*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.218 2006/07/31 20:08:59 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.219 2006/08/18 16:09:08 tgl Exp $
*
*
* INTERFACE ROUTINES
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/relcache.h"
+#include "utils/syscache.h"
static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf,
}
/* ----------------
- * conditional_relation_open - open with option not to wait
+ * try_relation_open - open any relation by relation OID
*
- * As above, but if nowait is true, then throw an error rather than
- * waiting when the lock is not immediately obtainable.
+ * Same as relation_open, except return NULL instead of failing
+ * if the relation does not exist.
* ----------------
*/
Relation
-conditional_relation_open(Oid relationId, LOCKMODE lockmode, bool nowait)
+try_relation_open(Oid relationId, LOCKMODE lockmode)
+{
+ Relation r;
+
+ Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
+
+ /* Get the lock first */
+ if (lockmode != NoLock)
+ LockRelationOid(relationId, lockmode);
+
+ /*
+ * Now that we have the lock, probe to see if the relation really
+ * exists or not.
+ */
+ if (!SearchSysCacheExists(RELOID,
+ ObjectIdGetDatum(relationId),
+ 0, 0, 0))
+ {
+ /* Release useless lock */
+ if (lockmode != NoLock)
+ UnlockRelationOid(relationId, lockmode);
+
+ return NULL;
+ }
+
+ /* Should be safe to do a relcache load */
+ r = RelationIdGetRelation(relationId);
+
+ if (!RelationIsValid(r))
+ elog(ERROR, "could not open relation with OID %u", relationId);
+
+ return r;
+}
+
+/* ----------------
+ * relation_open_nowait - open but don't wait for lock
+ *
+ * Same as relation_open, except throw an error instead of waiting
+ * when the requested lock is not immediately obtainable.
+ * ----------------
+ */
+Relation
+relation_open_nowait(Oid relationId, LOCKMODE lockmode)
{
Relation r;
/* Get the lock before trying to open the relcache entry */
if (lockmode != NoLock)
{
- if (nowait)
+ if (!ConditionalLockRelationOid(relationId, lockmode))
{
- if (!ConditionalLockRelationOid(relationId, lockmode))
- {
- /* try to throw error by name; relation could be deleted... */
- char *relname = get_rel_name(relationId);
-
- if (relname)
- ereport(ERROR,
- (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
- errmsg("could not obtain lock on relation \"%s\"",
- relname)));
- else
- ereport(ERROR,
- (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
- errmsg("could not obtain lock on relation with OID %u",
- relationId)));
- }
+ /* try to throw error by name; relation could be deleted... */
+ char *relname = get_rel_name(relationId);
+
+ if (relname)
+ ereport(ERROR,
+ (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+ errmsg("could not obtain lock on relation \"%s\"",
+ relname)));
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+ errmsg("could not obtain lock on relation with OID %u",
+ relationId)));
}
- else
- LockRelationOid(relationId, lockmode);
}
/* The relcache does all the real work... */
/* ----------------
* relation_openrv - open any relation specified by a RangeVar
*
- * As above, but the relation is specified by a RangeVar.
+ * Same as relation_open, but the relation is specified by a RangeVar.
* ----------------
*/
Relation
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.96 2006/07/14 14:52:18 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.97 2006/08/18 16:09:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
CHECK_FOR_INTERRUPTS();
/*
- * Race condition -- if the pg_class tuple has gone away since the last
- * time we saw it, we don't need to process it.
+ * Open the relation, getting only a read lock on it. If the rel has
+ * been dropped since we last saw it, we don't need to process it.
*/
- if (!SearchSysCacheExists(RELOID,
- ObjectIdGetDatum(relid),
- 0, 0, 0))
+ onerel = try_relation_open(relid, AccessShareLock);
+ if (!onerel)
return;
/*
- * Open the class, getting only a read lock on it, and check permissions.
- * Permissions check should match vacuum's check!
+ * Check permissions --- this should match vacuum's check!
*/
- onerel = relation_open(relid, AccessShareLock);
-
if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
(pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
{
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.152 2006/07/31 20:09:00 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.153 2006/08/18 16:09:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/* Check for user-requested abort. */
CHECK_FOR_INTERRUPTS();
+ /*
+ * We grab exclusive access to the target rel and index for the duration
+ * of the transaction. (This is redundant for the single-transaction
+ * case, since cluster() already did it.) The index lock is taken inside
+ * check_index_is_clusterable.
