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, 24 insertions, 15 deletions

diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index a83a5b7c3ab..bc1a2b9918f 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.8 2000/10/16 17:08:05 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.9 2000/11/16 22:30:19 tgl Exp $
  *
 
  *-------------------------------------------------------------------------
@@ -58,8 +58,7 @@ static void del_stats(Oid relid, int attcnt, int *attnums);
 void
 analyze_rel(Oid relid, List *anal_cols2, int MESSAGE_LEVEL)
 {
-	HeapTuple	tuple,
-				typetuple;
+	HeapTuple	tuple;
 	Relation	onerel;
 	int32		i;
 	int			attr_cnt,
@@ -81,20 +80,26 @@ analyze_rel(Oid relid, List *anal_cols2, int MESSAGE_LEVEL)
 	 * Race condition -- if the pg_class tuple has gone away since the
 	 * last time we saw it, we don't need to vacuum it.
 	 */
-	tuple = SearchSysCacheTuple(RELOID,
-								ObjectIdGetDatum(relid),
-								0, 0, 0);
+	tuple = SearchSysCache(RELOID,
+						   ObjectIdGetDatum(relid),
+						   0, 0, 0);
+	if (!HeapTupleIsValid(tuple))
+	{
+		CommitTransactionCommand();
+		return;
+	}
 	/*
 	 * We can VACUUM ANALYZE any table except pg_statistic.
 	 * see update_relstats
 	 */
-	if (!HeapTupleIsValid(tuple) ||
-		strcmp(NameStr(((Form_pg_class) GETSTRUCT(tuple))->relname),
-				StatisticRelationName) == 0)
+	if (strcmp(NameStr(((Form_pg_class) GETSTRUCT(tuple))->relname),
+			   StatisticRelationName) == 0)
 	{
+		ReleaseSysCache(tuple);
 		CommitTransactionCommand();
 		return;
 	}
+	ReleaseSysCache(tuple);
 
 	onerel = heap_open(relid, AccessShareLock);
 
@@ -168,6 +173,7 @@ analyze_rel(Oid relid, List *anal_cols2, int MESSAGE_LEVEL)
 		{
 			pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
 			fmgr_info(pgopform->oprcode, &(stats->f_cmpeq));
+			ReleaseSysCache(func_operator);
 		}
 		else
 			stats->f_cmpeq.fn_addr = NULL;
@@ -178,6 +184,7 @@ analyze_rel(Oid relid, List *anal_cols2, int MESSAGE_LEVEL)
 			pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
 			fmgr_info(pgopform->oprcode, &(stats->f_cmplt));
 			stats->op_cmplt = oprid(func_operator);
+			ReleaseSysCache(func_operator);
 		}
 		else
 		{
@@ -190,17 +197,19 @@ analyze_rel(Oid relid, List *anal_cols2, int MESSAGE_LEVEL)
 		{
 			pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
 			fmgr_info(pgopform->oprcode, &(stats->f_cmpgt));
+			ReleaseSysCache(func_operator);
 		}
 		else
 			stats->f_cmpgt.fn_addr = NULL;
 
-		typetuple = SearchSysCacheTuple(TYPEOID,
-							 ObjectIdGetDatum(stats->attr->atttypid),
-										0, 0, 0);
-		if (HeapTupleIsValid(typetuple))
+		tuple = SearchSysCache(TYPEOID,
+							   ObjectIdGetDatum(stats->attr->atttypid),
+							   0, 0, 0);
+		if (HeapTupleIsValid(tuple))
 		{
-			stats->outfunc = ((Form_pg_type) GETSTRUCT(typetuple))->typoutput;
-			stats->typelem = ((Form_pg_type) GETSTRUCT(typetuple))->typelem;
+			stats->outfunc = ((Form_pg_type) GETSTRUCT(tuple))->typoutput;
+			stats->typelem = ((Form_pg_type) GETSTRUCT(tuple))->typelem;
+			ReleaseSysCache(tuple);
 		}
 		else
 		{