Clean up various to-do items associated with system indexes:

pg_database now has unique indexes on oid and on datname.
pg_shadow now has unique indexes on usename and on usesysid.
pg_am now has unique index on oid.
pg_opclass now has unique index on oid.
pg_amproc now has unique index on amid+amopclaid+amprocnum.
Remove pg_rewrite's unnecessary index on oid, delete unused RULEOID syscache.
Remove index on pg_listener and associated syscache for performance reasons
(caching rows that are certain to change before you need 'em again is
rather pointless).
Change pg_attrdef's nonunique index on adrelid into a unique index on
adrelid+adnum.

Fix various incorrect settings of pg_class.relisshared, make that the
primary reference point for whether a relation is shared or not.
IsSharedSystemRelationName() is now only consulted to initialize relisshared
during initial creation of tables and indexes.  In theory we might now
support shared user relations, though it's not clear how one would get
entries for them into pg_class &etc of multiple databases.

Fix recently reported bug that pg_attribute rows created for an index all have
the same OID.  (Proof that non-unique OID doesn't matter unless it's
actually used to do lookups ;-))

There's no need to treat pg_trigger, pg_attrdef, pg_relcheck as bootstrap
relations.  Convert them into plain system catalogs without hardwired
entries in pg_class and friends.

Unify global.bki and template1.bki into a single init script postgres.bki,
since the alleged distinction between them was misleading and pointless.
Not to mention that it didn't work for setting up indexes on shared
system relations.

Rationalize locking of pg_shadow, pg_group, pg_attrdef (no need to use
AccessExclusiveLock where ExclusiveLock or even RowExclusiveLock will do).
Also, hold locks until transaction commit where necessary.

1 files changed, 120 insertions, 107 deletions

diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index 1eb29dcc99a..5fda53d02c6 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.77 2001/03/22 03:59:21 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.78 2001/06/12 05:55:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -80,7 +80,6 @@
 
 #include "access/heapam.h"
 #include "catalog/catname.h"
-#include "catalog/indexing.h"
 #include "catalog/pg_listener.h"
 #include "commands/async.h"
 #include "lib/dllist.h"
@@ -195,11 +194,12 @@ void
 Async_Listen(char *relname, int pid)
 {
 	Relation	lRel;
+	HeapScanDesc scan;
 	HeapTuple	tuple;
 	Datum		values[Natts_pg_listener];
 	char		nulls[Natts_pg_listener];
 	int			i;
-	TupleDesc	tupDesc;
+	bool		alreadyListener = false;
 
 	if (Trace_notify)
 		elog(DEBUG, "Async_Listen: %s", relname);
@@ -207,12 +207,23 @@ Async_Listen(char *relname, int pid)
 	lRel = heap_openr(ListenerRelationName, AccessExclusiveLock);
 
 	/* Detect whether we are already listening on this relname */
-	if (SearchSysCacheExists(LISTENREL,
-							 Int32GetDatum(pid),
-							 PointerGetDatum(relname),
-							 0, 0))
+	scan = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey) NULL);
+	while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
+	{
+		Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);
+
+		if (listener->listenerpid == pid &&
+			strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)
+		{
+			alreadyListener = true;
+			/* No need to scan the rest of the table */
+			break;
+		}
+	}
+	heap_endscan(scan);
+
+	if (alreadyListener)
 	{
-		/* No need to scan the rest of the table */
 		heap_close(lRel, AccessExclusiveLock);
 		elog(NOTICE, "Async_Listen: We are already listening on %s", relname);
 		return;
@@ -233,9 +244,10 @@ Async_Listen(char *relname, int pid)
 	values[i++] = (Datum) pid;
 	values[i++] = (Datum) 0;	/* no notifies pending */
 
-	tupDesc = lRel->rd_att;
-	tuple = heap_formtuple(tupDesc, values, nulls);
+	tuple = heap_formtuple(RelationGetDescr(lRel), values, nulls);
 	heap_insert(lRel, tuple);
+
+#ifdef NOT_USED					/* currently there are no indexes */
 	if (RelationGetForm(lRel)->relhasindex)
 	{
 		Relation	idescs[Num_pg_listener_indices];
@@ -244,6 +256,7 @@ Async_Listen(char *relname, int pid)
 		CatalogIndexInsert(idescs, Num_pg_listener_indices, lRel, tuple);
 		CatalogCloseIndices(Num_pg_listener_indices, idescs);
 	}
+#endif
 
 	heap_freetuple(tuple);
 
