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postgresql/src/backend/executor/execMain.c

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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* The old ExecutorMain() has been replaced by ExecutorStart(),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.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.76 1999/02/08 14:14:09 wieck Exp $
*
*-------------------------------------------------------------------------
*/
#include <string.h>
#include "postgres.h"
#include "miscadmin.h"
#include "executor/executor.h"
#include "executor/execdefs.h"
#include "executor/execdebug.h"
#include "executor/nodeIndexscan.h"
#include "utils/builtins.h"
#include "utils/palloc.h"
#include "utils/acl.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
#include "parser/parsetree.h" /* rt_fetch() */
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "commands/async.h"
/* #include "access/localam.h" */
#include "optimizer/var.h"
#include "access/heapam.h"
#include "access/xact.h"
#include "catalog/heap.h"
#include "commands/trigger.h"
void ExecCheckPerms(CmdType operation, int resultRelation, List *rangeTable,
Query *parseTree);
/* decls for local routines only used within this module */
static TupleDesc InitPlan(CmdType operation,
Query *parseTree,
Plan *plan,
EState *estate);
static void EndPlan(Plan *plan,
EState *estate);
static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
CmdType operation,
int offsetTuples,
int 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);
TupleTableSlot *EvalPlanQual(EState *estate, Index rti, ItemPointer tid);
static TupleTableSlot *EvalPlanQualNext(EState *estate);
/* end of local decls */
#ifdef QUERY_LIMIT
static int queryLimit = ALL_TUPLES;
#undef ALL_TUPLES
#define ALL_TUPLES queryLimit
int
ExecutorLimit(int limit)
{
return queryLimit = limit;
}
int
ExecutorGetLimit()
{
return queryLimit;
}
#endif
/* ----------------------------------------------------------------
* ExecutorStart
*
* This routine must be called at the beginning of any execution of any
* query plan
*
* returns (AttrInfo*) which describes the attributes of the tuples to
* be returned by the query.
*
* ----------------------------------------------------------------
*/
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);
/*
* reset buffer refcount. the current refcounts are saved and will be
* restored when ExecutorEnd is called
*
* this makes sure that when ExecutorRun's are called recursively as for
* postquel functions, the buffers pinned by one ExecutorRun will not
* be unpinned by another ExecutorRun.
*/
BufferRefCountReset(estate->es_refcount);
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
*
*
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature,
Node *limoffset, Node *limcount)
{
CmdType operation;
Plan *plan;
TupleTableSlot *result;
CommandDest dest;
DestReceiver *destfunc;
int offset = 0;
int count = 0;
/******************
* 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);
/******************
* if given get the offset of the LIMIT clause
******************
*/
if (limoffset != NULL)
{
Const *coffset;
Param *poffset;
ParamListInfo paramLI;
int i;
switch (nodeTag(limoffset))
{
case T_Const:
coffset = (Const *)limoffset;
offset = (int)(coffset->constvalue);
break;
case T_Param:
poffset = (Param *)limoffset;