+ */
+ OldHeap = try_relation_open(rvtc->tableOid, AccessExclusiveLock);
+
+ /* If the table has gone away, we can skip processing it */
+ if (!OldHeap)
+ return;
+
/*
* Since we may open a new transaction for each relation, we have to check
* that the relation still is what we think it is.
HeapTuple tuple;
Form_pg_index indexForm;
+ /* Check that the user still owns the relation */
+ if (!pg_class_ownercheck(rvtc->tableOid, GetUserId()))
+ {
+ relation_close(OldHeap, AccessExclusiveLock);
+ return;
+ }
+
/*
- * Check if the relation and index still exist before opening them
+ * Check that the index still exists
*/
if (!SearchSysCacheExists(RELOID,
- ObjectIdGetDatum(rvtc->tableOid),
- 0, 0, 0) ||
- !SearchSysCacheExists(RELOID,
ObjectIdGetDatum(rvtc->indexOid),
0, 0, 0))
+ {
+ relation_close(OldHeap, AccessExclusiveLock);
return;
-
- /* Check that the user still owns the relation */
- if (!pg_class_ownercheck(rvtc->tableOid, GetUserId()))
- return;
+ }
/*
* Check that the index is still the one with indisclustered set.
tuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(rvtc->indexOid),
0, 0, 0);
- if (!HeapTupleIsValid(tuple))
- return; /* could have gone away... */
+ if (!HeapTupleIsValid(tuple)) /* probably can't happen */
+ {
+ relation_close(OldHeap, AccessExclusiveLock);
+ return;
+ }
indexForm = (Form_pg_index) GETSTRUCT(tuple);
if (!indexForm->indisclustered)
{
ReleaseSysCache(tuple);
+ relation_close(OldHeap, AccessExclusiveLock);
return;
}
ReleaseSysCache(tuple);
}
- /*
- * We grab exclusive access to the target rel and index for the duration
- * of the transaction. (This is redundant for the single- transaction
- * case, since cluster() already did it.) The index lock is taken inside
- * check_index_is_clusterable.
- */
- OldHeap = heap_open(rvtc->tableOid, AccessExclusiveLock);
-
/* Check index is valid to cluster on */
check_index_is_clusterable(OldHeap, rvtc->indexOid, recheck);
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/lockcmds.c,v 1.14 2006/03/05 15:58:24 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/lockcmds.c,v 1.15 2006/08/18 16:09:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
aclcheck_error(aclresult, ACL_KIND_CLASS,
get_rel_name(reloid));
- rel = conditional_relation_open(reloid, lockstmt->mode, lockstmt->nowait);
+ if (lockstmt->nowait)
+ rel = relation_open_nowait(reloid, lockstmt->mode);
+ else
+ rel = relation_open(reloid, lockstmt->mode);
/* Currently, we only allow plain tables to be locked */
if (rel->rd_rel->relkind != RELKIND_RELATION)
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.337 2006/07/31 20:09:00 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.338 2006/08/18 16:09:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
MyProc->inVacuum = true;
}
- /*
- * Tell the cache replacement strategy that vacuum is causing all
- * following IO
- */
- StrategyHintVacuum(true);
-
/*
* Check for user-requested abort. Note we want this to be inside a
* transaction, so xact.c doesn't issue useless WARNING.
*/
CHECK_FOR_INTERRUPTS();
- /*
- * Race condition -- if the pg_class tuple has gone away since the last
- * time we saw it, we don't need to vacuum it.
- */
- if (!SearchSysCacheExists(RELOID,
- ObjectIdGetDatum(relid),
- 0, 0, 0))
- {
- StrategyHintVacuum(false);
- CommitTransactionCommand();
- return;
- }
-
/*
* Determine the type of lock we want --- hard exclusive lock for a FULL
* vacuum, but just ShareUpdateExclusiveLock for concurrent vacuum. Either
lmode = vacstmt->full ? AccessExclusiveLock : ShareUpdateExclusiveLock;
/*
- * Open the class, get an appropriate lock on it, and check permissions.
+ * Open the relation and get the appropriate lock on it.
