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postgres/src/backend/executor/execMain.c
Hiroshi Inoue fc5ec424ab Apply 7.1.3 changes to the current tree also.
2001-09-08 16:15:28 +00:00

1973 lines
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/*-------------------------------------------------------------------------
*
* execMain.c
* top level executor interface routines
*
* INTERFACE ROUTINES
* ExecutorStart()
* ExecutorRun()
* ExecutorEnd()
*
* The old ExecutorMain() has been replaced by ExecutorStart(),
* ExecutorRun() and ExecutorEnd()
*
* These three procedures are the external interfaces to the executor.
* In each case, the query descriptor and the execution state is required
* as arguments
*
* ExecutorStart() must be called at the beginning of any execution of any
* query plan and ExecutorEnd() should always be called at the end of
* execution of a plan.
*
* ExecutorRun accepts 'feature' and 'count' arguments that specify whether
* the plan is to be executed forwards, backwards, and for how many tuples.
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.146 2001/09/08 16:15:28 inoue Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/heap.h"
#include "commands/command.h"
#include "commands/trigger.h"
#include "executor/execdebug.h"
#include "executor/execdefs.h"
#include "miscadmin.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
#include "utils/acl.h"
/* decls for local routines only used within this module */
static TupleDesc InitPlan(CmdType operation,
Query *parseTree,
Plan *plan,
EState *estate);
static void initResultRelInfo(ResultRelInfo *resultRelInfo,
Index resultRelationIndex,
List *rangeTable,
CmdType operation);
static void EndPlan(Plan *plan, EState *estate);
static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
CmdType operation,
long numberTuples,
ScanDirection direction,
DestReceiver *destfunc);
static void ExecRetrieve(TupleTableSlot *slot,
DestReceiver *destfunc,
EState *estate);
static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
EState *estate);
static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
EState *estate);
static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid,
EState *estate);
static TupleTableSlot *EvalPlanQualNext(EState *estate);
static void EndEvalPlanQual(EState *estate);
static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
Plan *plan);
static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
CmdType operation);
static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
/* end of local decls */
/* ----------------------------------------------------------------
* ExecutorStart
*
* This routine must be called at the beginning of any execution of any
* query plan
*
* returns a TupleDesc which describes the attributes of the tuples to
* be returned by the query.
*
* NB: the CurrentMemoryContext when this is called must be the context
* to be used as the per-query context for the query plan. ExecutorRun()
* and ExecutorEnd() must be called in this same memory context.
* ----------------------------------------------------------------
*/
TupleDesc
ExecutorStart(QueryDesc *queryDesc, EState *estate)
{
TupleDesc result;
/* sanity checks */
Assert(queryDesc != NULL);
if (queryDesc->plantree->nParamExec > 0)
{
estate->es_param_exec_vals = (ParamExecData *)
palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
MemSet(estate->es_param_exec_vals, 0,
queryDesc->plantree->nParamExec * sizeof(ParamExecData));
}
/*
* Make our own private copy of the current queries snapshot data
*/
if (QuerySnapshot == NULL)
estate->es_snapshot = NULL;
else
{
estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
if (estate->es_snapshot->xcnt > 0)
{
estate->es_snapshot->xip = (TransactionId *)
palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
estate->es_snapshot->xcnt * sizeof(TransactionId));
}
}
/*
* Initialize the plan
*/
result = InitPlan(queryDesc->operation,
queryDesc->parsetree,
queryDesc->plantree,
estate);
return result;
}
/* ----------------------------------------------------------------
* ExecutorRun
*
* This is the main routine of the executor module. It accepts
* the query descriptor from the traffic cop and executes the
* query plan.
*
* ExecutorStart must have been called already.
*
* the different features supported are:
* EXEC_RUN: retrieve all tuples in the forward direction
* EXEC_FOR: retrieve 'count' number of tuples in the forward dir
* EXEC_BACK: retrieve 'count' number of tuples in the backward dir
* EXEC_RETONE: return one tuple but don't 'retrieve' it
* used in postquel function processing
*
* Note: count = 0 is interpreted as "no limit".
*
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, long count)
{
CmdType operation;
Plan *plan;
TupleTableSlot *result;
CommandDest dest;
DestReceiver *destfunc;
/*
* sanity checks
*/
Assert(queryDesc != NULL);
/*
* extract information from the query descriptor and the query
* feature.
*/
operation = queryDesc->operation;
plan = queryDesc->plantree;
dest = queryDesc->dest;
destfunc = DestToFunction(dest);
estate->es_processed = 0;
estate->es_lastoid = InvalidOid;
/*
* FIXME: the dest setup function ought to be handed the tuple desc
* for the tuples to be output, but I'm not quite sure how to get that
* info at this point. For now, passing NULL is OK because no
* existing dest setup function actually uses the pointer.
*/
(*destfunc->setup) (destfunc, (TupleDesc) NULL);
switch (feature)
{
case EXEC_RUN:
result = ExecutePlan(estate,
plan,
operation,
count,
ForwardScanDirection,
destfunc);
break;
case EXEC_FOR:
result = ExecutePlan(estate,
plan,
operation,
count,
ForwardScanDirection,
destfunc);
break;
/*
* retrieve next n "backward" tuples
*/
case EXEC_BACK:
result = ExecutePlan(estate,
plan,
operation,
count,
BackwardScanDirection,
destfunc);
break;
/*
* return one tuple but don't "retrieve" it. (this is used by
* the rule manager..) -cim 9/14/89
*/
case EXEC_RETONE:
result = ExecutePlan(estate,
plan,
operation,
ONE_TUPLE,
ForwardScanDirection,
destfunc);
break;
default:
elog(DEBUG, "ExecutorRun: Unknown feature %d", feature);
result = NULL;
break;
}
(*destfunc->cleanup) (destfunc);
return result;
}
/* ----------------------------------------------------------------
* ExecutorEnd
*
* This routine must be called at the end of execution of any
* query plan
* ----------------------------------------------------------------
*/
void
ExecutorEnd(QueryDesc *queryDesc, EState *estate)
{
/* sanity checks */
Assert(queryDesc != NULL);
EndPlan(queryDesc->plantree, estate);
if (estate->es_snapshot != NULL)
{
if (estate->es_snapshot->xcnt > 0)
pfree(estate->es_snapshot->xip);
pfree(estate->es_snapshot);
estate->es_snapshot = NULL;
}
if (estate->es_param_exec_vals != NULL)
{
pfree(estate->es_param_exec_vals);
estate->es_param_exec_vals = NULL;
}
}
/*
* ExecCheckQueryPerms
* Check access permissions for all relations referenced in a query.