paramLI = estate->es_param_list_info;
if (paramLI == NULL)
elog(ERROR, "parameter for limit offset not in executor state");
for (i = 0; paramLI[i].kind != PARAM_INVALID; i++)
{
if (paramLI[i].kind == PARAM_NUM && paramLI[i].id == poffset->paramid)
break;
}
if (paramLI[i].kind == PARAM_INVALID)
elog(ERROR, "parameter for limit offset not in executor state");
if (paramLI[i].isnull)
elog(ERROR, "limit offset cannot be NULL value");
offset = (int)(paramLI[i].value);
break;
default:
elog(ERROR, "unexpected node type %d as limit offset", nodeTag(limoffset));
}
if (offset < 0)
elog(ERROR, "limit offset cannot be negative");
}
/******************
* if given get the count of the LIMIT clause
******************
*/
if (limcount != NULL)
{
Const *ccount;
Param *pcount;
ParamListInfo paramLI;
int i;
switch (nodeTag(limcount))
{
case T_Const:
ccount = (Const *)limcount;
count = (int)(ccount->constvalue);
break;
case T_Param:
pcount = (Param *)limcount;
paramLI = estate->es_param_list_info;
if (paramLI == NULL)
elog(ERROR, "parameter for limit count not in executor state");
for (i = 0; paramLI[i].kind != PARAM_INVALID; i++)
{
if (paramLI[i].kind == PARAM_NUM && paramLI[i].id == pcount->paramid)
break;
}
if (paramLI[i].kind == PARAM_INVALID)
elog(ERROR, "parameter for limit count not in executor state");
if (paramLI[i].isnull)
elog(ERROR, "limit count cannot be NULL value");
count = (int)(paramLI[i].value);
break;
default:
elog(ERROR, "unexpected node type %d as limit count", nodeTag(limcount));
}
if (count < 0)
elog(ERROR, "limit count cannot be negative");
}
switch (feature)
{
case EXEC_RUN:
result = ExecutePlan(estate,
plan,
operation,
offset,
count,
ForwardScanDirection,
destfunc);
break;
case EXEC_FOR:
result = ExecutePlan(estate,
plan,
operation,
offset,
count,
ForwardScanDirection,
destfunc);
break;
/******************
* retrieve next n "backward" tuples
******************
*/
case EXEC_BACK:
result = ExecutePlan(estate,
plan,
operation,
offset,
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,
0,
ONE_TUPLE,
ForwardScanDirection,
destfunc);
break;
default:
result = NULL;
elog(DEBUG, "ExecutorRun: Unknown feature %d", feature);
break;
}
(*destfunc->cleanup) (destfunc);
return result;
}
/* ----------------------------------------------------------------
* ExecutorEnd
*
* This routine must be called at the end of any execution of any
* query plan
*
* returns (AttrInfo*) which describes the attributes of the tuples to
* be returned by the query.
*
* ----------------------------------------------------------------
*/
void
ExecutorEnd(QueryDesc *queryDesc, EState *estate)
{
/* sanity checks */
Assert(queryDesc != NULL);
EndPlan(queryDesc->plantree, estate);
/* restore saved refcounts. */
BufferRefCountRestore(estate->es_refcount);
}
void
ExecCheckPerms(CmdType operation,
int resultRelation,
List *rangeTable,
Query *parseTree)
{
int i = 1;
Oid relid;
HeapTuple htup;
List *lp;
List *qvars,
*tvars;
int32 ok = 1,
aclcheck_result = -1;
char *opstr;
NameData rname;
char *userName;
#define CHECK(MODE) pg_aclcheck(rname.data, userName, MODE)
userName = GetPgUserName();
foreach(lp, rangeTable)
{
RangeTblEntry *rte = lfirst(lp);
if (rte->skipAcl)
{
/*
* This happens if the access to this table is due to a view
* query rewriting - the rewrite handler checked the
* permissions against the view owner, so we just skip this
* entry.
