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -60,10 +60,6 @@ static Datum cc_hashname(PG_FUNCTION_ARGS);
 
 static CatCache *Caches = NULL; /* head of list of caches */
 
-GlobalMemory CacheCxt;			/* context in which caches are allocated */
-
-/* CacheCxt is global because relcache uses it too. */
-
 
 /* ----------------
  *		EQPROC is used in CatalogCacheInitializeCache to find the equality
@@ -135,6 +131,28 @@ cc_hashname(PG_FUNCTION_ARGS)
 }
 
 
+/*
+ * Standard routine for creating cache context if it doesn't exist yet
+ *
+ * There are a lot of places (probably far more than necessary) that check
+ * whether CacheMemoryContext exists yet and want to create it if not.
+ * We centralize knowledge of exactly how to create it here.
+ */
+void
+CreateCacheMemoryContext(void)
+{
+	/* Purely for paranoia, check that context doesn't exist;
+	 * caller probably did so already.
+	 */
+	if (!CacheMemoryContext)
+		CacheMemoryContext = AllocSetContextCreate(TopMemoryContext,
+												   "CacheMemoryContext",
+												   ALLOCSET_DEFAULT_MINSIZE,
+												   ALLOCSET_DEFAULT_INITSIZE,
+												   ALLOCSET_DEFAULT_MAXSIZE);
+}
+
+
 /* --------------------------------
  *		CatalogCacheInitializeCache
  * --------------------------------
@@ -183,9 +201,10 @@ CatalogCacheInitializeCache(CatCache * cache,
 	 *	do not vanish at the end of a transaction
 	 * ----------------
 	 */
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
+
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	If no relation was passed we must open it to get access to
@@ -415,7 +434,7 @@ CatalogCacheComputeTupleHashIndex(CatCache * cacheInOutP,
 /* --------------------------------
  *		CatCacheRemoveCTup
  *
- *		NB: assumes caller has switched to CacheCxt
+ *		NB: assumes caller has switched to CacheMemoryContext
  * --------------------------------
  */
 static void
@@ -477,9 +496,10 @@ CatalogCacheIdInvalidate(int cacheId,	/* XXX */
 	 *	switch to the cache context for our memory allocations
 	 * ----------------
 	 */
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
+
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	inspect every cache that could contain the tuple
@@ -552,10 +572,10 @@ ResetSystemCache()
 	 *	do not vanish at the end of a transaction
 	 * ----------------
 	 */
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	here we purge the contents of all the caches
@@ -681,10 +701,10 @@ InitSysCache(char *relname,
 	 *	do not vanish at the end of a transaction
 	 * ----------------
 	 */
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	allocate a new cache structure
@@ -839,14 +859,14 @@ SearchSelfReferences(CatCache * cache)
 			HeapScanDesc sd;
 			MemoryContext oldcxt;
 
-			if (!CacheCxt)
-				CacheCxt = CreateGlobalMemory("Cache");
 			rel = heap_open(cache->relationId, AccessShareLock);
 			sd = heap_beginscan(rel, false, SnapshotNow, 1, cache->cc_skey);
 			ntp = heap_getnext(sd, 0);
 			if (!HeapTupleIsValid(ntp))
 				elog(ERROR, "SearchSelfReferences: tuple not found");
-			oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+			if (!CacheMemoryContext)
+				CreateCacheMemoryContext();
+			oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 			indexSelfTuple = heap_copytuple(ntp);
 			MemoryContextSwitchTo(oldcxt);
 			heap_endscan(sd);
@@ -868,14 +888,14 @@ SearchSelfReferences(CatCache * cache)
 			HeapScanDesc sd;
 			MemoryContext oldcxt;
 
-			if (!CacheCxt)
-				CacheCxt = CreateGlobalMemory("Cache");
 			rel = heap_open(cache->relationId, AccessShareLock);
 			sd = heap_beginscan(rel, false, SnapshotNow, 1, cache->cc_skey);
 			ntp = heap_getnext(sd, 0);
 			if (!HeapTupleIsValid(ntp))
 				elog(ERROR, "SearchSelfReferences: tuple not found");
-			oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+			if (!CacheMemoryContext)
+				CreateCacheMemoryContext();
+			oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 			operatorSelfTuple[lookup_oid - MIN_OIDCMP] = heap_copytuple(ntp);
 			MemoryContextSwitchTo(oldcxt);
 			heap_endscan(sd);
@@ -908,7 +928,6 @@ SearchSysCache(CatCache * cache,
 	CatCTup    *nct2;
 	Dlelem	   *elt;
 	HeapTuple	ntp = NULL;
-
 	Relation	relation;
 	MemoryContext oldcxt;
 
@@ -1020,10 +1039,10 @@ SearchSysCache(CatCache * cache,
 	 * ----------------
 	 */
 
