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, 45 insertions, 45 deletions

diff --git a/src/backend/commands/creatinh.c b/src/backend/commands/creatinh.c
index a1d45d170a1..970782d6da3 100644
--- a/src/backend/commands/creatinh.c
+++ b/src/backend/commands/creatinh.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/creatinh.c,v 1.66 2000/11/13 09:16:55 inoue Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/creatinh.c,v 1.67 2000/11/16 22:30:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -408,11 +408,14 @@ MergeAttributes(List *schema, List *supers, List **supconstr)
 			 * form name, type and constraints
 			 */
 			attributeName = NameStr(attribute->attname);
-			tuple = SearchSysCacheTuple(TYPEOID,
+			tuple = SearchSysCache(TYPEOID,
 								   ObjectIdGetDatum(attribute->atttypid),
-										0, 0, 0);
-			Assert(HeapTupleIsValid(tuple));
-			attributeType = NameStr(((Form_pg_type) GETSTRUCT(tuple))->typname);
+								   0, 0, 0);
+			if (!HeapTupleIsValid(tuple))
+				elog(ERROR, "CREATE TABLE: cache lookup failed for type %u",
+					 attribute->atttypid);
+			attributeType = pstrdup(NameStr(((Form_pg_type) GETSTRUCT(tuple))->typname));
+			ReleaseSysCache(tuple);
 
 			/*
 			 * check validity
@@ -554,22 +557,25 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 	idList = NIL;
 	foreach(entry, supers)
 	{
+		Oid			entryOid;
 		Datum		datum[Natts_pg_inherits];
 		char		nullarr[Natts_pg_inherits];
 
-		tuple = SearchSysCacheTuple(RELNAME,
+		entryOid = GetSysCacheOid(RELNAME,
 								  PointerGetDatum(strVal(lfirst(entry))),
-									0, 0, 0);
-		AssertArg(HeapTupleIsValid(tuple));
+								  0, 0, 0);
+		if (!OidIsValid(entryOid))
+			elog(ERROR, "StoreCatalogInheritance: cache lookup failed for relation \"%s\"",
+				 strVal(lfirst(entry)));
 
 		/*
 		 * build idList for use below
 		 */
-		idList = lappendi(idList, tuple->t_data->t_oid);
+		idList = lappendi(idList, entryOid);
 
-		datum[0] = ObjectIdGetDatum(relationId);		/* inhrel */
-		datum[1] = ObjectIdGetDatum(tuple->t_data->t_oid);		/* inhparent */
-		datum[2] = Int16GetDatum(seqNumber);	/* inhseqno */
+		datum[0] = ObjectIdGetDatum(relationId);	/* inhrel */
+		datum[1] = ObjectIdGetDatum(entryOid);		/* inhparent */
+		datum[2] = Int16GetDatum(seqNumber);		/* inhseqno */
 
 		nullarr[0] = ' ';
 		nullarr[1] = ' ';
@@ -624,11 +630,10 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 
 		for (number = 1;; number += 1)
 		{
-			tuple = SearchSysCacheTuple(INHRELID,
-										ObjectIdGetDatum(id),
-										Int16GetDatum(number),
-										0, 0);
-
+			tuple = SearchSysCache(INHRELID,
+								   ObjectIdGetDatum(id),
+								   Int16GetDatum(number),
+								   0, 0);
 			if (!HeapTupleIsValid(tuple))
 				break;
 
@@ -636,6 +641,8 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 									 GETSTRUCT(tuple))->inhparent,
 									NIL);
 
+			ReleaseSysCache(tuple);
+
 			current = lnext(current);
 		}
 		lnext(current) = next;
@@ -746,35 +753,28 @@ checkAttrExists(const char *attributeName, const char *attributeType, List *sche
 static void
 setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
 {
-        Relation        relationRelation;
-        HeapTuple       tuple;
-        Relation        idescs[Num_pg_class_indices];
-
-        /*
-         * Lock a relation given its Oid. Go to the RelationRelation (i.e.
-         * pg_relation), find the appropriate tuple, and add the specified
-         * lock to it.
-         */
-        relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
-        tuple = SearchSysCacheTupleCopy(RELOID,
-                                    ObjectIdGetDatum(relationId),
-                                    0, 0, 0)
-;
-        Assert(HeapTupleIsValid(tuple));
-
-        ((Form_pg_class) GETSTRUCT(tuple))->relhassubclass = relhassubclass;
-        heap_update(relationRelation, &tuple->t_self, tuple, NULL);
-
-        /* keep the catalog indices up to date */
-        CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
-        CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple
-);
-        CatalogCloseIndices(Num_pg_class_indices, idescs);
-
-	heap_freetuple(tuple);
-        heap_close(relationRelation, RowExclusiveLock);
-}
+	Relation		relationRelation;
+	HeapTuple       tuple;
+	Relation        idescs[Num_pg_class_indices];
 
+	/*
+	 * Fetch a modifiable copy of the tuple, modify it, update pg_class.
+	 */
+	relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
+	tuple = SearchSysCacheCopy(RELOID,
+							   ObjectIdGetDatum(relationId),
+							   0, 0, 0);
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "setRelhassubclassInRelation: cache lookup failed for relation %u", relationId);
 
+	((Form_pg_class) GETSTRUCT(tuple))->relhassubclass = relhassubclass;
+	heap_update(relationRelation, &tuple->t_self, tuple, NULL);
 
+	/* keep the catalog indices up to date */
+	CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
+	CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple);
+	CatalogCloseIndices(Num_pg_class_indices, idescs);
 
+	heap_freetuple(tuple);
+	heap_close(relationRelation, RowExclusiveLock);
+}