*/
static void
ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
{
/*
* Check RTEs in the query's primary rangetable.
*/
ExecCheckRTPerms(parseTree->rtable, operation);
/*
* Search for subplans and APPEND nodes to check their rangetables.
*/
ExecCheckPlanPerms(plan, parseTree->rtable, operation);
}
/*
* ExecCheckPlanPerms
* Recursively scan the plan tree to check access permissions in
* subplans.
*/
static void
ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
{
List *subp;
if (plan == NULL)
return;
/* Check subplans, which we assume are plain SELECT queries */
foreach(subp, plan->initPlan)
{
SubPlan *subplan = (SubPlan *) lfirst(subp);
ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
}
foreach(subp, plan->subPlan)
{
SubPlan *subplan = (SubPlan *) lfirst(subp);
ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
}
/* Check lower plan nodes */
ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
/* Do node-type-specific checks */
switch (nodeTag(plan))
{
case T_SubqueryScan:
{
SubqueryScan *scan = (SubqueryScan *) plan;
RangeTblEntry *rte;
/* Recursively check the subquery */
rte = rt_fetch(scan->scan.scanrelid, rangeTable);
Assert(rte->subquery != NULL);
ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
break;
}
case T_Append:
{
Append *app = (Append *) plan;
List *appendplans;
foreach(appendplans, app->appendplans)
{
ExecCheckPlanPerms((Plan *) lfirst(appendplans),
rangeTable,
operation);
}
break;
}
default:
break;
}
}
/*
* ExecCheckRTPerms
* Check access permissions for all relations listed in a range table.
*/
static void
ExecCheckRTPerms(List *rangeTable, CmdType operation)
{
List *lp;
foreach(lp, rangeTable)
{
RangeTblEntry *rte = lfirst(lp);
ExecCheckRTEPerms(rte, operation);
}
}
/*
* ExecCheckRTEPerms
* Check access permissions for a single RTE.
*/
static void
ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
{
char *relName;
Oid userid;
int32 aclcheck_result;
/*
* If it's a subquery RTE, ignore it --- it will be checked when
* ExecCheckPlanPerms finds the SubqueryScan node for it.
*/
if (rte->subquery)
return;
relName = rte->relname;
/*
* userid to check as: current user unless we have a setuid
* indication.
*
* Note: GetUserId() is presently fast enough that there's no harm in
* calling it separately for each RTE. If that stops being true, we
* could call it once in ExecCheckQueryPerms and pass the userid down
* from there. But for now, no need for the extra clutter.
*/
userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
#define CHECK(MODE) pg_aclcheck(relName, userid, MODE)
if (rte->checkForRead)
{
aclcheck_result = CHECK(ACL_SELECT);
if (aclcheck_result != ACLCHECK_OK)
elog(ERROR, "%s: %s",
relName, aclcheck_error_strings[aclcheck_result]);
}
if (rte->checkForWrite)
{
/*
* Note: write access in a SELECT context means SELECT FOR UPDATE.
* Right now we don't distinguish that from true update as far as
* permissions checks are concerned.
*/
switch (operation)
{
case CMD_INSERT:
aclcheck_result = CHECK(ACL_INSERT);
break;
case CMD_SELECT:
case CMD_UPDATE:
aclcheck_result = CHECK(ACL_UPDATE);
break;
case CMD_DELETE:
aclcheck_result = CHECK(ACL_DELETE);
break;
default:
elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
operation);
aclcheck_result = ACLCHECK_OK; /* keep compiler quiet */
break;
}
if (aclcheck_result != ACLCHECK_OK)
elog(ERROR, "%s: %s",
relName, aclcheck_error_strings[aclcheck_result]);
}
}
/* ===============================================================
* ===============================================================
static routines follow
* ===============================================================
* ===============================================================
*/
typedef struct execRowMark
{
Relation relation;
Index rti;
char resname[32];
} execRowMark;
typedef struct evalPlanQual
{
Plan *plan;
Index rti;
EState estate;
struct evalPlanQual *free;
} evalPlanQual;
/* ----------------------------------------------------------------
* InitPlan
*
* Initializes the query plan: open files, allocate storage
* and start up the rule manager
* ----------------------------------------------------------------
*/
static TupleDesc
InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
{
List *rangeTable;
Relation intoRelationDesc;
TupleDesc tupType;
/*
* Do permissions checks.