*/
continue;
}
relid = rte->relid;
htup = SearchSysCacheTuple(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(htup))
elog(ERROR, "ExecCheckPerms: bogus RT relid: %d",
relid);
StrNCpy(rname.data,
((Form_pg_class) GETSTRUCT(htup))->relname.data,
NAMEDATALEN);
if (i == resultRelation)
{ /* this is the result relation */
qvars = pull_varnos(parseTree->qual);
tvars = pull_varnos((Node *) parseTree->targetList);
if (intMember(resultRelation, qvars) ||
intMember(resultRelation, tvars))
{
/* result relation is scanned */
ok = ((aclcheck_result = CHECK(ACL_RD)) == ACLCHECK_OK);
opstr = "read";
if (!ok)
break;
}
switch (operation)
{
case CMD_INSERT:
ok = ((aclcheck_result = CHECK(ACL_AP)) == ACLCHECK_OK) ||
((aclcheck_result = CHECK(ACL_WR)) == ACLCHECK_OK);
opstr = "append";
break;
case CMD_DELETE:
case CMD_UPDATE:
ok = ((aclcheck_result = CHECK(ACL_WR)) == ACLCHECK_OK);
opstr = "write";
break;
default:
elog(ERROR, "ExecCheckPerms: bogus operation %d",
operation);
}
}
else
{
ok = ((aclcheck_result = CHECK(ACL_RD)) == ACLCHECK_OK);
opstr = "read";
}
if (!ok)
break;
++i;
}
if (!ok)
elog(ERROR, "%s: %s", rname.data, aclcheck_error_strings[aclcheck_result]);
if (parseTree != NULL && parseTree->rowMark != NULL)
{
foreach(lp, parseTree->rowMark)
{
RowMark *rm = lfirst(lp);
if (!(rm->info & ROW_ACL_FOR_UPDATE))
continue;
relid = ((RangeTblEntry *)nth(rm->rti - 1, rangeTable))->relid;
htup = SearchSysCacheTuple(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(htup))
elog(ERROR, "ExecCheckPerms: bogus RT relid: %d",
relid);
StrNCpy(rname.data,
((Form_pg_class) GETSTRUCT(htup))->relname.data,
NAMEDATALEN);
ok = ((aclcheck_result = CHECK(ACL_WR)) == ACLCHECK_OK);
opstr = "write";
if (!ok)
elog(ERROR, "%s: %s", rname.data, 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;
int resultRelation;
Relation intoRelationDesc;
TupleDesc tupType;
List *targetList;
int len;
/******************
* get information from query descriptor
******************
*/
rangeTable = parseTree->rtable;
resultRelation = parseTree->resultRelation;
#ifndef NO_SECURITY
ExecCheckPerms(operation, resultRelation, rangeTable, parseTree);
#endif
/******************
* initialize the node's execution state
******************
*/
estate->es_range_table = rangeTable;
/******************
* initialize the BaseId counter so node base_id's
* are assigned correctly. Someday baseid's will have to
* be stored someplace other than estate because they
* should be unique per query planned.
******************
*/
estate->es_BaseId = 1;
/******************
* initialize result relation stuff
******************
*/
if (resultRelation != 0 && operation != CMD_SELECT)
{
/******************
* if we have a result relation, open it and
* initialize the result relation info stuff.
******************
*/
RelationInfo *resultRelationInfo;
Index resultRelationIndex;
RangeTblEntry *rtentry;
Oid resultRelationOid;
Relation resultRelationDesc;
resultRelationIndex = resultRelation;
rtentry = rt_fetch(resultRelationIndex, rangeTable);
resultRelationOid = rtentry->relid;
resultRelationDesc = heap_open(resultRelationOid);
if (resultRelationDesc->rd_rel->relkind == RELKIND_SEQUENCE)
elog(ERROR, "You can't change sequence relation %s",
resultRelationDesc->rd_rel->relname.data);
LockRelation(resultRelationDesc, RowExclusiveLock);
resultRelationInfo = makeNode(RelationInfo);
resultRelationInfo->ri_RangeTableIndex = resultRelationIndex;
resultRelationInfo->ri_RelationDesc = resultRelationDesc;
resultRelationInfo->ri_NumIndices = 0;
resultRelationInfo->ri_IndexRelationDescs = NULL;
resultRelationInfo->ri_IndexRelationInfo = NULL;
/******************
* open indices on result relation and save descriptors
* in the result relation information..
******************
*/
if (operation != CMD_DELETE)
ExecOpenIndices(resultRelationOid, resultRelationInfo);
estate->es_result_relation_info = resultRelationInfo;
}
else
{
/******************
* if no result relation, then set state appropriately
******************
*/
estate->es_result_relation_info = NULL;
}
/*
* Have to lock relations selected for update
*/
estate->es_rowMark = NULL;
if (parseTree->rowMark != NULL)
{
Relation relation;
Oid relid;
RowMark *rm;
List *l;
execRowMark *erm;
foreach(l, parseTree->rowMark)
{
rm = lfirst(l);
relid = ((RangeTblEntry *)nth(rm->rti - 1, rangeTable))->relid;
relation = heap_open(relid);
LockRelation(relation, RowShareLock);
if (!(rm->info & ROW_MARK_FOR_UPDATE))
continue;
erm = (execRowMark*) palloc(sizeof(execRowMark));
erm->relation = relation;
erm->rti = rm->rti;
sprintf(erm->resname, "ctid%u", rm->rti);
estate->es_rowMark = lappend(estate->es_rowMark, erm);
}
}
/******************
* initialize the executor "tuple" table.
