From a933ee38bbb8dffbc48a3363a94ff6f2a9f7964d Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 16 Nov 2000 22:30:52 +0000
Subject: 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.

---
 src/backend/access/index/istrat.c | 61 ++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 29 deletions(-)

(limited to 'src/backend/access/index/istrat.c')

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));
-- 
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