*/
ExecCheckQueryPerms(operation, parseTree, plan);
/*
* get information from query descriptor
*/
rangeTable = parseTree->rtable;
/*
* initialize the node's execution state
*/
estate->es_range_table = rangeTable;
/*
* if there is a result relation, initialize result relation stuff
*/
if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
{
List *resultRelations = parseTree->resultRelations;
int numResultRelations;
ResultRelInfo *resultRelInfos;
if (resultRelations != NIL)
{
/*
* Multiple result relations (due to inheritance)
* parseTree->resultRelations identifies them all
*/
ResultRelInfo *resultRelInfo;
numResultRelations = length(resultRelations);
resultRelInfos = (ResultRelInfo *)
palloc(numResultRelations * sizeof(ResultRelInfo));
resultRelInfo = resultRelInfos;
while (resultRelations != NIL)
{
initResultRelInfo(resultRelInfo,
lfirsti(resultRelations),
rangeTable,
operation);
resultRelInfo++;
resultRelations = lnext(resultRelations);
}
}
else
{
/*
* Single result relation identified by
* parseTree->resultRelation
*/
numResultRelations = 1;
resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
initResultRelInfo(resultRelInfos,
parseTree->resultRelation,
rangeTable,
operation);
}
estate->es_result_relations = resultRelInfos;
estate->es_num_result_relations = numResultRelations;
/* Initialize to first or only result rel */
estate->es_result_relation_info = resultRelInfos;
}
else
{
/*
* if no result relation, then set state appropriately
*/
estate->es_result_relations = NULL;
estate->es_num_result_relations = 0;
estate->es_result_relation_info = NULL;
}
/*
* Have to lock relations selected for update
*/
estate->es_rowMark = NIL;
if (parseTree->rowMarks != NIL)
{
List *l;
foreach(l, parseTree->rowMarks)
{
Index rti = lfirsti(l);
Oid relid = getrelid(rti, rangeTable);
Relation relation;
execRowMark *erm;
relation = heap_open(relid, RowShareLock);
erm = (execRowMark *) palloc(sizeof(execRowMark));
erm->relation = relation;
erm->rti = rti;
sprintf(erm->resname, "ctid%u", rti);
estate->es_rowMark = lappend(estate->es_rowMark, erm);
}
}
/*
* initialize the executor "tuple" table. We need slots for all the
* plan nodes, plus possibly output slots for the junkfilter(s).
* At this point we aren't sure if we need junkfilters, so just add
* slots for them unconditionally.
*/
{
int nSlots = ExecCountSlotsNode(plan);
if (parseTree->resultRelations != NIL)
nSlots += length(parseTree->resultRelations);
else
nSlots += 1;
estate->es_tupleTable = ExecCreateTupleTable(nSlots);
}
/* mark EvalPlanQual not active */
estate->es_origPlan = plan;
estate->es_evalPlanQual = NULL;
estate->es_evTuple = NULL;
estate->es_evTupleNull = NULL;
estate->es_useEvalPlan = false;
/*
* initialize the private state information for all the nodes in the
* query tree. This opens files, allocates storage and leaves us
* ready to start processing tuples.
*/
ExecInitNode(plan, estate, NULL);
/*
* Get the tuple descriptor describing the type of tuples to return.
* (this is especially important if we are creating a relation with
* "retrieve into")
*/
tupType = ExecGetTupType(plan); /* tuple descriptor */
/*
* Initialize the junk filter if needed. SELECT and INSERT queries
* need a filter if there are any junk attrs in the tlist. UPDATE and
* DELETE always need one, since there's always a junk 'ctid'
* attribute present --- no need to look first.
*/
{
bool junk_filter_needed = false;
List *tlist;
switch (operation)
{
case CMD_SELECT:
case CMD_INSERT:
foreach(tlist, plan->targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tlist);
if (tle->resdom->resjunk)
{
junk_filter_needed = true;
break;
}
}
break;
case CMD_UPDATE:
case CMD_DELETE:
junk_filter_needed = true;
break;
default:
break;
}
if (junk_filter_needed)
{
/*
* If there are multiple result relations, each one needs its
* own junk filter. Note this is only possible for
* UPDATE/DELETE, so we can't be fooled by some needing a
* filter and some not.
*/
if (parseTree->resultRelations != NIL)
{
List *subplans;
ResultRelInfo *resultRelInfo;
/* Top plan had better be an Append here. */
Assert(IsA(plan, Append));
Assert(((Append *) plan)->isTarget);
subplans = ((Append *) plan)->appendplans;
Assert(length(subplans) == estate->es_num_result_relations);
resultRelInfo = estate->es_result_relations;
while (subplans != NIL)
{
Plan *subplan = (Plan *) lfirst(subplans);
JunkFilter *j;
j = ExecInitJunkFilter(subplan->targetlist,
ExecGetTupType(subplan),
ExecAllocTableSlot(estate->es_tupleTable));
resultRelInfo->ri_junkFilter = j;
resultRelInfo++;
subplans = lnext(subplans);
}
/*
* Set active junkfilter too; at this point ExecInitAppend
* has already selected an active result relation...
*/
estate->es_junkFilter =
estate->es_result_relation_info->ri_junkFilter;
}
else
{
/* Normal case with just one JunkFilter */
JunkFilter *j;
j = ExecInitJunkFilter(plan->targetlist,
tupType,
ExecAllocTableSlot(estate->es_tupleTable));
estate->es_junkFilter = j;
if (estate->es_result_relation_info)
estate->es_result_relation_info->ri_junkFilter = j;
/* For SELECT, want to return the cleaned tuple type */
if (operation == CMD_SELECT)
tupType = j->jf_cleanTupType;
}
}
else
estate->es_junkFilter = NULL;
}
/*
* initialize the "into" relation
*/
intoRelationDesc = (Relation) NULL;
if (operation == CMD_SELECT)
{
char *intoName;
Oid intoRelationId;
TupleDesc tupdesc;
if (!parseTree->isPortal)
{
/*
* a select into table
*/
if (parseTree->into != NULL)
{
/*
* create the "into" relation
*/
intoName = parseTree->into;
/*
* have to copy tupType to get rid of constraints
*/
tupdesc = CreateTupleDescCopy(tupType);
intoRelationId =
heap_create_with_catalog(intoName,
tupdesc,
RELKIND_RELATION, true,
parseTree->isTemp,
allowSystemTableMods);
FreeTupleDesc(tupdesc);
/*
* Advance command counter so that the newly-created
* relation's catalog tuples will be visible to heap_open.