******************
*/
{
int nSlots = ExecCountSlotsNode(plan);
TupleTable tupleTable = ExecCreateTupleTable(nSlots + 10); /* why add ten? - jolly */
estate->es_tupleTable = tupleTable;
}
/******************
* 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 */
targetList = plan->targetlist;
len = ExecTargetListLength(targetList); /* number of attributes */
/******************
* now that we have the target list, initialize the junk filter
* if this is a REPLACE or a DELETE query.
* We also init the junk filter if this is an append query
* (there might be some rule lock info there...)
* NOTE: in the future we might want to initialize the junk
* filter for all queries.
******************
* SELECT added by daveh@insightdist.com 5/20/98 to allow
* ORDER/GROUP BY have an identifier missing from the target.
*/
{
bool junk_filter_needed = false;
List *tlist;
if (operation == CMD_SELECT)
{
foreach(tlist, targetList)
{
TargetEntry *tle = lfirst(tlist);
if (tle->resdom->resjunk)
{
junk_filter_needed = true;
break;
}
}
}
if (operation == CMD_UPDATE || operation == CMD_DELETE ||
operation == CMD_INSERT ||
(operation == CMD_SELECT && junk_filter_needed))
{
JunkFilter *j = (JunkFilter *) ExecInitJunkFilter(targetList);
estate->es_junkFilter = j;
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,parseTree->isTemp);
FreeTupleDesc(tupdesc);
/******************
* XXX rather than having to call setheapoverride(true)
* and then back to false, we should change the
* arguments to heap_open() instead..
******************
*/
setheapoverride(true);
intoRelationDesc = heap_open(intoRelationId);
setheapoverride(false);
}
}
}
estate->es_into_relation_descriptor = intoRelationDesc;
estate->es_origPlan = plan;
estate->es_evalPlanQual = NULL;
estate->es_evTuple = NULL;
estate->es_useEvalPlan = false;
return tupType;
}
/* ----------------------------------------------------------------
* EndPlan
*
* Cleans up the query plan -- closes files and free up storages
* ----------------------------------------------------------------
*/
static void
EndPlan(Plan *plan, EState *estate)
{
RelationInfo *resultRelationInfo;
Relation intoRelationDesc;
/******************
* get information from state
******************
*/
resultRelationInfo = estate->es_result_relation_info;
intoRelationDesc = estate->es_into_relation_descriptor;
/******************
* shut down the query
******************
*/
ExecEndNode(plan, plan);
/******************
* destroy the executor "tuple" table.
******************
*/
{
TupleTable tupleTable = (TupleTable) estate->es_tupleTable;
ExecDestroyTupleTable(tupleTable, true); /* was missing last arg */
estate->es_tupleTable = NULL;
}
/******************
* close the result relations if necessary
******************
*/
if (resultRelationInfo != NULL)
{
Relation resultRelationDesc;
resultRelationDesc = resultRelationInfo->ri_RelationDesc;
heap_close(resultRelationDesc);
/******************
* close indices on the result relation
******************
*/
ExecCloseIndices(resultRelationInfo);
}
/******************
* close the "into" relation if necessary
******************
*/
if (intoRelationDesc != NULL)
heap_close(intoRelationDesc);
}
/* ----------------------------------------------------------------
* ExecutePlan
*
* processes the query plan to retrieve 'tupleCount' tuples in the
* direction specified.
* Retrieves all tuples if tupleCount is 0
*
* result is either a slot containing a tuple in the case
* of a RETRIEVE or NULL otherwise.
