database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-02 09:02:37 +03:00
Code Activity

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

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

21
src/backend/executor/nodeIndexscan.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.107 2005/11/25 19:47:49 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.108 2005/12/02 20:03:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -421,12 +421,8 @@ ExecEndIndexScan(IndexScanState *node)
/*
* close the heap relation.
*
* Currently, we do not release the AccessShareLock acquired by
* ExecInitIndexScan. 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);
}
/* ----------------------------------------------------------------
@ -464,9 +460,6 @@ IndexScanState *
ExecInitIndexScan(IndexScan *node, EState *estate)
{
IndexScanState *indexstate;
RangeTblEntry *rtentry;
Index relid;
Oid reloid;
Relation currentRelation;
/*
@ -551,13 +544,9 @@ ExecInitIndexScan(IndexScan *node, EState *estate)
}
/*
* 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);
indexstate->ss.ss_currentRelation = currentRelation;
indexstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */
@ -570,7 +559,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate)
/*
* open the index relation and initialize relation and scan descriptors.
* Note we acquire no locks here; the index machinery does its own locks
* and unlocks. (We rely on having AccessShareLock on the parent table to
* and unlocks. (We rely on having a lock on the parent table to
* ensure the index won't go away!)
*/
indexstate->iss_RelationDesc = index_open(node->indexid);