*/
CommandCounterIncrement();
/*
* If necessary, create a TOAST table for the into
* relation. Note that AlterTableCreateToastTable ends
* with CommandCounterIncrement(), so that the TOAST table
* will be visible for insertion.
*/
AlterTableCreateToastTable(intoName, true);
intoRelationDesc = heap_open(intoRelationId,
AccessExclusiveLock);
}
}
}
estate->es_into_relation_descriptor = intoRelationDesc;
return tupType;
}
/*
* Initialize ResultRelInfo data for one result relation
*/
static void
initResultRelInfo(ResultRelInfo *resultRelInfo,
Index resultRelationIndex,
List *rangeTable,
CmdType operation)
{
Oid resultRelationOid;
Relation resultRelationDesc;
resultRelationOid = getrelid(resultRelationIndex, rangeTable);
resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
switch (resultRelationDesc->rd_rel->relkind)
{
case RELKIND_SEQUENCE:
elog(ERROR, "You can't change sequence relation %s",
RelationGetRelationName(resultRelationDesc));
break;
case RELKIND_TOASTVALUE:
elog(ERROR, "You can't change toast relation %s",
RelationGetRelationName(resultRelationDesc));
break;
case RELKIND_VIEW:
elog(ERROR, "You can't change view relation %s",
RelationGetRelationName(resultRelationDesc));
break;
}
MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
resultRelInfo->type = T_ResultRelInfo;
resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
resultRelInfo->ri_RelationDesc = resultRelationDesc;
resultRelInfo->ri_NumIndices = 0;
resultRelInfo->ri_IndexRelationDescs = NULL;
resultRelInfo->ri_IndexRelationInfo = NULL;
resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
resultRelInfo->ri_TrigFunctions = NULL;
resultRelInfo->ri_ConstraintExprs = NULL;
resultRelInfo->ri_junkFilter = NULL;
/*
* If there are indices on the result relation, open them and save
* descriptors in the result relation info, so that we can add new
* index entries for the tuples we add/update. We need not do this
* for a DELETE, however, since deletion doesn't affect indexes.
*/
if (resultRelationDesc->rd_rel->relhasindex &&
operation != CMD_DELETE)
ExecOpenIndices(resultRelInfo);
}
/* ----------------------------------------------------------------
* EndPlan
*
* Cleans up the query plan -- closes files and free up storages
* ----------------------------------------------------------------
*/
static void
EndPlan(Plan *plan, EState *estate)
{
ResultRelInfo *resultRelInfo;
int i;
List *l;
/*
* shut down any PlanQual processing we were doing
*/
if (estate->es_evalPlanQual != NULL)
EndEvalPlanQual(estate);
/*
* shut down the node-type-specific query processing
*/
ExecEndNode(plan, plan);
/*
* destroy the executor "tuple" table.
*/
ExecDropTupleTable(estate->es_tupleTable, true);
estate->es_tupleTable = NULL;
/*
* close the result relation(s) if any, but hold locks until xact
* commit. Also clean up junkfilters if present.
*/
resultRelInfo = estate->es_result_relations;
for (i = estate->es_num_result_relations; i > 0; i--)
{
/* Close indices and then the relation itself */
ExecCloseIndices(resultRelInfo);
heap_close(resultRelInfo->ri_RelationDesc, NoLock);
/* Delete the junkfilter if any */
if (resultRelInfo->ri_junkFilter != NULL)
ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
resultRelInfo++;
}
/*
* close the "into" relation if necessary, again keeping lock
*/
if (estate->es_into_relation_descriptor != NULL)
heap_close(estate->es_into_relation_descriptor, NoLock);
/*
* There might be a junkfilter without a result relation.
*/
if (estate->es_num_result_relations == 0 &&
estate->es_junkFilter != NULL)
{
ExecFreeJunkFilter(estate->es_junkFilter);
estate->es_junkFilter = NULL;
}
/*
* close any relations selected FOR UPDATE, again keeping locks
*/
foreach(l, estate->es_rowMark)
{
execRowMark *erm = lfirst(l);
heap_close(erm->relation, NoLock);
}
}
/* ----------------------------------------------------------------
* ExecutePlan
*
* processes the query plan to retrieve 'numberTuples' tuples in the
* direction specified.
* Retrieves all tuples if tupleCount is 0
*
* result is either a slot containing the last tuple in the case
* of a RETRIEVE or NULL otherwise.
*
* Note: the ctid attribute is a 'junk' attribute that is removed before the
* user can see it
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecutePlan(EState *estate,
Plan *plan,
CmdType operation,
long numberTuples,
ScanDirection direction,
DestReceiver *destfunc)
{
JunkFilter *junkfilter;
TupleTableSlot *slot;
ItemPointer tupleid = NULL;
ItemPointerData tuple_ctid;
long current_tuple_count;
TupleTableSlot *result;
/*
* initialize local variables
*/
slot = NULL;
current_tuple_count = 0;
result = NULL;
/*
* Set the direction.
*/
estate->es_direction = direction;
/*
* Loop until we've processed the proper number of tuples from the
* plan.
*/
for (;;)
{
/* Reset the per-output-tuple exprcontext */
ResetPerTupleExprContext(estate);
/*
* Execute the plan and obtain a tuple
*/
/* at the top level, the parent of a plan (2nd arg) is itself */
lnext: ;
if (estate->es_useEvalPlan)
{
slot = EvalPlanQualNext(estate);
if (TupIsNull(slot))
slot = ExecProcNode(plan, plan);
}
else
slot = ExecProcNode(plan, plan);
/*
* if the tuple is null, then we assume there is nothing more to
* process so we just return null...
*/
if (TupIsNull(slot))
{
result = NULL;
break;
}
/*
* if we have a junk filter, then project a new tuple with the
* junk removed.
