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, 30 insertions, 26 deletions

diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 818bc6ab082..63e4d9b46d2 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.81 2000/11/10 09:38:21 inoue Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.82 2000/11/16 22:30:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -324,12 +324,15 @@ scalarltsel(PG_FUNCTION_ARGS)
 		 * Get left and right datatypes of the operator so we know what
 		 * type the constant is.
 		 */
-		oprtuple = get_operator_tuple(opid);
+		oprtuple = SearchSysCache(OPEROID,
+								  ObjectIdGetDatum(opid),
+								  0, 0, 0);
 		if (!HeapTupleIsValid(oprtuple))
 			elog(ERROR, "scalarltsel: no tuple for operator %u", opid);
 		ltype = ((Form_pg_operator) GETSTRUCT(oprtuple))->oprleft;
 		rtype = ((Form_pg_operator) GETSTRUCT(oprtuple))->oprright;
 		contype = (flag & SEL_RIGHT) ? rtype : ltype;
+		ReleaseSysCache(oprtuple);
 
 		/* Now get info and stats about the attribute */
 		getattproperties(relid, attno,
@@ -482,11 +485,14 @@ patternsel(PG_FUNCTION_ARGS, Pattern_Type ptype)
 		 * Get left and right datatypes of the operator so we know what
 		 * type the attribute is.
 		 */
-		oprtuple = get_operator_tuple(opid);
+		oprtuple = SearchSysCache(OPEROID,
+								  ObjectIdGetDatum(opid),
+								  0, 0, 0);
 		if (!HeapTupleIsValid(oprtuple))
 			elog(ERROR, "patternsel: no tuple for operator %u", opid);
 		ltype = ((Form_pg_operator) GETSTRUCT(oprtuple))->oprleft;
 		rtype = ((Form_pg_operator) GETSTRUCT(oprtuple))->oprright;
+		ReleaseSysCache(oprtuple);
 
 		/* the right-hand const is type text for all supported operators */
 		Assert(rtype == TEXTOID);
@@ -1189,10 +1195,10 @@ getattproperties(Oid relid, AttrNumber attnum,
 	HeapTuple	atp;
 	Form_pg_attribute att_tup;
 
-	atp = SearchSysCacheTuple(ATTNUM,
-							  ObjectIdGetDatum(relid),
-							  Int16GetDatum(attnum),
-							  0, 0);
+	atp = SearchSysCache(ATTNUM,
+						 ObjectIdGetDatum(relid),
+						 Int16GetDatum(attnum),
+						 0, 0);
 	if (!HeapTupleIsValid(atp))
 		elog(ERROR, "getattproperties: no attribute tuple %u %d",
 			 relid, (int) attnum);
@@ -1202,6 +1208,8 @@ getattproperties(Oid relid, AttrNumber attnum,
 	*typlen = att_tup->attlen;
 	*typbyval = att_tup->attbyval;
 	*typmod = att_tup->atttypmod;
+
+	ReleaseSysCache(atp);
 }
 
 /*
@@ -1250,11 +1258,10 @@ getattstatistics(Oid relid,
 	 * have at hand!  (For example, we might have a '>' operator rather
 	 * than the '<' operator that will appear in staop.)
 	 */
-	tuple = SearchSysCacheTupleCopy(STATRELID,
-								ObjectIdGetDatum(relid),
-								Int16GetDatum((int16) attnum),
-								0,
-								0);
+	tuple = SearchSysCache(STATRELID,
+						   ObjectIdGetDatum(relid),
+						   Int16GetDatum((int16) attnum),
+						   0, 0);
 	if (!HeapTupleIsValid(tuple))
 	{
 		/* no such stats entry */
@@ -1267,14 +1274,15 @@ getattstatistics(Oid relid,
 		*commonfrac = ((Form_pg_statistic) GETSTRUCT(tuple))->stacommonfrac;
 
 	/* Get the type input proc for the column datatype */
-	typeTuple = SearchSysCacheTuple(TYPEOID,
-									ObjectIdGetDatum(typid),
-									0, 0, 0);
+	typeTuple = SearchSysCache(TYPEOID,
+							   ObjectIdGetDatum(typid),
+							   0, 0, 0);
 	if (!HeapTupleIsValid(typeTuple))
 		elog(ERROR, "getattstatistics: Cache lookup failed for type %u",
 			 typid);
 	fmgr_info(((Form_pg_type) GETSTRUCT(typeTuple))->typinput, &inputproc);
 	typelem = ((Form_pg_type) GETSTRUCT(typeTuple))->typelem;
+	ReleaseSysCache(typeTuple);
 
 	/*
 	 * Values are variable-length fields, so cannot access as struct
@@ -1351,7 +1359,8 @@ getattstatistics(Oid relid,
 			pfree(strval);
 		}
 	}
-	heap_freetuple(tuple);
+
+	ReleaseSysCache(tuple);
 
 	return true;
 }
@@ -1966,16 +1975,11 @@ string_lessthan(const char *str1, const char *str2, Oid datatype)
 static Oid
 find_operator(const char *opname, Oid datatype)
 {
-	HeapTuple	optup;
-
-	optup = SearchSysCacheTuple(OPERNAME,
-								PointerGetDatum(opname),
-								ObjectIdGetDatum(datatype),
-								ObjectIdGetDatum(datatype),
-								CharGetDatum('b'));
-	if (!HeapTupleIsValid(optup))
-		return InvalidOid;
-	return optup->t_data->t_oid;
+	return GetSysCacheOid(OPERNAME,
+						  PointerGetDatum(opname),
+						  ObjectIdGetDatum(datatype),
+						  ObjectIdGetDatum(datatype),
+						  CharGetDatum('b'));
 }
 
 /*