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	Scan the relation to find the tuple.  If there's an index, and
@@ -1060,12 +1079,13 @@ SearchSysCache(CatCache * cache,
 		 */
 		if (HeapTupleIsValid(indextp))
 		{
-			MemoryContextSwitchTo((MemoryContext) CacheCxt);
+			MemoryContextSwitchTo(CacheMemoryContext);
 			ntp = heap_copytuple(indextp);
+			/* this switch is probably not needed anymore: */
 			MemoryContextSwitchTo(oldcxt);
 			heap_freetuple(indextp);
 		}
-		MemoryContextSwitchTo((MemoryContext) CacheCxt);
+		MemoryContextSwitchTo(CacheMemoryContext);
 	}
 	else
 	{
@@ -1084,7 +1104,7 @@ SearchSysCache(CatCache * cache,
 
 		ntp = heap_getnext(sd, 0);
 
-		MemoryContextSwitchTo((MemoryContext) CacheCxt);
+		MemoryContextSwitchTo(CacheMemoryContext);
 
 		if (HeapTupleIsValid(ntp))
 		{
@@ -1097,7 +1117,7 @@ SearchSysCache(CatCache * cache,
 
 		heap_endscan(sd);
 
-		MemoryContextSwitchTo((MemoryContext) CacheCxt);
+		MemoryContextSwitchTo(CacheMemoryContext);
 	}
 
 	cache->busy = false;
@@ -1205,9 +1225,10 @@ RelationInvalidateCatalogCacheTuple(Relation relation,
 	 *	switch to the cache memory context
 	 * ----------------
 	 */
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
+
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	for each cache

src/backend/utils/cache/relcache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.103 2000/06/19 23:40:48 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.104 2000/06/28 03:32:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -917,10 +917,10 @@ RelationBuildDesc(RelationBuildDescInfo buildinfo,
 	/* ----------------
 	 *	allocate storage for the relation descriptor,
 	 *	initialize relation->rd_rel and get the access method id.
-	 *	The storage is allocated in memory context CacheCxt.
+	 *	The storage is allocated in memory context CacheMemoryContext.
 	 * ----------------
 	 */
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 	relation = AllocateRelationDesc(oldrelation, natts, relp);
 	relam = relation->rd_rel->relam;
 
@@ -1383,7 +1383,7 @@ RelationClearRelation(Relation relation, bool rebuildIt)
 	if (relation->rd_isnailed)
 		return;
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/*
 	 * Remove relation from hash tables
@@ -1574,7 +1574,7 @@ RelationForgetRelation(Oid rid)
 			List	   *curr;
 			List	   *prev = NIL;
 
-			oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+			oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 			foreach(curr, newlyCreatedRelns)
 			{
@@ -1731,10 +1731,7 @@ RelationRegisterRelation(Relation relation)
 {
 	MemoryContext oldcxt;
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
-
-	if (oldcxt != (MemoryContext) CacheCxt)
-		elog(NOIND, "RelationRegisterRelation: WARNING: Context != CacheCxt");
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	RelationInitLockInfo(relation);
 
@@ -1769,7 +1766,7 @@ RelationPurgeLocalRelation(bool xactCommitted)
 	if (newlyCreatedRelns == NULL)
 		return;
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	while (newlyCreatedRelns)
 	{
@@ -1822,10 +1819,10 @@ RelationInitialize(void)
 	 *	switch to cache memory context
 	 * ----------------
 	 */
-	if (!CacheCxt)
-		CacheCxt = CreateGlobalMemory("Cache");
+	if (!CacheMemoryContext)
+		CreateCacheMemoryContext();
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	/* ----------------
 	 *	create global caches
@@ -2186,7 +2183,7 @@ RelationGetIndexList(Relation relation)
 	heap_close(indrel, AccessShareLock);
 
 	/* Now save a copy of the completed list in the relcache entry. */
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 	relation->rd_indexlist = listCopy(result);
 	relation->rd_indexfound = true;
 	MemoryContextSwitchTo(oldcxt);

src/backend/utils/cache/temprel.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/Attic/temprel.c,v 1.24 2000/06/20 06:41:12 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/Attic/temprel.c,v 1.25 2000/06/28 03:32:25 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -67,7 +67,7 @@ create_temp_relation(const char *relname, HeapTuple pg_class_tuple)
 	MemoryContext oldcxt;
 	TempTable  *temp_rel;
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	temp_rel = (TempTable *) palloc(sizeof(TempTable));
 	temp_rel->user_relname = (char *) palloc(NAMEDATALEN);
@@ -135,7 +135,7 @@ remove_temp_relation(Oid relid)
 	List	   *l,
 			   *prev;
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	prev = NIL;
 	l = temp_rels;
@@ -185,7 +185,7 @@ invalidate_temp_relations(void)
 	List	   *l,
 			   *prev;
 
-	oldcxt = MemoryContextSwitchTo((MemoryContext) CacheCxt);
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
 	prev = NIL;
 	l = temp_rels;