*
* Store this new "clean" tuple in the junkfilter's resultSlot.
* (Formerly, we stored it back over the "dirty" tuple, which is
* WRONG because that tuple slot has the wrong descriptor.)
*
* Also, extract all the junk information we need.
*/
if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
{
Datum datum;
HeapTuple newTuple;
bool isNull;
/*
* extract the 'ctid' junk attribute.
*/
if (operation == CMD_UPDATE || operation == CMD_DELETE)
{
if (!ExecGetJunkAttribute(junkfilter,
slot,
"ctid",
&datum,
&isNull))
elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
tupleid = (ItemPointer) DatumGetPointer(datum);
tuple_ctid = *tupleid; /* make sure we don't free the
* ctid!! */
tupleid = &tuple_ctid;
}
else if (estate->es_rowMark != NIL)
{
List *l;
lmark: ;
foreach(l, estate->es_rowMark)
{
execRowMark *erm = lfirst(l);
Buffer buffer;
HeapTupleData tuple;
TupleTableSlot *newSlot;
int test;
if (!ExecGetJunkAttribute(junkfilter,
slot,
erm->resname,
&datum,
&isNull))
elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
erm->resname);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
erm->resname);
tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
test = heap_mark4update(erm->relation, &tuple, &buffer);
ReleaseBuffer(buffer);
switch (test)
{
case HeapTupleSelfUpdated:
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (XactIsoLevel == XACT_SERIALIZABLE)
elog(ERROR, "Can't serialize access due to concurrent update");
if (!(ItemPointerEquals(&(tuple.t_self),
(ItemPointer) DatumGetPointer(datum))))
{
newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
if (!(TupIsNull(newSlot)))
{
slot = newSlot;
estate->es_useEvalPlan = true;
goto lmark;
}
}
/*
* if tuple was deleted or PlanQual failed for
* updated tuple - we must not return this
* tuple!
*/
goto lnext;
default:
elog(ERROR, "Unknown status %u from heap_mark4update", test);
return (NULL);
}
}
}
/*
* Finally create a new "clean" tuple with all junk attributes
* removed
*/
newTuple = ExecRemoveJunk(junkfilter, slot);
slot = ExecStoreTuple(newTuple, /* tuple to store */
junkfilter->jf_resultSlot, /* dest slot */
InvalidBuffer, /* this tuple has no
* buffer */
true); /* tuple should be pfreed */
} /* if (junkfilter... */
/*
* now that we have a tuple, do the appropriate thing with it..
* either return it to the user, add it to a relation someplace,
* delete it from a relation, or modify some of its attributes.
*/
switch (operation)
{
case CMD_SELECT:
ExecRetrieve(slot, /* slot containing tuple */
destfunc, /* destination's tuple-receiver
* obj */
estate); /* */
result = slot;
break;
case CMD_INSERT:
ExecAppend(slot, tupleid, estate);
result = NULL;
break;
case CMD_DELETE:
ExecDelete(slot, tupleid, estate);
result = NULL;
break;
case CMD_UPDATE:
ExecReplace(slot, tupleid, estate);
result = NULL;
break;
default:
elog(DEBUG, "ExecutePlan: unknown operation in queryDesc");
result = NULL;
break;
}
/*
* check our tuple count.. if we've processed the proper number
* then quit, else loop again and process more tuples..
*/
current_tuple_count++;
if (numberTuples == current_tuple_count)
break;
}
/*
* here, result is either a slot containing a tuple in the case of a
* RETRIEVE or NULL otherwise.
*/
return result;
}
/* ----------------------------------------------------------------
* ExecRetrieve
*
* RETRIEVEs are easy.. we just pass the tuple to the appropriate
* print function. The only complexity is when we do a
* "retrieve into", in which case we insert the tuple into
* the appropriate relation (note: this is a newly created relation
* so we don't need to worry about indices or locks.)
* ----------------------------------------------------------------
*/
static void
ExecRetrieve(TupleTableSlot *slot,
DestReceiver *destfunc,
EState *estate)
{
HeapTuple tuple;
TupleDesc attrtype;
/*
* get the heap tuple out of the tuple table slot
*/
tuple = slot->val;
attrtype = slot->ttc_tupleDescriptor;
/*
* insert the tuple into the "into relation"
*/
if (estate->es_into_relation_descriptor != NULL)
{
heap_insert(estate->es_into_relation_descriptor, tuple);
IncrAppended();
}
/*
* send the tuple to the front end (or the screen)
*/
(*destfunc->receiveTuple) (tuple, attrtype, destfunc);
IncrRetrieved();
(estate->es_processed)++;
}
/* ----------------------------------------------------------------
* ExecAppend
*
* APPENDs are trickier.. we have to insert the tuple into
* the base relation and insert appropriate tuples into the
* index relations.
* ----------------------------------------------------------------
*/
static void
ExecAppend(TupleTableSlot *slot,
ItemPointer tupleid,
EState *estate)
{
HeapTuple tuple;
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
int numIndices;
Oid newId;
/*
* get the heap tuple out of the tuple table slot
*/
tuple = slot->val;
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/* BEFORE ROW INSERT Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
{
HeapTuple newtuple;
newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
if (newtuple == NULL) /* "do nothing" */
return;
if (newtuple != tuple) /* modified by Trigger(s) */
{
/*
* Insert modified tuple into tuple table slot, replacing the
* original. We assume that it was allocated in per-tuple
* memory context, and therefore will go away by itself. The
* tuple table slot should not try to clear it.
*/
ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
tuple = newtuple;
}
}
/*
* Check the constraints of the tuple
*/
if (resultRelationDesc->rd_att->constr)
ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
/*
* insert the tuple
*/
newId = heap_insert(resultRelationDesc, tuple);
setLastTid(&(tuple->t_self));
IncrAppended();
(estate->es_processed)++;
estate->es_lastoid = newId;
/*
* process indices
*
* Note: heap_insert adds a new tuple to a relation. As a side effect,
* the tupleid of the new tuple is placed in the new tuple's t_ctid
* field.
