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Adjust scan plan nodes to avoid getting an extra AccessShareLock on a

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relation if it's already been locked by execMain.c as either a result
relation or a FOR UPDATE/SHARE relation.  This avoids an extra trip to
the shared lock manager state.  Per my suggestion yesterday.
This commit is contained in:
Tom Lane
2005-12-02 20:03:42 +00:00
parent 5ab2598875
commit d780f07ac1
9 changed files with 135 additions and 92 deletions
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21
src/backend/executor/nodeTidscan.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.45 2005/11/26 22:14:56 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeTidscan.c,v 1.46 2005/12/02 20:03:41 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -421,12 +421,8 @@ ExecEndTidScan(TidScanState *node)
/*
* close the heap relation.
*
* Currently, we do not release the AccessShareLock acquired by
* ExecInitTidScan. This lock should be held till end of transaction.
* (There is a faction that considers this too much locking, however.)
*/
heap_close(node->ss.ss_currentRelation, NoLock);
ExecCloseScanRelation(node->ss.ss_currentRelation);
}
/* ----------------------------------------------------------------
@ -472,9 +468,6 @@ TidScanState *
ExecInitTidScan(TidScan *node, EState *estate)
{
TidScanState *tidstate;
RangeTblEntry *rtentry;
Oid relid;
Oid reloid;
Relation currentRelation;
/*
@ -521,15 +514,9 @@ ExecInitTidScan(TidScan *node, EState *estate)
tidstate->tss_TidPtr = -1;
/*
* open the base relation
*
* We acquire AccessShareLock for the duration of the scan.
* open the base relation and acquire appropriate lock on it.
*/
relid = node->scan.scanrelid;
rtentry = rt_fetch(relid, estate->es_range_table);
reloid = rtentry->relid;
currentRelation = heap_open(reloid, AccessShareLock);
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid);
tidstate->ss.ss_currentRelation = currentRelation;
tidstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */