463 lines
11 KiB
C
463 lines
11 KiB
C
/*-------------------------------------------------------------------------
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*
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* execAmi.c
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* miscellaneous executor access method routines
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: execAmi.c,v 1.49 2000/07/12 02:37:00 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* INTERFACE ROUTINES
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*
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* ExecOpenScanR \ / amopen
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* ExecBeginScan \ / ambeginscan
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* ExecCloseR \ / amclose
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* ExecInsert \ executor interface / aminsert
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* ExecReScanR / to access methods \ amrescan
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* ExecMarkPos / \ ammarkpos
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* ExecRestrPos / \ amrestpos
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*/
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#include "postgres.h"
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#include "access/genam.h"
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#include "access/heapam.h"
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#include "catalog/heap.h"
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#include "executor/execdebug.h"
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#include "executor/nodeAgg.h"
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#include "executor/nodeAppend.h"
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#include "executor/nodeGroup.h"
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#include "executor/nodeGroup.h"
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#include "executor/nodeHash.h"
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#include "executor/nodeHashjoin.h"
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#include "executor/nodeIndexscan.h"
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#include "executor/nodeTidscan.h"
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#include "executor/nodeMaterial.h"
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#include "executor/nodeMergejoin.h"
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#include "executor/nodeNestloop.h"
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#include "executor/nodeResult.h"
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#include "executor/nodeSeqscan.h"
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#include "executor/nodeSort.h"
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#include "executor/nodeSubplan.h"
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#include "executor/nodeUnique.h"
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static Pointer ExecBeginScan(Relation relation, int nkeys, ScanKey skeys,
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bool isindex, ScanDirection dir, Snapshot snapshot);
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/* ----------------------------------------------------------------
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* ExecOpenScanR
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*
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* old comments:
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* Parameters:
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* relation -- relation to be opened and scanned.
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* nkeys -- number of keys
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* skeys -- keys to restrict scanning
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* isindex -- if this is true, the relation is the relid of
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* an index relation, else it is an index into the
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* range table.
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* Returns the relation as(relDesc scanDesc)
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* If this structure is changed, need to modify the access macros
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* defined in execInt.h.
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* ----------------------------------------------------------------
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*/
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void
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ExecOpenScanR(Oid relOid,
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int nkeys,
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ScanKey skeys,
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bool isindex,
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ScanDirection dir,
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Snapshot snapshot,
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Relation *returnRelation, /* return */
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Pointer *returnScanDesc) /* return */
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{
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Relation relation;
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Pointer scanDesc;
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/* ----------------
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* note: scanDesc returned by ExecBeginScan can be either
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* a HeapScanDesc or an IndexScanDesc so for now we
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* make it a Pointer. There should be a better scan
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* abstraction someday -cim 9/9/89
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* ----------------
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*/
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/* ----------------
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* open the relation with the correct call depending
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* on whether this is a heap relation or an index relation.
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*
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* Do not lock the rel here; beginscan will acquire AccessShareLock.
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* ----------------
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*/
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if (isindex)
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relation = index_open(relOid);
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else
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relation = heap_open(relOid, NoLock);
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if (relation == NULL)
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elog(ERROR, "ExecOpenScanR: failed to open relation %u", relOid);
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scanDesc = ExecBeginScan(relation,
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nkeys,
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skeys,
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isindex,
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dir,
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snapshot);
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if (returnRelation != NULL)
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*returnRelation = relation;
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if (scanDesc != NULL)
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*returnScanDesc = scanDesc;
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}
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/* ----------------------------------------------------------------
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* ExecBeginScan
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*
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* beginscans a relation in current direction.
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*
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* XXX fix parameters to AMbeginscan (and btbeginscan)
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* currently we need to pass a flag stating whether
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* or not the scan should begin at an endpoint of
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* the relation.. Right now we always pass false
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* -cim 9/14/89
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* ----------------------------------------------------------------
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*/
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static Pointer
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ExecBeginScan(Relation relation,
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int nkeys,
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ScanKey skeys,
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bool isindex,
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ScanDirection dir,
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Snapshot snapshot)
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{
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Pointer scanDesc;
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scanDesc = NULL;
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/* ----------------
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* open the appropriate type of scan.
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*
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* Note: ambeginscan()'s second arg is a boolean indicating
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* that the scan should be done in reverse.. That is,
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* if you pass it true, then the scan is backward.
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* ----------------
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*/
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if (isindex)
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{
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scanDesc = (Pointer) index_beginscan(relation,
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false, /* see above comment */
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nkeys,
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skeys);
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}
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else
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{
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scanDesc = (Pointer) heap_beginscan(relation,
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ScanDirectionIsBackward(dir),
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snapshot,
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nkeys,
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skeys);
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}
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if (scanDesc == NULL)
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elog(DEBUG, "ExecBeginScan: scanDesc = NULL, heap_beginscan failed.");
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return scanDesc;
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}
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/* ----------------------------------------------------------------
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* ExecCloseR
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*
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* closes the relation and scan descriptor for a scan node.
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* Also closes index relations and scans for index scans.
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* ----------------------------------------------------------------
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*/
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void
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ExecCloseR(Plan *node)
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{
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CommonScanState *state;
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Relation relation;
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HeapScanDesc scanDesc;
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/* ----------------
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* shut down the heap scan and close the heap relation
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* ----------------
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*/
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switch (nodeTag(node))
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{
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case T_SeqScan:
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state = ((SeqScan *) node)->scanstate;
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break;
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case T_IndexScan:
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state = ((IndexScan *) node)->scan.scanstate;
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break;
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case T_TidScan:
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state = ((TidScan *) node)->scan.scanstate;
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break;
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default:
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elog(DEBUG, "ExecCloseR: not a scan node!");
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return;
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}
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relation = state->css_currentRelation;
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scanDesc = state->css_currentScanDesc;
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if (scanDesc != NULL)
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heap_endscan(scanDesc);
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/*
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* endscan released AccessShareLock acquired by beginscan. If we are
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* holding any stronger locks on the rel, they should be held till end
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* of xact. Therefore, we need only close the rel and not release
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* locks.
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*/
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if (relation != NULL)
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heap_close(relation, NoLock);
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/* ----------------
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* if this is an index scan then we have to take care
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* of the index relations as well..
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* ----------------
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*/
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if (IsA(node, IndexScan))
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{
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IndexScan *iscan = (IndexScan *) node;
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IndexScanState *indexstate = iscan->indxstate;
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int numIndices;
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RelationPtr indexRelationDescs;
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IndexScanDescPtr indexScanDescs;
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int i;
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numIndices = indexstate->iss_NumIndices;
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indexRelationDescs = indexstate->iss_RelationDescs;
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indexScanDescs = indexstate->iss_ScanDescs;
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for (i = 0; i < numIndices; i++)
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{
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/* ----------------
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* shut down each of the scans and
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* close each of the index relations
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* ----------------
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*/
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if (indexScanDescs[i] != NULL)
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index_endscan(indexScanDescs[i]);
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if (indexRelationDescs[i] != NULL)
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index_close(indexRelationDescs[i]);
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}
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}
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}
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/* ----------------------------------------------------------------
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* ExecReScan
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*
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* XXX this should be extended to cope with all the node types..