*/
numIndices = resultRelInfo->ri_NumIndices;
if (numIndices > 0)
ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
/* AFTER ROW INSERT Triggers */
if (resultRelInfo->ri_TrigDesc)
ExecARInsertTriggers(estate, resultRelInfo, tuple);
}
/* ----------------------------------------------------------------
* ExecDelete
*
* DELETE is like append, we delete the tuple and its
* index tuples.
* ----------------------------------------------------------------
*/
static void
ExecDelete(TupleTableSlot *slot,
ItemPointer tupleid,
EState *estate)
{
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
ItemPointerData ctid;
int result;
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/* BEFORE ROW DELETE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
{
bool dodelete;
dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
if (!dodelete) /* "do nothing" */
return;
}
/*
* delete the tuple
*/
ldelete:;
result = heap_delete(resultRelationDesc, tupleid, &ctid);
switch (result)
{
case HeapTupleSelfUpdated:
return;
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (XactIsoLevel == XACT_SERIALIZABLE)
elog(ERROR, "Can't serialize access due to concurrent update");
else if (!(ItemPointerEquals(tupleid, &ctid)))
{
TupleTableSlot *epqslot = EvalPlanQual(estate,
resultRelInfo->ri_RangeTableIndex, &ctid);
if (!TupIsNull(epqslot))
{
*tupleid = ctid;
goto ldelete;
}
}
/* tuple already deleted; nothing to do */
return;
default:
elog(ERROR, "Unknown status %u from heap_delete", result);
return;
}
IncrDeleted();
(estate->es_processed)++;
/*
* Note: Normally one would think that we have to delete index tuples
* associated with the heap tuple now..
*
* ... but in POSTGRES, we have no need to do this because the vacuum
* daemon automatically opens an index scan and deletes index tuples
* when it finds deleted heap tuples. -cim 9/27/89
*/
/* AFTER ROW DELETE Triggers */
if (resultRelInfo->ri_TrigDesc)
ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
}
/* ----------------------------------------------------------------
* ExecReplace
*
* note: we can't run replace queries with transactions
* off because replaces are actually appends and our
* scan will mistakenly loop forever, replacing the tuple
* it just appended.. This should be fixed but until it
* is, we don't want to get stuck in an infinite loop
* which corrupts your database..
* ----------------------------------------------------------------
*/
static void
ExecReplace(TupleTableSlot *slot,
ItemPointer tupleid,
EState *estate)
{
HeapTuple tuple;
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
ItemPointerData ctid;
int result;
int numIndices;
/*
* abort the operation if not running transactions
*/
if (IsBootstrapProcessingMode())
{
elog(NOTICE, "ExecReplace: replace can't run without transactions");
return;
}
/*
* get the heap tuple out of the tuple table slot
*/
tuple = slot->val;
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/* BEFORE ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
{
HeapTuple newtuple;
newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
tupleid, tuple);
if (newtuple == NULL) /* "do nothing" */
return;
if (newtuple != tuple) /* modified by Trigger(s) */
{
/*
* Insert modified tuple into tuple table slot, replacing the
* original. We assume that it was allocated in per-tuple
* memory context, and therefore will go away by itself. The
* tuple table slot should not try to clear it.
*/
ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
tuple = newtuple;
}
}
/*
* Check the constraints of the tuple
*
* If we generate a new candidate tuple after EvalPlanQual testing,
* we must loop back here and recheck constraints. (We don't need to
* redo triggers, however. If there are any BEFORE triggers then
* trigger.c will have done mark4update to lock the correct tuple,
* so there's no need to do them again.)
*/
lreplace:;
if (resultRelationDesc->rd_att->constr)
ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
/*
* replace the heap tuple
*/
result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
switch (result)
{
case HeapTupleSelfUpdated:
return;
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (XactIsoLevel == XACT_SERIALIZABLE)
elog(ERROR, "Can't serialize access due to concurrent update");
else if (!(ItemPointerEquals(tupleid, &ctid)))
{
TupleTableSlot *epqslot = EvalPlanQual(estate,
resultRelInfo->ri_RangeTableIndex, &ctid);
if (!TupIsNull(epqslot))
{
*tupleid = ctid;
tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
slot = ExecStoreTuple(tuple,
estate->es_junkFilter->jf_resultSlot,
InvalidBuffer, true);
goto lreplace;
}
}
/* tuple already deleted; nothing to do */
return;
default:
elog(ERROR, "Unknown status %u from heap_update", result);
return;
}
IncrReplaced();
(estate->es_processed)++;
/*
* Note: instead of having to update the old index tuples associated
* with the heap tuple, all we do is form and insert new index tuples.
* This is because replaces are actually deletes and inserts and index
* tuple deletion is done automagically by the vacuum daemon. All we
* do is insert new index tuples. -cim 9/27/89
*/
/*
* process indices
*
* heap_update updates a tuple in the base relation by invalidating it
* and then appending a new tuple to the relation. As a side effect,
* the tupleid of the new tuple is placed in the new tuple's t_ctid
* field. So we now insert index tuples using the new tupleid stored
* there.
*/
numIndices = resultRelInfo->ri_NumIndices;
if (numIndices > 0)
ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
/* AFTER ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc)
ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
}
static char *
ExecRelCheck(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate)
{
Relation rel = resultRelInfo->ri_RelationDesc;
int ncheck = rel->rd_att->constr->num_check;
ConstrCheck *check = rel->rd_att->constr->check;
ExprContext *econtext;
MemoryContext oldContext;
List *qual;
int i;
/*
* If first time through for this result relation, build expression
* nodetrees for rel's constraint expressions. Keep them in the
* per-query memory context so they'll survive throughout the query.