*
* ----------------------------------------------------------------
*/
/* 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,
int offsetTuples,
int numberTuples,
ScanDirection direction,
DestReceiver* destfunc)
{
JunkFilter *junkfilter;
TupleTableSlot *slot;
ItemPointer tupleid = NULL;
ItemPointerData tuple_ctid;
int 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 (;;)
{
/******************
* 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;
}
/******************
* For now we completely execute the plan and skip
* result tuples if requested by LIMIT offset.
* Finally we should try to do it in deeper levels
* if possible (during index scan)
* - Jan
******************
*/
if (offsetTuples > 0)
{
--offsetTuples;
continue;
}
/******************
* if we have a junk filter, then project a new
* tuple with the junk removed.
*
* Store this new "clean" tuple in the place of the
* original tuple.
*
* 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!");
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 != NULL)
{
List *l;
execRowMark *erm;
Buffer buffer;
HeapTupleData tuple;
TupleTableSlot *newSlot;
int test;
lmark:;
foreach (l, estate->es_rowMark)
{
erm = lfirst(l);
if (!ExecGetJunkAttribute(junkfilter,
slot,
erm->resname,
&datum,
&isNull))
elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!", erm->resname);
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");
return(NULL);
}
else 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 have 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 */
slot, /* destination 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 it's 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 returned the
* proper number then return, else loop again and
* process more tuples..
******************
*/
current_tuple_count += 1;
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;
RelationInfo *resultRelationInfo;
Relation resultRelationDesc;
int numIndices;
Oid newId;
/******************
* get the heap tuple out of the tuple table slot
******************
*/
tuple = slot->val;
/******************
* get information on the result relation
******************
*/
resultRelationInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelationInfo->ri_RelationDesc;
/******************
* have to add code to preform unique checking here.
* cim -12/1/89
******************
*/
/* BEFORE ROW INSERT Triggers */
if (resultRelationDesc->trigdesc &&
resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
{
HeapTuple newtuple;
newtuple = ExecBRInsertTriggers(resultRelationDesc, tuple);
if (newtuple == NULL) /* "do nothing" */
return;
if (newtuple != tuple) /* modified by Trigger(s) */
{
Assert(slot->ttc_shouldFree);
pfree(tuple);
slot->val = tuple = newtuple;
}
}
/******************
* Check the constraints of a tuple
******************
*/
if (resultRelationDesc->rd_att->constr)
{
ExecConstraints("ExecAppend", resultRelationDesc, tuple, estate);
}
/******************
* insert the tuple
******************
*/
newId = heap_insert(resultRelationDesc, /* relation desc */
tuple); /* heap tuple */
IncrAppended();
/******************
* 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 = resultRelationInfo->ri_NumIndices;
if (numIndices > 0)
ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
(estate->es_processed)++;
estate->es_lastoid = newId;
/* AFTER ROW INSERT Triggers */
if (resultRelationDesc->trigdesc &&
resultRelationDesc->trigdesc->n_after_row[TRIGGER_EVENT_INSERT] > 0)
ExecARInsertTriggers(resultRelationDesc, tuple);
}
/* ----------------------------------------------------------------
* ExecDelete
*
* DELETE is like append, we delete the tuple and its
* index tuples.
* ----------------------------------------------------------------
*/
static void
ExecDelete(TupleTableSlot *slot,
ItemPointer tupleid,
EState *estate)
{
RelationInfo *resultRelationInfo;
Relation resultRelationDesc;
ItemPointerData ctid;
int result;
/******************
* get the result relation information
******************
*/
resultRelationInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelationInfo->ri_RelationDesc;
/* BEFORE ROW DELETE Triggers */
if (resultRelationDesc->trigdesc &&
resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
{
bool dodelete;
dodelete = ExecBRDeleteTriggers(estate, 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,
resultRelationInfo->ri_RangeTableIndex, &ctid);
if (!TupIsNull(epqslot))
{
*tupleid = ctid;
goto ldelete;
}
}
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 (resultRelationDesc->trigdesc &&
resultRelationDesc->trigdesc->n_after_row[TRIGGER_EVENT_DELETE] > 0)
ExecARDeleteTriggers(estate, 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;
RelationInfo *resultRelationInfo;
Relation resultRelationDesc;
ItemPointerData ctid;
int result;
int numIndices;
/******************
* abort the operation if not running transactions
******************
*/
if (IsBootstrapProcessingMode())
{
elog(DEBUG, "ExecReplace: replace can't run without transactions");
return;
}
/******************
* get the heap tuple out of the tuple table slot
******************
*/
tuple = slot->val;
/******************
* get the result relation information
******************
*/
resultRelationInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelationInfo->ri_RelationDesc;
/******************
* have to add code to preform unique checking here.