@@ -280,7 +293,8 @@ void
 Async_Unlisten(char *relname, int pid)
 {
 	Relation	lRel;
-	HeapTuple	lTuple;
+	HeapScanDesc scan;
+	HeapTuple	tuple;
 
 	/* Handle specially the `unlisten "*"' command */
 	if ((!relname) || (*relname == '\0') || (strcmp(relname, "*") == 0))
@@ -293,16 +307,26 @@ Async_Unlisten(char *relname, int pid)
 		elog(DEBUG, "Async_Unlisten %s", relname);
 
 	lRel = heap_openr(ListenerRelationName, AccessExclusiveLock);
-	/* Note we assume there can be only one matching tuple. */
-	lTuple = SearchSysCache(LISTENREL,
-							Int32GetDatum(pid),
-							PointerGetDatum(relname),
-							0, 0);
-	if (HeapTupleIsValid(lTuple))
+
+	scan = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey) NULL);
+	while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
 	{
-		simple_heap_delete(lRel, &lTuple->t_self);
-		ReleaseSysCache(lTuple);
+		Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(tuple);
+
+		if (listener->listenerpid == pid &&
+			strncmp(NameStr(listener->relname), relname, NAMEDATALEN) == 0)
+		{
+			/* Found the matching tuple, delete it */
+			simple_heap_delete(lRel, &tuple->t_self);
+			/*
+			 * We assume there can be only one match, so no need
+			 * to scan the rest of the table
+			 */
+			break;
+		}
 	}
+	heap_endscan(scan);
+
 	heap_close(lRel, AccessExclusiveLock);
 
 	/*
@@ -332,7 +356,7 @@ Async_UnlistenAll()
 {
 	Relation	lRel;
 	TupleDesc	tdesc;
-	HeapScanDesc sRel;
+	HeapScanDesc scan;
 	HeapTuple	lTuple;
 	ScanKeyData key[1];
 
@@ -347,12 +371,12 @@ Async_UnlistenAll()
 						   Anum_pg_listener_pid,
 						   F_INT4EQ,
 						   Int32GetDatum(MyProcPid));
-	sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, key);
+	scan = heap_beginscan(lRel, 0, SnapshotNow, 1, key);
 
-	while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0)))
+	while (HeapTupleIsValid(lTuple = heap_getnext(scan, 0)))
 		simple_heap_delete(lRel, &lTuple->t_self);
 
-	heap_endscan(sRel);
+	heap_endscan(scan);
 	heap_close(lRel, AccessExclusiveLock);
 }
 
@@ -418,16 +442,12 @@ AtCommit_Notify()
 {
 	Relation	lRel;
 	TupleDesc	tdesc;
-	HeapScanDesc sRel;
+	HeapScanDesc scan;
 	HeapTuple	lTuple,
 				rTuple;
-	Datum		d,
-				value[Natts_pg_listener];
+	Datum		value[Natts_pg_listener];
 	char		repl[Natts_pg_listener],
 				nulls[Natts_pg_listener];
-	bool		isnull;
-	char	   *relname;
-	int32		listenerPID;
 
 	if (!pendingNotifies)
 		return;					/* no NOTIFY statements in this
@@ -446,10 +466,6 @@ AtCommit_Notify()
 	if (Trace_notify)
 		elog(DEBUG, "AtCommit_Notify");
 
-	lRel = heap_openr(ListenerRelationName, AccessExclusiveLock);
-	tdesc = RelationGetDescr(lRel);
-	sRel = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey) NULL);
-
 	/* preset data to update notify column to MyProcPid */
 	nulls[0] = nulls[1] = nulls[2] = ' ';
 	repl[0] = repl[1] = repl[2] = ' ';
@@ -457,83 +473,81 @@ AtCommit_Notify()
 	value[0] = value[1] = value[2] = (Datum) 0;
 	value[Anum_pg_listener_notify - 1] = Int32GetDatum(MyProcPid);
 
-	while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0)))
+	lRel = heap_openr(ListenerRelationName, AccessExclusiveLock);
+	tdesc = RelationGetDescr(lRel);
+	scan = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey) NULL);
+
+	while (HeapTupleIsValid(lTuple = heap_getnext(scan, 0)))
 	{
-		d = heap_getattr(lTuple, Anum_pg_listener_relname, tdesc, &isnull);
-		relname = (char *) DatumGetPointer(d);
+		Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(lTuple);
+		char	   *relname = NameStr(listener->relname);
+		int32		listenerPID = listener->listenerpid;
 
-		if (AsyncExistsPendingNotify(relname))
+		if (! AsyncExistsPendingNotify(relname))
+			continue;
+
+		if (listenerPID == MyProcPid)
 		{
-			d = heap_getattr(lTuple, Anum_pg_listener_pid, tdesc, &isnull);
-			listenerPID = DatumGetInt32(d);
+			/*
+			 * Self-notify: no need to bother with table update.
+			 * Indeed, we *must not* clear the notification field in
+			 * this path, or we could lose an outside notify, which'd
+			 * be bad for applications that ignore self-notify messages.
+			 */
 
-			if (listenerPID == MyProcPid)
-			{
+			if (Trace_notify)
+				elog(DEBUG, "AtCommit_Notify: notifying self");
 
+			NotifyMyFrontEnd(relname, listenerPID);
+		}
+		else
+		{
+			if (Trace_notify)
+				elog(DEBUG, "AtCommit_Notify: notifying pid %d",
+					 listenerPID);
+
+			/*
+			 * If someone has already notified this listener, we don't
+			 * bother modifying the table, but we do still send a
+			 * SIGUSR2 signal, just in case that backend missed the
+			 * earlier signal for some reason.	It's OK to send the
+			 * signal first, because the other guy can't read
+			 * pg_listener until we unlock it.
+			 */
+			if (kill(listenerPID, SIGUSR2) < 0)
+			{
 				/*
-				 * Self-notify: no need to bother with table update.
-				 * Indeed, we *must not* clear the notification field in
-				 * this path, or we could lose an outside notify, which'd
-				 * be bad for applications that ignore self-notify
-				 * messages.
+				 * Get rid of pg_listener entry if it refers to a PID
+				 * that no longer exists.  Presumably, that backend
+				 * crashed without deleting its pg_listener entries.
+				 * This code used to only delete the entry if
+				 * errno==ESRCH, but as far as I can see we should
+				 * just do it for any failure (certainly at least for
+				 * EPERM too...)
 				 */
-
-				if (Trace_notify)
-					elog(DEBUG, "AtCommit_Notify: notifying self");
-
-				NotifyMyFrontEnd(relname, listenerPID);
+				simple_heap_delete(lRel, &lTuple->t_self);
 			}
-			else
+			else if (listener->notification == 0)
 			{
-				if (Trace_notify)
-					elog(DEBUG, "AtCommit_Notify: notifying pid %d", listenerPID);
+				rTuple = heap_modifytuple(lTuple, lRel,
+										  value, nulls, repl);
+				simple_heap_update(lRel, &lTuple->t_self, rTuple);
 
-				/*
-				 * If someone has already notified this listener, we don't
-				 * bother modifying the table, but we do still send a
-				 * SIGUSR2 signal, just in case that backend missed the
-				 * earlier signal for some reason.	It's OK to send the
-				 * signal first, because the other guy can't read
-				 * pg_listener until we unlock it.
-				 */
-				if (kill(listenerPID, SIGUSR2) < 0)
+#ifdef NOT_USED					/* currently there are no indexes */
+				if (RelationGetForm(lRel)->relhasindex)
 				{
+					Relation	idescs[Num_pg_listener_indices];
 
-					/*
-					 * Get rid of pg_listener entry if it refers to a PID
-					 * that no longer exists.  Presumably, that backend
-					 * crashed without deleting its pg_listener entries.
-					 * This code used to only delete the entry if
-					 * errno==ESRCH, but as far as I can see we should
-					 * just do it for any failure (certainly at least for
-					 * EPERM too...)
-					 */
-					simple_heap_delete(lRel, &lTuple->t_self);
-				}
-				else
-				{
-					d = heap_getattr(lTuple, Anum_pg_listener_notify,
-									 tdesc, &isnull);
-					if (DatumGetInt32(d) == 0)
-					{
-						rTuple = heap_modifytuple(lTuple, lRel,
-												  value, nulls, repl);
-						simple_heap_update(lRel, &lTuple->t_self, rTuple);
-						if (RelationGetForm(lRel)->relhasindex)
-						{
-							Relation	idescs[Num_pg_listener_indices];
-
-							CatalogOpenIndices(Num_pg_listener_indices, Name_pg_listener_indices, idescs);
-							CatalogIndexInsert(idescs, Num_pg_listener_indices, lRel, rTuple);
-							CatalogCloseIndices(Num_pg_listener_indices, idescs);
-						}
-					}
+					CatalogOpenIndices(Num_pg_listener_indices, Name_pg_listener_indices, idescs);
+					CatalogIndexInsert(idescs, Num_pg_listener_indices, lRel, rTuple);
+					CatalogCloseIndices(Num_pg_listener_indices, idescs);
 				}
+#endif
 			}
 		}
 	}
 