*/
if (resultRelInfo->ri_ConstraintExprs == NULL)
{
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
resultRelInfo->ri_ConstraintExprs =
(List **) palloc(ncheck * sizeof(List *));
for (i = 0; i < ncheck; i++)
{
qual = (List *) stringToNode(check[i].ccbin);
resultRelInfo->ri_ConstraintExprs[i] = qual;
}
MemoryContextSwitchTo(oldContext);
}
/*
* We will use the EState's per-tuple context for evaluating
* constraint expressions (creating it if it's not already there).
*/
econtext = GetPerTupleExprContext(estate);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
/* And evaluate the constraints */
for (i = 0; i < ncheck; i++)
{
qual = resultRelInfo->ri_ConstraintExprs[i];
/*
* NOTE: SQL92 specifies that a NULL result from a constraint
* expression is not to be treated as a failure. Therefore, tell
* ExecQual to return TRUE for NULL.
*/
if (!ExecQual(qual, econtext, true))
return check[i].ccname;
}
/* NULL result means no error */
return (char *) NULL;
}
void
ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate)
{
Relation rel = resultRelInfo->ri_RelationDesc;
HeapTuple tuple = slot->val;
TupleConstr *constr = rel->rd_att->constr;
Assert(constr);
if (constr->has_not_null)
{
int natts = rel->rd_att->natts;
int attrChk;
for (attrChk = 1; attrChk <= natts; attrChk++)
{
if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
heap_attisnull(tuple, attrChk))
elog(ERROR, "%s: Fail to add null value in not null attribute %s",
caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
}
}
if (constr->num_check > 0)
{
char *failed;
if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
elog(ERROR, "%s: rejected due to CHECK constraint %s",
caller, failed);
}
}
/*
* Check a modified tuple to see if we want to process its updated version
* under READ COMMITTED rules.
*
* See backend/executor/README for some info about how this works.
*/
TupleTableSlot *
EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
{
evalPlanQual *epq;
EState *epqstate;
Relation relation;
HeapTupleData tuple;
HeapTuple copyTuple = NULL;
int rtsize;
bool endNode;
Assert(rti != 0);
/*
* find relation containing target tuple
*/
if (estate->es_result_relation_info != NULL &&
estate->es_result_relation_info->ri_RangeTableIndex == rti)
{
relation = estate->es_result_relation_info->ri_RelationDesc;
}
else
{
List *l;
relation = NULL;
foreach(l, estate->es_rowMark)
{
if (((execRowMark *) lfirst(l))->rti == rti)
{
relation = ((execRowMark *) lfirst(l))->relation;
break;
}
}
if (relation == NULL)
elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
}
/*
* fetch tid tuple
*
* Loop here to deal with updated or busy tuples
*/
tuple.t_self = *tid;
for (;;)
{
Buffer buffer;
heap_fetch(relation, SnapshotDirty, &tuple, &buffer, NULL);
if (tuple.t_data != NULL)
{
TransactionId xwait = SnapshotDirty->xmax;
if (TransactionIdIsValid(SnapshotDirty->xmin))
elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
/*
* If tuple is being updated by other transaction then we have
* to wait for its commit/abort.
*/
if (TransactionIdIsValid(xwait))
{
ReleaseBuffer(buffer);
XactLockTableWait(xwait);
continue;
}
/*
* We got tuple - now copy it for use by recheck query.
*/
copyTuple = heap_copytuple(&tuple);
ReleaseBuffer(buffer);
break;
}
/*
* Oops! Invalid tuple. Have to check is it updated or deleted.
* Note that it's possible to get invalid SnapshotDirty->tid if
* tuple updated by this transaction. Have we to check this ?
*/
if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
!(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
{
/* updated, so look at the updated copy */
tuple.t_self = SnapshotDirty->tid;
continue;
}
/*
* Deleted or updated by this transaction; forget it.
*/
return NULL;
}
/*
* For UPDATE/DELETE we have to return tid of actual row we're
* executing PQ for.
*/
*tid = tuple.t_self;
/*
* Need to run a recheck subquery. Find or create a PQ stack entry.
*/
epq = (evalPlanQual *) estate->es_evalPlanQual;
rtsize = length(estate->es_range_table);
endNode = true;
if (epq != NULL && epq->rti == 0)
{
/* Top PQ stack entry is idle, so re-use it */
Assert(!(estate->es_useEvalPlan) &&
epq->estate.es_evalPlanQual == NULL);
epq->rti = rti;
endNode = false;
}
/*
* If this is request for another RTE - Ra, - then we have to check
* wasn't PlanQual requested for Ra already and if so then Ra' row was
* updated again and we have to re-start old execution for Ra and
* forget all what we done after Ra was suspended. Cool? -:))
*/
if (epq != NULL && epq->rti != rti &&
epq->estate.es_evTuple[rti - 1] != NULL)
{
do
{
evalPlanQual *oldepq;
/* pop previous PlanQual from the stack */
epqstate = &(epq->estate);
oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
Assert(oldepq->rti != 0);
/* stop execution */
ExecEndNode(epq->plan, epq->plan);
ExecDropTupleTable(epqstate->es_tupleTable, true);
epqstate->es_tupleTable = NULL;
heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
epqstate->es_evTuple[epq->rti - 1] = NULL;
/* push current PQ to freePQ stack */
oldepq->free = epq;
epq = oldepq;
estate->es_evalPlanQual = (Pointer) epq;
} while (epq->rti != rti);
}
/*
* If we are requested for another RTE then we have to suspend
* execution of current PlanQual and start execution for new one.
