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Change SearchSysCache coding conventions so that a reference count is

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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.
This commit is contained in:
Tom Lane
2000-11-16 22:30:52 +00:00
parent cff23842a4
commit a933ee38bb
95 changed files with 2672 additions and 2314 deletions
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35
src/backend/commands/async.c
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.70 2000/10/03 03:11:13 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/async.c,v 1.71 2000/11/16 22:30:18 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -193,9 +193,7 @@ void
Async_Listen(char *relname, int pid)
{
Relation lRel;
TupleDesc tdesc;
HeapTuple tuple,
newtup;
HeapTuple tuple;
Datum values[Natts_pg_listener];
char nulls[Natts_pg_listener];
int i;
@@ -205,13 +203,12 @@ Async_Listen(char *relname, int pid)
elog(DEBUG, "Async_Listen: %s", relname);
lRel = heap_openr(ListenerRelationName, AccessExclusiveLock);
tdesc = RelationGetDescr(lRel);
/* Detect whether we are already listening on this relname */
tuple = SearchSysCacheTuple(LISTENREL, Int32GetDatum(pid),
PointerGetDatum(relname),
0, 0);
if (tuple != NULL)
if (SearchSysCacheExists(LISTENREL,
Int32GetDatum(pid),
PointerGetDatum(relname),
0, 0))
{
/* No need to scan the rest of the table */
heap_close(lRel, AccessExclusiveLock);
@@ -235,18 +232,18 @@ Async_Listen(char *relname, int pid)
values[i++] = (Datum) 0; /* no notifies pending */
tupDesc = lRel->rd_att;
newtup = heap_formtuple(tupDesc, values, nulls);
heap_insert(lRel, newtup);
tuple = heap_formtuple(tupDesc, values, nulls);
heap_insert(lRel, tuple);
if (RelationGetForm(lRel)->relhasindex)
{
Relation idescs[Num_pg_listener_indices];
CatalogOpenIndices(Num_pg_listener_indices, Name_pg_listener_indices, idescs);
CatalogIndexInsert(idescs, Num_pg_listener_indices, lRel, newtup);
CatalogIndexInsert(idescs, Num_pg_listener_indices, lRel, tuple);
CatalogCloseIndices(Num_pg_listener_indices, idescs);
}
heap_freetuple(newtup);
heap_freetuple(tuple);
heap_close(lRel, AccessExclusiveLock);
@@ -296,11 +293,15 @@ Async_Unlisten(char *relname, int pid)
lRel = heap_openr(ListenerRelationName, AccessExclusiveLock);
/* Note we assume there can be only one matching tuple. */
lTuple = SearchSysCacheTuple(LISTENREL, Int32GetDatum(pid),
PointerGetDatum(relname),
0, 0);
if (lTuple != NULL)
lTuple = SearchSysCache(LISTENREL,
Int32GetDatum(pid),
PointerGetDatum(relname),
0, 0);
if (HeapTupleIsValid(lTuple))
{
heap_delete(lRel, &lTuple->t_self, NULL);
ReleaseSysCache(lTuple);
}
heap_close(lRel, AccessExclusiveLock);
/*