A bunch of changes aimed at reducing backend startup time...

Improve 'pg_internal.init' relcache entry preload mechanism so that it is
safe to use for all system catalogs, and arrange to preload a realistic
set of system-catalog entries instead of only the three nailed-in-cache
indexes that were formerly loaded this way.  Fix mechanism for deleting
out-of-date pg_internal.init files: this must be synchronized with transaction
commit, not just done at random times within transactions.  Drive it off
relcache invalidation mechanism so that no special-case tests are needed.

Cache additional information in relcache entries for indexes (their pg_index
tuples and index-operator OIDs) to eliminate repeated lookups.  Also cache
index opclass info at the per-opclass level to avoid repeated lookups during
relcache load.

Generalize 'systable scan' utilities originally developed by Hiroshi,
move them into genam.c, use in a number of places where there was formerly
ugly code for choosing either heap or index scan.  In particular this allows
simplification of the logic that prevents infinite recursion between syscache
and relcache during startup: we can easily switch to heapscans in relcache.c
when and where needed to avoid recursion, so IndexScanOK becomes simpler and
does not need any expensive initialization.

Eliminate useless opening of a heapscan data structure while doing an indexscan
(this saves an mdnblocks call and thus at least one kernel call).

1 files changed, 47 insertions, 122 deletions

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 528e53ee47d..402ff51e4bc 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.101 2002/01/15 16:52:47 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.102 2002/02/19 20:11:12 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -56,7 +56,7 @@ CreateTrigger(CreateTrigStmt *stmt)
 	char		nulls[Natts_pg_trigger];
 	Relation	rel;
 	Relation	tgrel;
-	HeapScanDesc tgscan;
+	SysScanDesc	tgscan;
 	ScanKeyData key;
 	Relation	pgrel;
 	HeapTuple	tuple;
@@ -151,8 +151,9 @@ CreateTrigger(CreateTrigStmt *stmt)
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
 						   F_OIDEQ,
 						   ObjectIdGetDatum(RelationGetRelid(rel)));
-	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);
-	while (HeapTupleIsValid(tuple = heap_getnext(tgscan, 0)))
+	tgscan = systable_beginscan(tgrel, TriggerRelidIndex, true,
+								SnapshotNow, 1, &key);
+	while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
 	{
 		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
 
@@ -161,7 +162,7 @@ CreateTrigger(CreateTrigStmt *stmt)
 				 stmt->trigname, stmt->relname);
 		found++;
 	}
-	heap_endscan(tgscan);
+	systable_endscan(tgscan);
 
 	/*
 	 * Find and validate the trigger function.
@@ -311,7 +312,7 @@ DropTrigger(DropTrigStmt *stmt)
 {
 	Relation	rel;
 	Relation	tgrel;
-	HeapScanDesc tgscan;
+	SysScanDesc	tgscan;
 	ScanKeyData key;
 	Relation	pgrel;
 	HeapTuple	tuple;
@@ -343,8 +344,9 @@ DropTrigger(DropTrigStmt *stmt)
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
 						   F_OIDEQ,
 						   ObjectIdGetDatum(RelationGetRelid(rel)));
-	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);
-	while (HeapTupleIsValid(tuple = heap_getnext(tgscan, 0)))
+	tgscan = systable_beginscan(tgrel, TriggerRelidIndex, true,
+								SnapshotNow, 1, &key);
+	while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
 	{
 		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
 
@@ -359,14 +361,15 @@ DropTrigger(DropTrigStmt *stmt)
 		else
 			found++;
 	}
+	systable_endscan(tgscan);
+	heap_close(tgrel, RowExclusiveLock);
+
 	if (tgfound == 0)
 		elog(ERROR, "DropTrigger: there is no trigger %s on relation %s",
 			 stmt->trigname, stmt->relname);
 	if (tgfound > 1)
 		elog(NOTICE, "DropTrigger: found (and deleted) %d triggers %s on relation %s",
 			 tgfound, stmt->trigname, stmt->relname);
-	heap_endscan(tgscan);
-	heap_close(tgrel, RowExclusiveLock);
 
 	/*
 	 * Update relation's pg_class entry.  Crucial side-effect: other
@@ -406,7 +409,7 @@ void
 RelationRemoveTriggers(Relation rel)
 {
 	Relation	tgrel;
-	HeapScanDesc tgscan;
+	SysScanDesc	tgscan;
 	ScanKeyData key;
 	HeapTuple	tup;
 	bool		found = false;
@@ -415,10 +418,10 @@ RelationRemoveTriggers(Relation rel)
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
 						   F_OIDEQ,
 						   ObjectIdGetDatum(RelationGetRelid(rel)));
+	tgscan = systable_beginscan(tgrel, TriggerRelidIndex, true,
+								SnapshotNow, 1, &key);
 
