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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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26
src/backend/executor/nodeBitmapHeapscan.c
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@ -21,7 +21,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.7 2005/12/02 01:29:55 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.8 2005/12/02 20:03:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -141,9 +141,9 @@ BitmapHeapNext(BitmapHeapScanState *node)
/*
* Ignore any claimed entries past what we think is the end of the
* relation. (This is probably not necessary given that we got
* AccessShareLock before performing any of the indexscans, but
* let's be safe.)
* relation. (This is probably not necessary given that we got at
* least AccessShareLock on the table before performing any of the
* indexscans, but let's be safe.)
*/
if (tbmres->blockno >= scan->rs_nblocks)
{
@ -448,13 +448,8 @@ ExecEndBitmapHeapScan(BitmapHeapScanState *node)
/*
* close the heap relation.
*
* Currently, we do not release the AccessShareLock acquired by
* ExecInitBitmapHeapScan. This lock should be held till end of
* transaction. (There is a faction that considers this too much locking,
* however.)
*/
heap_close(relation, NoLock);
ExecCloseScanRelation(relation);
}
/* ----------------------------------------------------------------
@ -467,9 +462,6 @@ BitmapHeapScanState *
ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate)
{
BitmapHeapScanState *scanstate;
RangeTblEntry *rtentry;
Index relid;
Oid reloid;
Relation currentRelation;
/*
@ -519,13 +511,9 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate)
CXT1_printf("ExecInitBitmapHeapScan: context is %d\n", CurrentMemoryContext);
/*
* open the base relation and acquire AccessShareLock on it.
* 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);
scanstate->ss.ss_currentRelation = currentRelation;