-	heap_endscan(sRel);
+	heap_endscan(scan);
 
 	/*
 	 * We do NOT release the lock on pg_listener here; we need to hold it
@@ -745,16 +759,12 @@ ProcessIncomingNotify(void)
 	Relation	lRel;
 	TupleDesc	tdesc;
 	ScanKeyData key[1];
-	HeapScanDesc sRel;
+	HeapScanDesc scan;
 	HeapTuple	lTuple,
 				rTuple;
-	Datum		d,
-				value[Natts_pg_listener];
+	Datum		value[Natts_pg_listener];
 	char		repl[Natts_pg_listener],
 				nulls[Natts_pg_listener];
-	bool		isnull;
-	char	   *relname;
-	int32		sourcePID;
 
 	if (Trace_notify)
 		elog(DEBUG, "ProcessIncomingNotify");
@@ -773,7 +783,7 @@ ProcessIncomingNotify(void)
 						   Anum_pg_listener_pid,
 						   F_INT4EQ,
 						   Int32GetDatum(MyProcPid));
-	sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, key);
+	scan = heap_beginscan(lRel, 0, SnapshotNow, 1, key);
 
 	/* Prepare data for rewriting 0 into notification field */
 	nulls[0] = nulls[1] = nulls[2] = ' ';
@@ -782,14 +792,14 @@ ProcessIncomingNotify(void)
 	value[0] = value[1] = value[2] = (Datum) 0;
 	value[Anum_pg_listener_notify - 1] = Int32GetDatum(0);
 
-	while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0)))
+	while (HeapTupleIsValid(lTuple = heap_getnext(scan, 0)))
 	{
-		d = heap_getattr(lTuple, Anum_pg_listener_notify, tdesc, &isnull);
-		sourcePID = DatumGetInt32(d);
+		Form_pg_listener listener = (Form_pg_listener) GETSTRUCT(lTuple);
+		char	   *relname = NameStr(listener->relname);
+		int32		sourcePID = listener->notification;
+
 		if (sourcePID != 0)
 		{
-			d = heap_getattr(lTuple, Anum_pg_listener_relname, tdesc, &isnull);
-			relname = (char *) DatumGetPointer(d);
 			/* Notify the frontend */
 
 			if (Trace_notify)
@@ -800,6 +810,8 @@ ProcessIncomingNotify(void)
 			/* Rewrite the tuple with 0 in notification column */
 			rTuple = heap_modifytuple(lTuple, lRel, value, nulls, repl);
 			simple_heap_update(lRel, &lTuple->t_self, rTuple);
+
+#ifdef NOT_USED					/* currently there are no indexes */
 			if (RelationGetForm(lRel)->relhasindex)
 			{
 				Relation	idescs[Num_pg_listener_indices];
@@ -808,9 +820,10 @@ ProcessIncomingNotify(void)
 				CatalogIndexInsert(idescs, Num_pg_listener_indices, lRel, rTuple);
 				CatalogCloseIndices(Num_pg_listener_indices, idescs);
 			}
+#endif
 		}
 	}
-	heap_endscan(sRel);
+	heap_endscan(scan);
 
 	/*
 	 * We do NOT release the lock on pg_listener here; we need to hold it
@@ -876,7 +889,7 @@ AsyncExistsPendingNotify(char *relname)
 		 p = DLGetSucc(p))
 	{
 		/* Use NAMEDATALEN for relname comparison.	  DZ - 26-08-1996 */
-		if (!strncmp((const char *) DLE_VAL(p), relname, NAMEDATALEN))
+		if (strncmp((const char *) DLE_VAL(p), relname, NAMEDATALEN) == 0)
 			return 1;
 	}