Change SearchSysCache coding conventions so that a reference count is

maintained for each cache entry.  A cache entry will not be freed until
the matching ReleaseSysCache call has been executed.  This eliminates
worries about cache entries getting dropped while still in use.  See
my posting to pg-hackers of even date for more info.

1 files changed, 32 insertions, 29 deletions

diff --git a/src/backend/access/index/istrat.c b/src/backend/access/index/istrat.c
index d6a966bcd44..681b80e1e86 100644
--- a/src/backend/access/index/istrat.c
+++ b/src/backend/access/index/istrat.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/index/Attic/istrat.c,v 1.46 2000/07/14 22:17:30 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/index/Attic/istrat.c,v 1.47 2000/11/16 22:30:16 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -482,9 +482,9 @@ OperatorRelationFillScanKeyEntry(Relation operatorRelation,
 
 	if (cachesearch)
 	{
-		tuple = SearchSysCacheTuple(OPEROID,
-									ObjectIdGetDatum(operatorObjectId),
-									0, 0, 0);
+		tuple = SearchSysCache(OPEROID,
+							   ObjectIdGetDatum(operatorObjectId),
+							   0, 0, 0);
 	}
 	else
 	{
@@ -505,24 +505,25 @@ OperatorRelationFillScanKeyEntry(Relation operatorRelation,
 	{
 		if (!cachesearch)
 			heap_endscan(scan);
-		elog(ERROR, "OperatorObjectIdFillScanKeyEntry: unknown operator %u",
+		elog(ERROR, "OperatorRelationFillScanKeyEntry: unknown operator %u",
 			 operatorObjectId);
 	}
 
 	entry->sk_flags = 0;
 	entry->sk_procedure = ((Form_pg_operator) GETSTRUCT(tuple))->oprcode;
-	fmgr_info(entry->sk_procedure, &entry->sk_func);
-	entry->sk_nargs = entry->sk_func.fn_nargs;
 
-	if (!cachesearch)
+	if (cachesearch)
+		ReleaseSysCache(tuple);
+	else
 		heap_endscan(scan);
 
 	if (!RegProcedureIsValid(entry->sk_procedure))
-	{
 		elog(ERROR,
-		"OperatorObjectIdFillScanKeyEntry: no procedure for operator %u",
+			 "OperatorRelationFillScanKeyEntry: no procedure for operator %u",
 			 operatorObjectId);
-	}
+
+	fmgr_info(entry->sk_procedure, &entry->sk_func);
+	entry->sk_nargs = entry->sk_func.fn_nargs;
 }
 
 
@@ -547,16 +548,16 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 	HeapTuple	tuple;
 	Form_pg_index iform;
 	StrategyMap map;
-	AttrNumber	attributeNumber;
-	int			attributeIndex;
+	AttrNumber	attNumber;
+	int			attIndex;
 	Oid			operatorClassObjectId[INDEX_MAX_KEYS];
 	bool		cachesearch = (!IsBootstrapProcessingMode()) && IsCacheInitialized();
 
 	if (cachesearch)
 	{
-		tuple = SearchSysCacheTuple(INDEXRELID,
-									ObjectIdGetDatum(indexObjectId),
-									0, 0, 0);
+		tuple = SearchSysCache(INDEXRELID,
+							   ObjectIdGetDatum(indexObjectId),
+							   0, 0, 0);
 	}
 	else
 	{
@@ -583,19 +584,23 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 	 * XXX note that the following assumes the INDEX tuple is well formed
 	 * and that the *key and *class are 0 terminated.
 	 */
-	for (attributeIndex = 0; attributeIndex < maxAttributeNumber; attributeIndex++)
+	for (attIndex = 0; attIndex < maxAttributeNumber; attIndex++)
 	{
-		if (!OidIsValid(iform->indkey[attributeIndex]))
+		if (!OidIsValid(iform->indkey[attIndex]))
 		{
-			if (attributeIndex == InvalidAttrNumber)
+			if (attIndex == InvalidAttrNumber)
 				elog(ERROR, "IndexSupportInitialize: no pg_index tuple");
 			break;
 		}
 
-		operatorClassObjectId[attributeIndex] = iform->indclass[attributeIndex];
+		operatorClassObjectId[attIndex] = iform->indclass[attIndex];
 	}
 
-	if (!cachesearch)
+	if (cachesearch)
+	{
+		ReleaseSysCache(tuple);
+	}
+	else
 	{
 		heap_endscan(scan);
 		heap_close(relation, AccessShareLock);
@@ -614,20 +619,19 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 		relation = heap_openr(AccessMethodProcedureRelationName,
 							  AccessShareLock);
 
-		for (attributeNumber = 1; attributeNumber <= maxAttributeNumber;
-			 attributeNumber++)
+		for (attNumber = 1; attNumber <= maxAttributeNumber; attNumber++)
 		{
 			int16		support;
 			Form_pg_amproc aform;
 			RegProcedure *loc;
 
-			loc = &indexSupport[((attributeNumber - 1) * maxSupportNumber)];
+			loc = &indexSupport[((attNumber - 1) * maxSupportNumber)];
 
 			for (support = 0; support < maxSupportNumber; ++support)
 				loc[support] = InvalidOid;
 
 			entry[1].sk_argument =
-				ObjectIdGetDatum(operatorClassObjectId[attributeNumber - 1]);
+				ObjectIdGetDatum(operatorClassObjectId[attNumber - 1]);
 
 			scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);
 
@@ -654,17 +658,16 @@ IndexSupportInitialize(IndexStrategy indexStrategy,
 	relation = heap_openr(AccessMethodOperatorRelationName, AccessShareLock);
 	operatorRelation = heap_openr(OperatorRelationName, AccessShareLock);
 
-	for (attributeNumber = maxAttributeNumber; attributeNumber > 0;
-		 attributeNumber--)
+	for (attNumber = maxAttributeNumber; attNumber > 0; attNumber--)
 	{
 		StrategyNumber strategy;
 
 		entry[1].sk_argument =
-			ObjectIdGetDatum(operatorClassObjectId[attributeNumber - 1]);
+			ObjectIdGetDatum(operatorClassObjectId[attNumber - 1]);
 
 		map = IndexStrategyGetStrategyMap(indexStrategy,
 										  maxStrategyNumber,
-										  attributeNumber);
+										  attNumber);
 
 		for (strategy = 1; strategy <= maxStrategyNumber; strategy++)
 			ScanKeyEntrySetIllegal(StrategyMapGetScanKeyEntry(map, strategy));