* in the event of unique tuples, this becomes a deletion
* of the original tuple affected by the replace.
* cim -12/1/89
******************
*/
/* BEFORE ROW UPDATE Triggers */
if (resultRelationDesc->trigdesc &&
resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
{
HeapTuple newtuple;
newtuple = ExecBRUpdateTriggers(estate, tupleid, tuple);
if (newtuple == NULL) /* "do nothing" */
return;
if (newtuple != tuple) /* modified by Trigger(s) */
{
Assert(slot->ttc_shouldFree);
pfree(tuple);
slot->val = tuple = newtuple;
}
}
/******************
* Check the constraints of a tuple
******************
*/
if (resultRelationDesc->rd_att->constr)
{
ExecConstraints("ExecReplace", resultRelationDesc, tuple, estate);
}
/*
* replace the heap tuple
*/
lreplace:;
result = heap_replace(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,
resultRelationInfo->ri_RangeTableIndex, &ctid);
if (!TupIsNull(epqslot))
{
*tupleid = ctid;
tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
slot = ExecStoreTuple(tuple, slot, InvalidBuffer, true);
goto lreplace;
}
}
return;
default:
elog(ERROR, "Unknown status %u from heap_replace", 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 vaccuum deamon.. All we do is insert new
* index tuples. -cim 9/27/89
******************
*/
/******************
* process indices
*
* heap_replace 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 = resultRelationInfo->ri_NumIndices;
if (numIndices > 0)
ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
/* AFTER ROW UPDATE Triggers */
if (resultRelationDesc->trigdesc &&
resultRelationDesc->trigdesc->n_after_row[TRIGGER_EVENT_UPDATE] > 0)
ExecARUpdateTriggers(estate, tupleid, tuple);
}
#if 0
static HeapTuple
ExecAttrDefault(Relation rel, HeapTuple tuple)
{
int ndef = rel->rd_att->constr->num_defval;
AttrDefault *attrdef = rel->rd_att->constr->defval;
ExprContext *econtext = makeNode(ExprContext);
HeapTuple newtuple;
Node *expr;
bool isnull;
bool isdone;
Datum val;
Datum *replValue = NULL;
char *replNull = NULL;
char *repl = NULL;
int i;
econtext->ecxt_scantuple = NULL; /* scan tuple slot */
econtext->ecxt_innertuple = NULL; /* inner tuple slot */
econtext->ecxt_outertuple = NULL; /* outer tuple slot */
econtext->ecxt_relation = NULL; /* relation */
econtext->ecxt_relid = 0; /* relid */
econtext->ecxt_param_list_info = NULL; /* param list info */
econtext->ecxt_param_exec_vals = NULL; /* exec param values */
econtext->ecxt_range_table = NULL; /* range table */
for (i = 0; i < ndef; i++)
{
if (!heap_attisnull(tuple, attrdef[i].adnum))
continue;
expr = (Node *) stringToNode(attrdef[i].adbin);
val = ExecEvalExpr(expr, econtext, &isnull, &isdone);
pfree(expr);
if (isnull)
continue;
if (repl == NULL)
{
repl = (char *) palloc(rel->rd_att->natts * sizeof(char));
replNull = (char *) palloc(rel->rd_att->natts * sizeof(char));
replValue = (Datum *) palloc(rel->rd_att->natts * sizeof(Datum));
MemSet(repl, ' ', rel->rd_att->natts * sizeof(char));
}
repl[attrdef[i].adnum - 1] = 'r';
replNull[attrdef[i].adnum - 1] = ' ';
replValue[attrdef[i].adnum - 1] = val;
}
pfree(econtext);
if (repl == NULL)
return tuple;
newtuple = heap_modifytuple(tuple, rel, replValue, replNull, repl);
pfree(repl);
pfree(tuple);
pfree(replNull);
pfree(replValue);
return newtuple;
}
#endif