+ *
+ * There's a race condition here: the rel may have gone away since
+ * the last time we saw it. If so, we don't need to vacuum it.
+ */
+ onerel = try_relation_open(relid, lmode);
+
+ if (!onerel)
+ {
+ CommitTransactionCommand();
+ return;
+ }
+
+ /*
+ * Check permissions.
*
* We allow the user to vacuum a table if he is superuser, the table
* owner, or the database owner (but in the latter case, only if it's not
* Note we choose to treat permissions failure as a WARNING and keep
* trying to vacuum the rest of the DB --- is this appropriate?
*/
- onerel = relation_open(relid, lmode);
-
if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
(pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
{
(errmsg("skipping \"%s\" --- only table or database owner can vacuum it",
RelationGetRelationName(onerel))));
relation_close(onerel, lmode);
- StrategyHintVacuum(false);
CommitTransactionCommand();
return;
}
(errmsg("skipping \"%s\" --- cannot vacuum indexes, views, or special system tables",
RelationGetRelationName(onerel))));
relation_close(onerel, lmode);
- StrategyHintVacuum(false);
CommitTransactionCommand();
return;
}
if (isOtherTempNamespace(RelationGetNamespace(onerel)))
{
relation_close(onerel, lmode);
- StrategyHintVacuum(false);
CommitTransactionCommand();
return; /* assume no long-lived data in temp tables */
}
*/
toast_relid = onerel->rd_rel->reltoastrelid;
+ /*
+ * Tell the cache replacement strategy that vacuum is causing all
+ * following IO
+ */
+ StrategyHintVacuum(true);
+
/*
* Do the actual work --- either FULL or "lazy" vacuum
*/
else
lazy_vacuum_rel(onerel, vacstmt);
+ StrategyHintVacuum(false);
+
/* all done with this class, but hold lock until commit */
relation_close(onerel, NoLock);
/*
* Complete the transaction and free all temporary memory used.
*/
- StrategyHintVacuum(false);
CommitTransactionCommand();
/*
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.86 2006/07/31 20:09:05 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.87 2006/08/18 16:09:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* UnlockRelationId
*
- * Note: we don't supply UnlockRelationOid since it's normally easy for
- * callers to provide the LockRelId info from a relcache entry.
+ * Unlock, given a LockRelId. This is preferred over UnlockRelationOid
+ * for speed reasons.
*/
void
UnlockRelationId(LockRelId *relid, LOCKMODE lockmode)
LockRelease(&tag, lockmode, false);
}
+/*
+ * UnlockRelationOid
+ *
+ * Unlock, given only a relation Oid. Use UnlockRelationId if you can.
+ */
+void
+UnlockRelationOid(Oid relid, LOCKMODE lockmode)
+{
+ LOCKTAG tag;
+
+ SetLocktagRelationOid(&tag, relid);
+
+ LockRelease(&tag, lockmode, false);
+}
+
/*
* LockRelation
*
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.114 2006/07/03 22:45:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.115 2006/08/18 16:09:10 tgl Exp $
*
*-------------------------------------------------------------------------
*/
} LockTupleMode;
extern Relation relation_open(Oid relationId, LOCKMODE lockmode);
-extern Relation conditional_relation_open(Oid relationId, LOCKMODE lockmode, bool nowait);
+extern Relation try_relation_open(Oid relationId, LOCKMODE lockmode);
+extern Relation relation_open_nowait(Oid relationId, LOCKMODE lockmode);
extern Relation relation_openrv(const RangeVar *relation, LOCKMODE lockmode);
extern void relation_close(Relation relation, LOCKMODE lockmode);
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.55 2006/07/31 20:09:05 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.56 2006/08/18 16:09:13 tgl Exp $
*
*-------------------------------------------------------------------------
*/
extern void LockRelationOid(Oid relid, LOCKMODE lockmode);
extern bool ConditionalLockRelationOid(Oid relid, LOCKMODE lockmode);
extern void UnlockRelationId(LockRelId *relid, LOCKMODE lockmode);
+extern void UnlockRelationOid(Oid relid, LOCKMODE lockmode);
extern void LockRelation(Relation relation, LOCKMODE lockmode);
extern bool ConditionalLockRelation(Relation relation, LOCKMODE lockmode);
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