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*
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* takes the new expression context as an argument, so that
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* index scans needn't have their scan keys updated separately
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* - marcel 09/20/94
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* ----------------------------------------------------------------
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*/
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void
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ExecReScan(Plan *node, ExprContext *exprCtxt, Plan *parent)
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{
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if (node->chgParam != NULL) /* Wow! */
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{
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List *lst;
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foreach(lst, node->initPlan)
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{
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Plan *splan = ((SubPlan *) lfirst(lst))->plan;
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if (splan->extParam != NULL) /* don't care about child
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* locParam */
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SetChangedParamList(splan, node->chgParam);
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if (splan->chgParam != NULL)
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ExecReScanSetParamPlan((SubPlan *) lfirst(lst), node);
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}
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foreach(lst, node->subPlan)
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{
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Plan *splan = ((SubPlan *) lfirst(lst))->plan;
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if (splan->extParam != NULL)
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SetChangedParamList(splan, node->chgParam);
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}
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/* Well. Now set chgParam for left/right trees. */
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if (node->lefttree != NULL)
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SetChangedParamList(node->lefttree, node->chgParam);
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if (node->righttree != NULL)
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SetChangedParamList(node->righttree, node->chgParam);
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}
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switch (nodeTag(node))
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{
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case T_SeqScan:
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ExecSeqReScan((SeqScan *) node, exprCtxt, parent);
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break;
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case T_IndexScan:
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ExecIndexReScan((IndexScan *) node, exprCtxt, parent);
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break;
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case T_Material:
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ExecMaterialReScan((Material *) node, exprCtxt, parent);
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break;
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case T_NestLoop:
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ExecReScanNestLoop((NestLoop *) node, exprCtxt, parent);
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break;
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case T_HashJoin:
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ExecReScanHashJoin((HashJoin *) node, exprCtxt, parent);
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break;
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case T_Hash:
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ExecReScanHash((Hash *) node, exprCtxt, parent);
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break;
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case T_Agg:
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ExecReScanAgg((Agg *) node, exprCtxt, parent);
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break;
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case T_Group:
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ExecReScanGroup((Group *) node, exprCtxt, parent);
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break;
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case T_Result:
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ExecReScanResult((Result *) node, exprCtxt, parent);
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break;
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case T_Unique:
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ExecReScanUnique((Unique *) node, exprCtxt, parent);
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break;
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case T_Sort:
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ExecReScanSort((Sort *) node, exprCtxt, parent);
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break;
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case T_MergeJoin:
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ExecReScanMergeJoin((MergeJoin *) node, exprCtxt, parent);
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break;
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case T_Append:
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ExecReScanAppend((Append *) node, exprCtxt, parent);
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break;
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case T_TidScan:
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ExecTidReScan((TidScan *) node, exprCtxt, parent);
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break;
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default:
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elog(ERROR, "ExecReScan: node type %u not supported", nodeTag(node));
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return;
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}
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if (node->chgParam != NULL)
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{
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freeList(node->chgParam);
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node->chgParam = NULL;
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}
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}
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/* ----------------------------------------------------------------
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* ExecReScanR
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*
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* XXX this does not do the right thing with indices yet.
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* ----------------------------------------------------------------
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*/
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HeapScanDesc
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ExecReScanR(Relation relDesc, /* LLL relDesc unused */
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HeapScanDesc scanDesc,
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ScanDirection direction,
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int nkeys, /* LLL nkeys unused */
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ScanKey skeys)
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{
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if (scanDesc != NULL)
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heap_rescan(scanDesc, /* scan desc */
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ScanDirectionIsBackward(direction), /* backward flag */
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skeys); /* scan keys */
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return scanDesc;
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}
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/* ----------------------------------------------------------------
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* ExecMarkPos
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*
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* Marks the current scan position.
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*
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* XXX Needs to be extended to include all the node types.
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* ----------------------------------------------------------------
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*/
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void
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ExecMarkPos(Plan *node)
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{
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switch (nodeTag(node))
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{
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case T_SeqScan:
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ExecSeqMarkPos((SeqScan *) node);
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break;
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case T_IndexScan:
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ExecIndexMarkPos((IndexScan *) node);
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break;
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case T_Material:
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ExecMaterialMarkPos((Material *) node);
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break;
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case T_Sort:
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ExecSortMarkPos((Sort *) node);
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break;
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case T_TidScan:
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ExecTidMarkPos((TidScan *) node);
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break;
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default:
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elog(DEBUG, "ExecMarkPos: node type %u not supported", nodeTag(node));
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break;
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}
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return;
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}
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/* ----------------------------------------------------------------
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* ExecRestrPos
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*
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* restores the scan position previously saved with ExecMarkPos()
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* ----------------------------------------------------------------
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*/
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void
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ExecRestrPos(Plan *node)
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{
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switch (nodeTag(node))
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{
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case T_SeqScan:
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ExecSeqRestrPos((SeqScan *) node);
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return;
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case T_IndexScan:
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ExecIndexRestrPos((IndexScan *) node);
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return;
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case T_Material:
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ExecMaterialRestrPos((Material *) node);
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return;
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case T_Sort:
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ExecSortRestrPos((Sort *) node);
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return;
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default:
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elog(DEBUG, "ExecRestrPos: node type %u not supported", nodeTag(node));
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return;
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}
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}
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