static char *
ExecRelCheck(Relation rel, HeapTuple tuple, EState *estate)
{
int ncheck = rel->rd_att->constr->num_check;
ConstrCheck *check = rel->rd_att->constr->check;
ExprContext *econtext = makeNode(ExprContext);
TupleTableSlot *slot = makeNode(TupleTableSlot);
RangeTblEntry *rte = makeNode(RangeTblEntry);
List *rtlist;
List *qual;
bool res;
int i;
slot->val = tuple;
slot->ttc_shouldFree = false;
slot->ttc_descIsNew = true;
slot->ttc_tupleDescriptor = rel->rd_att;
slot->ttc_buffer = InvalidBuffer;
slot->ttc_whichplan = -1;
rte->relname = nameout(&(rel->rd_rel->relname));
rte->refname = rte->relname;
rte->relid = RelationGetRelid(rel);
rte->inh = false;
rte->inFromCl = true;
rtlist = lcons(rte, NIL);
econtext->ecxt_scantuple = slot; /* scan tuple slot */
econtext->ecxt_innertuple = NULL; /* inner tuple slot */
econtext->ecxt_outertuple = NULL; /* outer tuple slot */
econtext->ecxt_relation = rel; /* relation */
econtext->ecxt_relid = 0; /* relid */
econtext->ecxt_param_list_info = NULL; /* param list info */
econtext->ecxt_param_exec_vals = NULL; /* exec param values */
econtext->ecxt_range_table = rtlist; /* range table */
if (estate->es_result_relation_constraints == NULL)
{
estate->es_result_relation_constraints =
(List **)palloc(ncheck * sizeof(List *));
for (i = 0; i < ncheck; i++)
{
qual = (List *) stringToNode(check[i].ccbin);
estate->es_result_relation_constraints[i] = qual;
}
}
for (i = 0; i < ncheck; i++)
{
qual = estate->es_result_relation_constraints[i];
res = ExecQual(qual, econtext);
if (!res)
return check[i].ccname;
}
pfree(slot);
pfree(rte->relname);
pfree(rte);
pfree(rtlist);
pfree(econtext);
return (char *) NULL;
}
void
ExecConstraints(char *caller, Relation rel, HeapTuple tuple, EState *estate)
{
Assert(rel->rd_att->constr);
if (rel->rd_att->constr->has_not_null)
{
int attrChk;
for (attrChk = 1; attrChk <= rel->rd_att->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, rel->rd_att->attrs[attrChk - 1]->attname.data);
}
}
if (rel->rd_att->constr->num_check > 0)
{
char *failed;
if ((failed = ExecRelCheck(rel, tuple, estate)) != NULL)
elog(ERROR, "%s: rejected due to CHECK constraint %s", caller, failed);
}
return;
}
TupleTableSlot*
EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
{
evalPlanQual *epq = (evalPlanQual*) estate->es_evalPlanQual;
evalPlanQual *oldepq;
EState *epqstate = NULL;
Relation relation;
Buffer buffer;
HeapTupleData tuple;
bool endNode = true;
Assert(rti != 0);
if (epq != NULL && epq->rti == 0)
{
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
{
/* 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);
pfree(epqstate->es_evTuple[epq->rti - 1]);
epqstate->es_evTuple[epq->rti - 1] = NULL;
/* push current PQ to freePQ stack */
oldepq->free = epq;
epq = oldepq;
} while (epq->rti != rti);
estate->es_evalPlanQual = (Pointer) epq;
}
/*
* 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));
/* Init EState */
epqstate = &(newepq->estate);
memset(epqstate, 0, sizeof(EState));
epqstate->type = T_EState;
epqstate->es_direction = ForwardScanDirection;
epqstate->es_snapshot = estate->es_snapshot;
epqstate->es_range_table = estate->es_range_table;
epqstate->es_param_list_info = estate->es_param_list_info;
if (estate->es_origPlan->nParamExec > 0)
