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, 33 insertions, 21 deletions

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 63f39f2e4cb..478ae973e5c 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Id: analyze.c,v 1.165 2000/11/08 22:09:58 tgl Exp $
+ *	$Id: analyze.c,v 1.166 2000/11/16 22:30:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2598,9 +2598,8 @@ transformFkeyCheckAttrs(FkConstraint *fkconstraint)
 	Form_pg_attribute *pkrel_attrs;
 	List	   *indexoidlist,
 			   *indexoidscan;
-	Form_pg_index indexStruct = NULL;
 	int			i;
-	int found=0;
+	bool		found = false;
 
 	/* ----------
 	 * Open the referenced table and get the attributes list
@@ -2616,7 +2615,7 @@ transformFkeyCheckAttrs(FkConstraint *fkconstraint)
 	 * Get the list of index OIDs for the table from the relcache,
 	 * and look up each one in the pg_index syscache for each unique
 	 * one, and then compare the attributes we were given to those
-         * defined.
+	 * defined.
 	 * ----------
 	 */
 	indexoidlist = RelationGetIndexList(pkrel);
@@ -2625,27 +2624,34 @@ transformFkeyCheckAttrs(FkConstraint *fkconstraint)
 	{
 		Oid		indexoid = lfirsti(indexoidscan);
 		HeapTuple	indexTuple;
-		List *attrl;
-		indexTuple = SearchSysCacheTuple(INDEXRELID,
-										 ObjectIdGetDatum(indexoid),
-										 0, 0, 0);
+		Form_pg_index indexStruct;
+
+		indexTuple = SearchSysCache(INDEXRELID,
+									ObjectIdGetDatum(indexoid),
+									0, 0, 0);
 		if (!HeapTupleIsValid(indexTuple))
 			elog(ERROR, "transformFkeyGetPrimaryKey: index %u not found",
 				 indexoid);
 		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
 
-		if (indexStruct->indisunique) {
+		if (indexStruct->indisunique)
+		{
+			List *attrl;
+
 			/* go through the fkconstraint->pk_attrs list */
-			foreach(attrl, fkconstraint->pk_attrs) {
+			foreach(attrl, fkconstraint->pk_attrs)
+			{
 				Ident *attr=lfirst(attrl);
-				found=0;
+				found = false;
 				for (i = 0; i < INDEX_MAX_KEYS && indexStruct->indkey[i] != 0; i++)
 				{
 					int		pkattno = indexStruct->indkey[i];
-					if (pkattno>0) {
+					if (pkattno>0)
+					{
 						char *name = NameStr(pkrel_attrs[pkattno - 1]->attname);
-						if (strcmp(name, attr->name)==0) {
-							found=1;
+						if (strcmp(name, attr->name)==0)
+						{
+							found = true;
 							break;
 						}
 					}
@@ -2654,9 +2660,9 @@ transformFkeyCheckAttrs(FkConstraint *fkconstraint)
 					break;
 			}
 		}
+		ReleaseSysCache(indexTuple);
 		if (found)
 			break;		
-		indexStruct = NULL;
 	}
 	if (!found)
 		elog(ERROR, "UNIQUE constraint matching given keys for referenced table \"%s\" not found",
@@ -2681,6 +2687,7 @@ transformFkeyGetPrimaryKey(FkConstraint *fkconstraint)
 	Form_pg_attribute *pkrel_attrs;
 	List	   *indexoidlist,
 			   *indexoidscan;
+	HeapTuple	indexTuple = NULL;
 	Form_pg_index indexStruct = NULL;
 	int			i;
 
@@ -2705,17 +2712,17 @@ transformFkeyGetPrimaryKey(FkConstraint *fkconstraint)
 	foreach(indexoidscan, indexoidlist)
 	{
 		Oid		indexoid = lfirsti(indexoidscan);
-		HeapTuple	indexTuple;
 
-		indexTuple = SearchSysCacheTuple(INDEXRELID,
-										 ObjectIdGetDatum(indexoid),
-										 0, 0, 0);
+		indexTuple = SearchSysCache(INDEXRELID,
+									ObjectIdGetDatum(indexoid),
+									0, 0, 0);
 		if (!HeapTupleIsValid(indexTuple))
 			elog(ERROR, "transformFkeyGetPrimaryKey: index %u not found",
 				 indexoid);
 		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
 		if (indexStruct->indisprimary)
 			break;
+		ReleaseSysCache(indexTuple);
 		indexStruct = NULL;
 	}
 
@@ -2747,6 +2754,8 @@ transformFkeyGetPrimaryKey(FkConstraint *fkconstraint)
 		fkconstraint->pk_attrs = lappend(fkconstraint->pk_attrs, pkattr);
 	}
 
+	ReleaseSysCache(indexTuple);
+
 	heap_close(pkrel, AccessShareLock);
 }
 
@@ -2861,6 +2870,7 @@ static void
 transformColumnType(ParseState *pstate, ColumnDef *column)
 {
 	TypeName   *typename = column->typename;
+	Type		ctype = typenameType(typename->name);
 
 	/*
 	 * If the column doesn't have an explicitly specified typmod, check to
@@ -2871,7 +2881,7 @@ transformColumnType(ParseState *pstate, ColumnDef *column)
 	 */
 	if (typename->typmod == -1)
 	{
-		switch (typeTypeId(typenameType(typename->name)))
+		switch (typeTypeId(ctype))
 		{
 			case BPCHAROID:
 				/* "char" -> "char(1)" */
@@ -2891,11 +2901,13 @@ transformColumnType(ParseState *pstate, ColumnDef *column)
 	 * XXX this is a hangover from ancient Berkeley code that probably
 	 * doesn't work anymore anyway.
 	 */
-	 if (typeTypeRelid(typenameType(typename->name)) != InvalidOid)
+	 if (typeTypeRelid(ctype) != InvalidOid)
 	 {
 		 /* (Eventually add in here that the set can only
 		  * contain one element.)
 		  */
 		 typename->setof = true;
 	 }
+
+	 ReleaseSysCache(ctype);
 }