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Adjust nodeBitmapIndexscan.c to not keep the index open across calls,

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but just to open and close it during MultiExecBitmapIndexScan.  This
avoids acquiring duplicate resources (eg, multiple locks on the same
relation) in a tree with many bitmap scans.  Also, don't bother to
lock the parent heap at all here, since we must be underneath a
BitmapHeapScan node that will be holding a suitable lock.
REL8_1_STABLE
Tom Lane 21 years ago
parent 8403741796
commit 186655e9a5
2 changed files with 30 additions and 88 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 112
      src/backend/executor/nodeBitmapIndexscan.c
  2. 6
      src/include/nodes/execnodes.h

112
src/backend/executor/nodeBitmapIndexscan.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.5 2005/04/24 17:32:46 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.6 2005/04/24 18:16:38 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -41,6 +41,8 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
{
#define MAX_TIDS 1024
TIDBitmap *tbm;
Oid indxid;
Relation indexRelation;
IndexScanDesc scandesc;
ItemPointerData tids[MAX_TIDS];
int32 ntids;
@ -58,9 +60,22 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
ExecReScan((PlanState *) node, NULL);
/*
* extract necessary information from index scan node
* We do not open or lock the base relation here. We assume that an
* ancestor BitmapHeapScan node is holding AccessShareLock on the
* heap relation throughout the execution of the plan tree.
*/
scandesc = node->biss_ScanDesc;
/*
* 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.
*/
indxid = ((BitmapIndexScan *) node->ss.ps.plan)->indxid;
indexRelation = index_open(indxid);
scandesc = index_beginscan_multi(indexRelation,
node->ss.ps.state->es_snapshot,
node->biss_NumScanKeys,
node->biss_ScanKeys);
/*
* Prepare the result bitmap. Normally we just create a new one to pass
@ -98,6 +113,12 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
CHECK_FOR_INTERRUPTS();
}
/*
* close the index relation
*/
index_endscan(scandesc);
index_close(indexRelation);
/* must provide our own instrumentation support */
if (node->ss.ps.instrument)
InstrStopNodeMulti(node->ss.ps.instrument, nTuples);
@ -109,11 +130,7 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
* ExecBitmapIndexReScan(node)
*
* Recalculates the value of the scan keys whose value depends on
* information known at runtime and rescans the indexed relation.
* Updating the scan key was formerly done separately in
* ExecUpdateIndexScanKeys. Integrating it into ReScan makes
* rescans of indices and relations/general streams more uniform.
*
* information known at runtime.
* ----------------------------------------------------------------
*/
void
@ -121,12 +138,10 @@ ExecBitmapIndexReScan(BitmapIndexScanState *node, ExprContext *exprCtxt)
{
ExprContext *econtext;
ExprState **runtimeKeyInfo;
Index scanrelid;
econtext = node->biss_RuntimeContext; /* context for runtime
* keys */
runtimeKeyInfo = node->biss_RuntimeKeyInfo;
scanrelid = ((BitmapIndexScan *) node->ss.ps.plan)->scan.scanrelid;
if (econtext)
{
@ -194,8 +209,6 @@ ExecBitmapIndexReScan(BitmapIndexScanState *node, ExprContext *exprCtxt)
node->biss_RuntimeKeysReady = true;
}
index_rescan(node->biss_ScanDesc, node->biss_ScanKeys);
}
/* ----------------------------------------------------------------
@ -205,13 +218,6 @@ ExecBitmapIndexReScan(BitmapIndexScanState *node, ExprContext *exprCtxt)
void
ExecEndBitmapIndexScan(BitmapIndexScanState *node)
{
Relation relation;
/*
* extract information from the node
*/
relation = node->ss.ss_currentRelation;
/*
* Free the exprcontext ... now dead code, see ExecFreeExprContext
*/
@ -219,44 +225,12 @@ ExecEndBitmapIndexScan(BitmapIndexScanState *node)
if (node->biss_RuntimeContext)