epqstate->es_param_exec_vals = (ParamExecData *)
palloc(estate->es_origPlan->nParamExec *
sizeof(ParamExecData));
epqstate->es_tupleTable =
ExecCreateTupleTable(estate->es_tupleTable->size);
epqstate->es_refcount = estate->es_refcount;
/* ... rest */
newepq->plan = copyObject(estate->es_origPlan);
newepq->free = NULL;
epqstate->es_evTupleNull = (bool*)
palloc(length(estate->es_range_table) * sizeof(bool));
if (epq == NULL) /* first call */
{
epqstate->es_evTuple = (HeapTuple*)
palloc(length(estate->es_range_table) * sizeof(HeapTuple));
memset(epqstate->es_evTuple, 0,
length(estate->es_range_table) * sizeof(HeapTuple));
}
else
{
epqstate->es_evTuple = epq->estate.es_evTuple;
}
}
else
{
epqstate = &(newepq->estate);
}
/* push current PQ to the stack */
epqstate->es_evalPlanQual = (Pointer) epq;
estate->es_evalPlanQual = (Pointer) epq = newepq;
epq->rti = rti;
endNode = false;
}
epqstate = &(epq->estate);
/*
* Ok - we're requested for the same RTE (-:)).
* I'm not sure about ability to use ExecReScan instead of
* ExecInitNode, so...
*/
if (endNode)
ExecEndNode(epq->plan, epq->plan);
/* free old RTE' tuple */
if (epqstate->es_evTuple[epq->rti - 1] != NULL)
{
pfree(epqstate->es_evTuple[epq->rti - 1]);
epqstate->es_evTuple[epq->rti - 1] = NULL;
}
/* ** fetch tid 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;
foreach (l, estate->es_rowMark)
{
if (((execRowMark*) lfirst(l))->rti == rti)
break;
}
relation = ((execRowMark*) lfirst(l))->relation;
}
tuple.t_self = *tid;
for ( ; ; )
{
heap_fetch(relation, SnapshotDirty, &tuple, &buffer);
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;
}
/*
* Nice! We got tuple - now copy it.
*/
if (epqstate->es_evTuple[epq->rti - 1] != NULL)
pfree(epqstate->es_evTuple[epq->rti - 1]);
epqstate->es_evTuple[epq->rti - 1] = heap_copytuple(&tuple);
ReleaseBuffer(buffer);
break;
}
/*
* Ops! 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))))
{
tuple.t_self = SnapshotDirty->tid; /* updated ... */
continue;
}
/*
* Deleted or updated by this transaction. Do not
* (re-)start execution of this PQ. Continue previous PQ.
*/
oldepq = (evalPlanQual*) epqstate->es_evalPlanQual;
if (oldepq != NULL)
{
Assert(oldepq->rti != 0);
/* push current PQ to freePQ stack */
oldepq->free = epq;
epq = oldepq;
epqstate = &(epq->estate);
estate->es_evalPlanQual = (Pointer) epq;
}
else
{ /* this is the first (oldest) PQ
epq->rti = 0; * - mark as free and
estate->es_useEvalPlan = false; * continue Query execution
return (NULL); */
}
}
if (estate->es_origPlan->nParamExec > 0)
memset(epqstate->es_param_exec_vals, 0,
estate->es_origPlan->nParamExec * sizeof(ParamExecData));
memset(epqstate->es_evTupleNull, false,
length(estate->es_range_table) * sizeof(bool));
ExecInitNode(epq->plan, epqstate, NULL);
/*
* For UPDATE/DELETE we have to return tid of actual row
* we're executing PQ for.
*/
*tid = tuple.t_self;
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))
{
ExecEndNode(epq->plan, epq->plan);
pfree(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)
{ /* this is the first (oldest) */
epq->rti = 0; /* PQ - mark as free and */
estate->es_useEvalPlan = false; /* continue Query execution */
return (NULL);
}
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);
}
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