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Add NOWAIT option to SELECT FOR UPDATE/SHARE.

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Original patch by Hans-Juergen Schoenig, revisions by Karel Zak
and Tom Lane.
This commit is contained in:
Tom Lane
2005-08-01 20:31:16 +00:00
parent ca7abcd89d
commit 2a4fad1a0e
28 changed files with 387 additions and 157 deletions
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39
src/backend/access/heap/heapam.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.195 2005/06/20 18:37:01 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.196 2005/08/01 20:31:05 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -1945,7 +1945,7 @@ simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup)
*/
HTSU_Result
heap_lock_tuple(Relation relation, HeapTuple tuple, Buffer *buffer,
CommandId cid, LockTupleMode mode)
CommandId cid, LockTupleMode mode, bool nowait)
{
HTSU_Result result;
ItemPointer tid = &(tuple->t_self);
@ -1998,7 +1998,16 @@ l3:
*/
if (!have_tuple_lock)
{
LockTuple(relation, tid, tuple_lock_type);
if (nowait)
{
if (!ConditionalLockTuple(relation, tid, tuple_lock_type))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
LockTuple(relation, tid, tuple_lock_type);
have_tuple_lock = true;
}
@ -2020,7 +2029,17 @@ l3:
else if (infomask & HEAP_XMAX_IS_MULTI)
{
/* wait for multixact to end */
MultiXactIdWait((MultiXactId) xwait);
if (nowait)
{
if (!ConditionalMultiXactIdWait((MultiXactId) xwait))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
MultiXactIdWait((MultiXactId) xwait);
LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
/*
@ -2045,7 +2064,17 @@ l3:
else
{
/* wait for regular transaction to end */
XactLockTableWait(xwait);
if (nowait)
{
if (!ConditionalXactLockTableWait(xwait))
ereport(ERROR,
(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
errmsg("could not obtain lock on row in relation \"%s\"",
RelationGetRelationName(relation))));
}
else
XactLockTableWait(xwait);
LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
/*