*/
{
int nSlots = ExecCountSlotsNode(plan);
- TupleTable tupleTable = ExecCreateTupleTable(nSlots + 10); /* why add ten? - jolly */
- estate->es_tupleTable = tupleTable;
+ estate->es_tupleTable = ExecCreateTupleTable(nSlots + 10); /* why add ten? - jolly */
}
+ /* 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
estate->es_into_relation_descriptor = intoRelationDesc;
- estate->es_origPlan = plan;
- estate->es_evalPlanQual = NULL;
- estate->es_evTuple = NULL;
- estate->es_useEvalPlan = false;
-
return tupType;
}
elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
erm->resname);
- /*
- * Unlike the UPDATE/DELETE case, a null result is
- * possible here, when the referenced table is on the
- * nullable side of an outer join. Ignore nulls.
- */
+ /* shouldn't ever get a null result... */
if (isNull)
- continue;
+ elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
+ erm->resname);
tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
test = heap_mark4update(erm->relation, &tuple, &buffer);
/*
* if tuple was deleted or PlanQual failed for
- * updated tuple - we have not return this
+ * updated tuple - we must not return this
* tuple!
*/
goto lnext;
goto ldelete;
}
}
+ /* tuple already deleted; nothing to do */
return;
default:
/*
* 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
*/
-lreplace:;
result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
switch (result)
{
goto lreplace;
}
}
+ /* tuple already deleted; nothing to do */
return;
default:
}
}
+/*
+ * 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 = (evalPlanQual *) estate->es_evalPlanQual;
- evalPlanQual *oldepq;
- EState *epqstate = NULL;
+ evalPlanQual *epq;
+ EState *epqstate;
Relation relation;
- Buffer buffer;
HeapTupleData tuple;
- bool endNode = true;
+ 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);
+ 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;
{
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);
- epqstate->es_tupleTable->next = 0;
+ 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);
- estate->es_evalPlanQual = (Pointer) epq;
}
/*
if (newepq == NULL) /* first call or freePQ stack is empty */
{
newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
- /* Init EState */
+ 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);
- memset(epqstate, 0, sizeof(EState));
- epqstate->type = T_EState;
+ memcpy(epqstate, estate, sizeof(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_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(length(estate->es_range_table) * sizeof(HeapTuple));
- memset(epqstate->es_evTuple, 0,
- length(estate->es_range_table) * sizeof(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;
endNode = false;
}
+ Assert(epq->rti == rti);
epqstate = &(epq->estate);
/*
- * Ok - we're requested for the same RTE (-:)). I'm not sure about
- * ability to use ExecReScan instead of ExecInitNode, so...
+ * 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);
- epqstate->es_tupleTable->next = 0;
+ ExecDropTupleTable(epqstate->es_tupleTable, true);
+ epqstate->es_tupleTable = NULL;
}
- /* 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 */
- }
- }
+ /*
+ * 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,
- length(estate->es_range_table) * sizeof(bool));
- Assert(epqstate->es_tupleTable->next == 0);
- ExecInitNode(epq->plan, epqstate, NULL);
+ 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);
- /*
- * For UPDATE/DELETE we have to return tid of actual row we're
- * executing PQ for.
- */
- *tid = tuple.t_self;
+ ExecInitNode(epq->plan, epqstate, NULL);
return EvalPlanQualNext(estate);
}
*/
if (TupIsNull(slot))
{
+ /* stop execution */
ExecEndNode(epq->plan, epq->plan);
- epqstate->es_tupleTable->next = 0;
+ 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 */
for (;;)
{
+ /* stop execution */
ExecEndNode(epq->plan, epq->plan);
- epqstate->es_tupleTable->next = 0;
+ 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]);
static bool exec_append_initialize_next(Append *node);
+
/* ----------------------------------------------------------------
* exec_append_initialize_next
*
EState *estate;
AppendState *appendstate;
int whichplan;
- int nplans;
/*
* get information from the append node
estate = node->plan.state;
appendstate = node->appendstate;
whichplan = appendstate->as_whichplan;
- nplans = appendstate->as_nplans;
- if (whichplan < 0)
+ if (whichplan < appendstate->as_firstplan)
{
/*
* ExecProcAppend that we are at the end of the line by returning
* FALSE
*/
- appendstate->as_whichplan = 0;
+ appendstate->as_whichplan = appendstate->as_firstplan;
return FALSE;
}
- else if (whichplan >= nplans)
+ else if (whichplan > appendstate->as_lastplan)
{
/*
* as above, end the scan if we go beyond the last scan in our
* list..
*/
- appendstate->as_whichplan = nplans - 1;
+ appendstate->as_whichplan = appendstate->as_lastplan;
return FALSE;
}
else
* structures get allocated in the executor's top level memory
* block instead of that of the call to ExecProcAppend.)
*
- * Returns the scan result of the first scan.
+ * Special case: during an EvalPlanQual recheck query of an inherited
+ * target relation, we only want to initialize and scan the single
+ * subplan that corresponds to the target relation being checked.
* ----------------------------------------------------------------
*/
bool
* create new AppendState for our append node
*/
appendstate = makeNode(AppendState);
- appendstate->as_whichplan = 0;
appendstate->as_nplans = nplans;
appendstate->as_initialized = initialized;
node->appendstate = appendstate;
+ /*
+ * Do we want to scan just one subplan? (Special case for EvalPlanQual)
+ * XXX pretty dirty way of determining that this case applies ...
+ */
+ if (node->isTarget && estate->es_evTuple != NULL)
+ {
+ int tplan;
+
+ tplan = estate->es_result_relation_info - estate->es_result_relations;
+ Assert(tplan >= 0 && tplan < nplans);
+
+ appendstate->as_firstplan = tplan;
+ appendstate->as_lastplan = tplan;
+ }
+ else
+ {
+ /* normal case, scan all subplans */
+ appendstate->as_firstplan = 0;
+ appendstate->as_lastplan = nplans - 1;
+ }
+
/*
* Miscellaneous initialization
*
ExecInitResultTupleSlot(estate, &appendstate->cstate);
/*
- * call ExecInitNode on each of the plans in our list and save the
+ * call ExecInitNode on each of the plans to be executed and save the
* results into the array "initialized"
*/
- for (i = 0; i < nplans; i++)
+ for (i = appendstate->as_firstplan; i <= appendstate->as_lastplan; i++)
{
appendstate->as_whichplan = i;
exec_append_initialize_next(node);
/*
* return the result from the first subplan's initialization
*/
- appendstate->as_whichplan = 0;
+ appendstate->as_whichplan = appendstate->as_firstplan;
exec_append_initialize_next(node);
return TRUE;
ExecReScanAppend(Append *node, ExprContext *exprCtxt, Plan *parent)
{
AppendState *appendstate = node->appendstate;
- int nplans = length(node->appendplans);
int i;
- for (i = 0; i < nplans; i++)
+ for (i = appendstate->as_firstplan; i <= appendstate->as_lastplan; i++)
{
Plan *subnode;
ExecReScan(subnode, exprCtxt, (Plan *) node);
}
}
- appendstate->as_whichplan = 0;
+ appendstate->as_whichplan = appendstate->as_firstplan;
exec_append_initialize_next(node);
}
projects / users / bernd / postgres.git / commitdiff