FreeExprContext(node->biss_RuntimeContext);
#endif
/*
* close the index relation
*/
if (node->biss_ScanDesc != NULL)
index_endscan(node->biss_ScanDesc);
if (node->biss_RelationDesc != NULL)
index_close(node->biss_RelationDesc);
/*
* close the heap relation.
*
* Currently, we do not release the AccessShareLock acquired by
* ExecInitBitmapIndexScan. This lock should be held till end of
* transaction. (There is a faction that considers this too much
* locking, however.)
*/
heap_close(relation, NoLock);
}
/* ----------------------------------------------------------------
* ExecInitBitmapIndexScan
*
* Initializes the index scan's state information, creates
* scan keys, and opens the base and index relations.
*
* Note: index scans have 2 sets of state information because
* we have to keep track of the base relation and the
* index relations.
*
* old comments
* Creates the run-time state information for the node and
* sets the relation id to contain relevant descriptors.
*
* Parameters:
* node: BitmapIndexNode node produced by the planner.
* estate: the execution state initialized in InitPlan.
* Initializes the index scan's state information.
* ----------------------------------------------------------------
*/
BitmapIndexScanState *
@ -265,10 +239,6 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate)
BitmapIndexScanState *indexstate;
ExprState **runtimeKeyInfo;
bool have_runtime_keys;
RangeTblEntry *rtentry;
Index relid;
Oid reloid;
Relation currentRelation;
/*
* create state structure
@ -306,8 +276,6 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate)
indexstate->biss_RuntimeKeyInfo = NULL;
indexstate->biss_RuntimeContext = NULL;
indexstate->biss_RuntimeKeysReady = false;
indexstate->biss_RelationDesc = NULL;
indexstate->biss_ScanDesc = NULL;
CXT1_printf("ExecInitBitmapIndexScan: context is %d\n", CurrentMemoryContext);
@ -459,7 +427,6 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate)
runtimeKeyInfo = run_keys;
}
/*
* If all of our keys have the form (var op const), then we have no
* runtime keys so we store NULL in the runtime key info. Otherwise
@ -489,30 +456,9 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate)
pfree(runtimeKeyInfo);
}
/*
* open the base relation and acquire AccessShareLock on it.
*/
relid = node->scan.scanrelid;
rtentry = rt_fetch(relid, estate->es_range_table);
reloid = rtentry->relid;
currentRelation = heap_open(reloid, AccessShareLock);
indexstate->ss.ss_currentRelation = currentRelation;
indexstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */
/*
* 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 ensure the index won't go away!)
*/
indexstate->biss_RelationDesc = index_open(node->indxid);
indexstate->biss_ScanDesc =
index_beginscan_multi(indexstate->biss_RelationDesc,
estate->es_snapshot,
indexstate->biss_NumScanKeys,
indexstate->biss_ScanKeys);
/* We don't keep the table or index open across calls */
indexstate->ss.ss_currentRelation = NULL;
indexstate->ss.ss_currentScanDesc = NULL;
/*
* all done.

6
src/include/nodes/execnodes.h
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.127 2005/04/20 15:48:36 tgl Exp $
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.128 2005/04/24 18:16:38 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -908,8 +908,6 @@ typedef struct IndexScanState
* that will be evaluated at runtime
* RuntimeContext expr context for evaling runtime Skeys
* RuntimeKeysReady true if runtime Skeys have been computed
* RelationDesc relation descriptor
* ScanDesc scan descriptor
* ----------------
*/
typedef struct BitmapIndexScanState
@ -921,8 +919,6 @@ typedef struct BitmapIndexScanState
ExprState **biss_RuntimeKeyInfo;
ExprContext *biss_RuntimeContext;
bool biss_RuntimeKeysReady;
Relation biss_RelationDesc;
IndexScanDesc biss_ScanDesc;
} BitmapIndexScanState;
/* ----------------

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