-	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);
-
-	while (HeapTupleIsValid(tup = heap_getnext(tgscan, 0)))
+	while (HeapTupleIsValid(tup = systable_getnext(tgscan)))
 	{
 		/* Delete any comments associated with this trigger */
 		DeleteComments(tup->t_data->t_oid, RelationGetRelid(tgrel));
@@ -428,7 +431,7 @@ RelationRemoveTriggers(Relation rel)
 		found = true;
 	}
 
-	heap_endscan(tgscan);
+	systable_endscan(tgscan);
 
 	/*
 	 * If we deleted any triggers, must update pg_class entry and advance
@@ -468,9 +471,10 @@ RelationRemoveTriggers(Relation rel)
 	ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgconstrrelid,
 						   F_OIDEQ,
 						   ObjectIdGetDatum(RelationGetRelid(rel)));
+	tgscan = systable_beginscan(tgrel, TriggerConstrRelidIndex, true,
+								SnapshotNow, 1, &key);
 
-	tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &key);
-	while (HeapTupleIsValid(tup = heap_getnext(tgscan, 0)))
+	while (HeapTupleIsValid(tup = systable_getnext(tgscan)))
 	{
 		Form_pg_trigger pg_trigger;
 		Relation	refrel;
@@ -500,7 +504,7 @@ RelationRemoveTriggers(Relation rel)
 		pfree(stmt.relname);
 		pfree(stmt.trigname);
 	}
-	heap_endscan(tgscan);
+	systable_endscan(tgscan);
 
 	heap_close(tgrel, RowExclusiveLock);
 }
@@ -518,69 +522,33 @@ RelationBuildTriggers(Relation relation)
 	TriggerDesc *trigdesc;
 	int			ntrigs = relation->rd_rel->reltriggers;
 	Trigger    *triggers = NULL;
-	Trigger    *build;
+	int			found = 0;
 	Relation	tgrel;
-	Form_pg_trigger pg_trigger;
-	Relation	irel = (Relation) NULL;
 	ScanKeyData skey;
-	HeapTupleData tuple;
-	IndexScanDesc sd = (IndexScanDesc) NULL;
-	HeapScanDesc tgscan = (HeapScanDesc) NULL;
+	SysScanDesc	tgscan;
 	HeapTuple	htup;
-	RetrieveIndexResult indexRes;
-	Buffer		buffer;
 	struct varlena *val;
 	bool		isnull;
-	int			found;
-	bool		hasindex;
-
-	trigdesc = (TriggerDesc *) MemoryContextAlloc(CacheMemoryContext,
-												  sizeof(TriggerDesc));
-	MemSet(trigdesc, 0, sizeof(TriggerDesc));
 
 	ScanKeyEntryInitialize(&skey,
 						   (bits16) 0x0,
-						   (AttrNumber) 1,
+						   (AttrNumber) Anum_pg_trigger_tgrelid,
 						   (RegProcedure) F_OIDEQ,
 						   ObjectIdGetDatum(RelationGetRelid(relation)));
 
 	tgrel = heap_openr(TriggerRelationName, AccessShareLock);
-	hasindex = (tgrel->rd_rel->relhasindex && !IsIgnoringSystemIndexes());
-	if (hasindex)
-	{
-		irel = index_openr(TriggerRelidIndex);
-		sd = index_beginscan(irel, false, 1, &skey);
-	}
-	else
-		tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &skey);
+	tgscan = systable_beginscan(tgrel, TriggerRelidIndex, true,
+								SnapshotNow, 1, &skey);
 
-	for (found = 0;;)
+	while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
 	{
-		if (hasindex)
-		{
-			indexRes = index_getnext(sd, ForwardScanDirection);
-			if (!indexRes)
-				break;
+		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
+		Trigger    *build;
 
-			tuple.t_self = indexRes->heap_iptr;
-			heap_fetch(tgrel, SnapshotNow, &tuple, &buffer, sd);
-			pfree(indexRes);
-			if (!tuple.t_data)
-				continue;
-			htup = &tuple;
-		}
-		else
-		{
-			htup = heap_getnext(tgscan, 0);
-			if (!HeapTupleIsValid(htup))
-				break;
-		}
 		if (found == ntrigs)
 			elog(ERROR, "RelationBuildTriggers: unexpected record found for rel %s",
 				 RelationGetRelationName(relation));
 
-		pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
-
 		if (triggers == NULL)
 			triggers = (Trigger *) MemoryContextAlloc(CacheMemoryContext,
 													  sizeof(Trigger));
@@ -628,25 +596,20 @@ RelationBuildTriggers(Relation relation)
 			build->tgargs = NULL;
 
 		found++;
-		if (hasindex)
-			ReleaseBuffer(buffer);
 	}
 
-	if (found < ntrigs)
+	systable_endscan(tgscan);
+	heap_close(tgrel, AccessShareLock);
+
+	if (found != ntrigs)
 		elog(ERROR, "RelationBuildTriggers: %d record(s) not found for rel %s",
 			 ntrigs - found,
 			 RelationGetRelationName(relation));
 
