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postgres/src/backend/executor/execMain.c
Bruce Momjian 5c25d60244 Add: 
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc

to all files copyright Regents of Berkeley.  Man, that's a lot of files.
2000-01-26 05:58:53 +00:00

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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* The old ExecutorMain() has been replaced by ExecutorStart(),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) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.107 2000/01/26 05:56:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/heap.h"
#include "commands/trigger.h"
#include "executor/execdebug.h"
#include "executor/execdefs.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "optimizer/var.h"
#include "parser/parsetree.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/syscache.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 */
/* ----------------------------------------------------------------
* 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);
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);
/* XXX - clean up some more from ExecutorStart() - er1p */
if (NULL == estate->es_snapshot)
{
/* nothing to free */
}
else
{
if (estate->es_snapshot->xcnt > 0)
pfree(estate->es_snapshot->xip);
pfree(estate->es_snapshot);
}
if (NULL == estate->es_param_exec_vals)
{
/* nothing to free */
}
else
{
pfree(estate->es_param_exec_vals);
estate->es_param_exec_vals = NULL;
}
}
void
ExecCheckPerms(CmdType operation,
int resultRelation,
List *rangeTable,
Query *parseTree)
{
int rtindex = 0;
List *lp;
List *qvars,
*tvars;
int32 ok = 1,
aclcheck_result = -1;
char *opstr;
char *relName = NULL;
char *userName;
#define CHECK(MODE) pg_aclcheck(relName, userName, MODE)
userName = GetPgUserName();
foreach(lp, rangeTable)
{
RangeTblEntry *rte = lfirst(lp);
++rtindex;
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;
}
relName = rte->relname;
if (rtindex == 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;
}
if (!ok)
elog(ERROR, "%s: %s", relName, 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;
relName = rt_fetch(rm->rti, rangeTable)->relname;
ok = ((aclcheck_result = CHECK(ACL_WR)) == ACLCHECK_OK);
opstr = "write";
if (!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;
int resultRelation;
Relation intoRelationDesc;
TupleDesc tupType;
List *targetList;
/*
* 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, RowExclusiveLock);
if (resultRelationDesc->rd_rel->relkind == RELKIND_SEQUENCE)
elog(ERROR, "You can't change sequence relation %s",
RelationGetRelationName(resultRelationDesc));
resultRelationInfo = makeNode(RelationInfo);
resultRelationInfo->ri_RangeTableIndex = resultRelationIndex;
resultRelationInfo->ri_RelationDesc = resultRelationDesc;
resultRelationInfo->ri_NumIndices = 0;
resultRelationInfo->ri_IndexRelationDescs = NULL;
resultRelationInfo->ri_IndexRelationInfo = 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(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 = rt_fetch(rm->rti, rangeTable)->relid;
relation = heap_open(relid, 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;
/*
* Now that we have the target list, 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, 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)
{
JunkFilter *j = ExecInitJunkFilter(targetList, tupType);
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);
/*
* Advance command counter so that the newly-created
* relation's catalog tuples will be visible to heap_open.
*/
CommandCounterIncrement();
intoRelationDesc = heap_open(intoRelationId,
AccessExclusiveLock);
}
}
}
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;
ExecDropTupleTable(tupleTable, true);
estate->es_tupleTable = NULL;
}
/*
* close the result relations if necessary,
* but hold locks on them until xact commit
*/
if (resultRelationInfo != NULL)
{
Relation resultRelationDesc;
resultRelationDesc = resultRelationInfo->ri_RelationDesc;
heap_close(resultRelationDesc, NoLock);
/*
* close indices on the result relation
*/
ExecCloseIndices(resultRelationInfo);
}
/*
* close the "into" relation if necessary
*/
if (intoRelationDesc != NULL)
heap_close(intoRelationDesc, NoLock);
}
/* ----------------------------------------------------------------
* 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 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 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);
heap_freetuple(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)
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)
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);
heap_freetuple(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_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,
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_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 vaccuum
* deamon.. 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 = resultRelationInfo->ri_NumIndices;
if (numIndices > 0)
ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
/* AFTER ROW UPDATE Triggers */
if (resultRelationDesc->trigdesc)
ExecARUpdateTriggers(estate, tupleid, tuple);
}
#ifdef NOT_USED
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);
heap_freetuple(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;
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 = RelationGetRelationName(rel);
rte->refname = rte->relname;
rte->relid = RelationGetRelid(rel);
/* inh, inFromCl, inJoinSet, skipAcl won't be used, leave them zero */
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];
/*
* 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;
}
pfree(slot);
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, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
}
}
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);
epqstate->es_tupleTable->next = 0;
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;
} 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);
/* ... 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;
epq = newepq;
estate->es_evalPlanQual = (Pointer) epq;
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);
epqstate->es_tupleTable->next = 0;
}
/* free old RTE' tuple */
if (epqstate->es_evTuple[epq->rti - 1] != NULL)
{
heap_freetuple(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(NOTICE, "EvalPlanQual: t_xmin is uncommitted ?!");
Assert(!TransactionIdIsValid(SnapshotDirty->xmin));
elog(ERROR, "Aborting this transaction");
}
/*
* 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)
heap_freetuple(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
{
epq->rti = 0; /* this is the first (oldest) */
estate->es_useEvalPlan = false; /* PQ - mark as free and */
return (NULL); /* continue Query execution */
}
}
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));
Assert(epqstate->es_tupleTable->next == 0);
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);
epqstate->es_tupleTable->next = 0;
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);
}
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