*/
if (epq == NULL || epq->rti != rti)
{
/* try to reuse plan used previously */
evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
if (newepq == NULL) /* first call or freePQ stack is empty */
{
newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
newepq->free = NULL;
/*
* Each stack level has its own copy of the plan tree. This
* is wasteful, but necessary as long as plan nodes point to
* exec state nodes rather than vice versa. Note that copyfuncs.c
* doesn't attempt to copy the exec state nodes, which is a good
* thing in this situation.
*/
newepq->plan = copyObject(estate->es_origPlan);
/*
* Init stack level's EState. We share top level's copy of
* es_result_relations array and other non-changing status.
* We need our own tupletable, es_param_exec_vals, and other
* changeable state.
*/
epqstate = &(newepq->estate);
memcpy(epqstate, estate, sizeof(EState));
epqstate->es_direction = ForwardScanDirection;
if (estate->es_origPlan->nParamExec > 0)
epqstate->es_param_exec_vals = (ParamExecData *)
palloc(estate->es_origPlan->nParamExec *
sizeof(ParamExecData));
epqstate->es_tupleTable = NULL;
epqstate->es_per_tuple_exprcontext = NULL;
/*
* Each epqstate must have its own es_evTupleNull state,
* but all the stack entries share es_evTuple state. This
* allows sub-rechecks to inherit the value being examined by
* an outer recheck.
*/
epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
if (epq == NULL)
{
/* first PQ stack entry */
epqstate->es_evTuple = (HeapTuple *)
palloc(rtsize * sizeof(HeapTuple));
memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
}
else
{
/* later stack entries share the same storage */
epqstate->es_evTuple = epq->estate.es_evTuple;
}
}
else
{
/* recycle previously used EState */
epqstate = &(newepq->estate);
}
/* push current PQ to the stack */
epqstate->es_evalPlanQual = (Pointer) epq;
epq = newepq;
estate->es_evalPlanQual = (Pointer) epq;
epq->rti = rti;
endNode = false;
}
Assert(epq->rti == rti);
epqstate = &(epq->estate);
/*
* Ok - we're requested for the same RTE. Unfortunately we still
* have to end and restart execution of the plan, because ExecReScan
* wouldn't ensure that upper plan nodes would reset themselves. We
* could make that work if insertion of the target tuple were integrated
* with the Param mechanism somehow, so that the upper plan nodes know
* that their children's outputs have changed.
*/
if (endNode)
{
/* stop execution */
ExecEndNode(epq->plan, epq->plan);
ExecDropTupleTable(epqstate->es_tupleTable, true);
epqstate->es_tupleTable = NULL;
}
/*
* free old RTE' tuple, if any, and store target tuple where relation's
* scan node will see it
*/
if (epqstate->es_evTuple[rti - 1] != NULL)
heap_freetuple(epqstate->es_evTuple[rti - 1]);
epqstate->es_evTuple[rti - 1] = copyTuple;
/*
* Initialize for new recheck query; be careful to copy down state
* that might have changed in top EState.
*/
epqstate->es_result_relation_info = estate->es_result_relation_info;
epqstate->es_junkFilter = estate->es_junkFilter;
if (estate->es_origPlan->nParamExec > 0)
memset(epqstate->es_param_exec_vals, 0,
estate->es_origPlan->nParamExec * sizeof(ParamExecData));
memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
epqstate->es_useEvalPlan = false;
Assert(epqstate->es_tupleTable == NULL);
epqstate->es_tupleTable =
ExecCreateTupleTable(estate->es_tupleTable->size);
ExecInitNode(epq->plan, epqstate, NULL);
return EvalPlanQualNext(estate);
}
static TupleTableSlot *
EvalPlanQualNext(EState *estate)
{
evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
EState *epqstate = &(epq->estate);
evalPlanQual *oldepq;
TupleTableSlot *slot;
Assert(epq->rti != 0);
lpqnext:;
slot = ExecProcNode(epq->plan, epq->plan);
/*
* No more tuples for this PQ. Continue previous one.
*/
if (TupIsNull(slot))
{
/* stop execution */
ExecEndNode(epq->plan, epq->plan);
ExecDropTupleTable(epqstate->es_tupleTable, true);
epqstate->es_tupleTable = NULL;
heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
epqstate->es_evTuple[epq->rti - 1] = NULL;
/* pop old PQ from the stack */
oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
if (oldepq == (evalPlanQual *) NULL)
{
epq->rti = 0; /* this is the first (oldest) */
estate->es_useEvalPlan = false; /* PQ - mark as free and */
return (NULL); /* continue Query execution */
}
Assert(oldepq->rti != 0);
/* push current PQ to freePQ stack */
oldepq->free = epq;
epq = oldepq;
epqstate = &(epq->estate);
estate->es_evalPlanQual = (Pointer) epq;
goto lpqnext;
}
return (slot);
}
static void
EndEvalPlanQual(EState *estate)
{
evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
EState *epqstate = &(epq->estate);
evalPlanQual *oldepq;
if (epq->rti == 0) /* plans already shutdowned */
{
Assert(epq->estate.es_evalPlanQual == NULL);
return;
}
for (;;)
{
/* stop execution */
ExecEndNode(epq->plan, epq->plan);
ExecDropTupleTable(epqstate->es_tupleTable, true);
epqstate->es_tupleTable = NULL;
if (epqstate->es_evTuple[epq->rti - 1] != NULL)
{
heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
epqstate->es_evTuple[epq->rti - 1] = NULL;
}
/* pop old PQ from the stack */
oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
if (oldepq == (evalPlanQual *) NULL)
{
epq->rti = 0; /* this is the first (oldest) */
estate->es_useEvalPlan = false; /* PQ - mark as free */
break;
}
Assert(oldepq->rti != 0);
/* push current PQ to freePQ stack */
oldepq->free = epq;
epq = oldepq;
epqstate = &(epq->estate);
estate->es_evalPlanQual = (Pointer) epq;
}
}
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