-	if (hasindex)
-	{
-		index_endscan(sd);
-		index_close(irel);
-	}
-	else
-		heap_endscan(tgscan);
-	heap_close(tgrel, AccessShareLock);
-
 	/* Build trigdesc */
+	trigdesc = (TriggerDesc *) MemoryContextAlloc(CacheMemoryContext,
+												  sizeof(TriggerDesc));
+	MemSet(trigdesc, 0, sizeof(TriggerDesc));
 	trigdesc->triggers = triggers;
 	trigdesc->numtriggers = ntrigs;
 	for (found = 0; found < ntrigs; found++)
@@ -1741,14 +1704,12 @@ void
 DeferredTriggerSetState(ConstraintsSetStmt *stmt)
 {
 	Relation	tgrel;
-	Relation	irel = (Relation) NULL;
 	List	   *l;
 	List	   *ls;
 	List	   *loid = NIL;
 	MemoryContext oldcxt;
 	bool		found;
 	DeferredTriggerStatus state;
-	bool		hasindex;
 
 	/*
 	 * Handle SET CONSTRAINTS ALL ...
@@ -1817,21 +1778,12 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
 	 * ----------
 	 */
 	tgrel = heap_openr(TriggerRelationName, AccessShareLock);
-	hasindex = (tgrel->rd_rel->relhasindex && !IsIgnoringSystemIndexes());
-	if (hasindex)
-		irel = index_openr(TriggerConstrNameIndex);
 
 	foreach(l, stmt->constraints)
 	{
 		ScanKeyData skey;
-		HeapTupleData tuple;
-		IndexScanDesc sd = (IndexScanDesc) NULL;
-		HeapScanDesc tgscan = (HeapScanDesc) NULL;
+		SysScanDesc	tgscan;
 		HeapTuple	htup;
-		RetrieveIndexResult indexRes;
-		Buffer		buffer;
-		Form_pg_trigger pg_trigger;
-		Oid			constr_oid;
 
 		/*
 		 * Check that only named constraints are set explicitly
@@ -1844,47 +1796,28 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
 		 */
 		ScanKeyEntryInitialize(&skey,
 							   (bits16) 0x0,
-							   (AttrNumber) 1,
+							   (AttrNumber) Anum_pg_trigger_tgconstrname,
 							   (RegProcedure) F_NAMEEQ,
 							   PointerGetDatum((char *) lfirst(l)));
 
-		if (hasindex)
-			sd = index_beginscan(irel, false, 1, &skey);
-		else
-			tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &skey);
+		tgscan = systable_beginscan(tgrel, TriggerConstrNameIndex, true,
+									SnapshotNow, 1, &skey);
 
 		/*
 		 * ... and search for the constraint trigger row
 		 */
 		found = false;
-		for (;;)
-		{
-			if (hasindex)
-			{
-				indexRes = index_getnext(sd, ForwardScanDirection);
-				if (!indexRes)
-					break;
 
-				tuple.t_self = indexRes->heap_iptr;
-				heap_fetch(tgrel, SnapshotNow, &tuple, &buffer, sd);
-				pfree(indexRes);
-				if (!tuple.t_data)
-					continue;
-				htup = &tuple;
-			}
-			else
-			{
-				htup = heap_getnext(tgscan, 0);
-				if (!HeapTupleIsValid(htup))
-					break;
-			}
+		while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
+		{
+			Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
+			Oid			constr_oid;
 
 			/*
 			 * If we found some, check that they fit the deferrability but
 			 * skip ON <event> RESTRICT ones, since they are silently
 			 * never deferrable.
 			 */
-			pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
 			if (stmt->deferred && !pg_trigger->tgdeferrable &&
 				pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD &&
 				pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_DEL)
@@ -1894,24 +1827,16 @@ DeferredTriggerSetState(ConstraintsSetStmt *stmt)
 			constr_oid = htup->t_data->t_oid;
 			loid = lappendi(loid, constr_oid);
 			found = true;
-
-			if (hasindex)
-				ReleaseBuffer(buffer);
 		}
 
+		systable_endscan(tgscan);
+
 		/*
 		 * Not found ?
 		 */
 		if (!found)
 			elog(ERROR, "Constraint '%s' does not exist", (char *) lfirst(l));
-
-		if (hasindex)
-			index_endscan(sd);
-		else
-			heap_endscan(tgscan);
 	}
-	if (hasindex)
-		index_close(irel);
 	heap_close(tgrel, AccessShareLock);
 
 	if (!IsTransactionBlock())