/* ----------------------------------------------------------------
* ExecUnique
* ----------------------------------------------------------------
*/
TupleTableSlot * /* return: a tuple or NULL */
ExecUnique(UniqueState *node)
{
Unique *plannode = (Unique *) node->ps.plan;
TupleTableSlot *resultTupleSlot;
TupleTableSlot *slot;
PlanState *outerPlan;
/*
* get information from the node
*/
outerPlan = outerPlanState(node);
resultTupleSlot = node->ps.ps_ResultTupleSlot;
/*
* now loop, returning only non-duplicate tuples. We assume that the
* tuples arrive in sorted order so we can detect duplicates easily. The
* first tuple of each group is returned.
*/
for (;;)
{
/*
* fetch a tuple from the outer subplan
*/
slot = ExecProcNode(outerPlan);
if (TupIsNull(slot))
{
/* end of subplan, so we're done */
ExecClearTuple(resultTupleSlot);
return NULL;
}
/*
* Always return the first tuple from the subplan.
*/
if (TupIsNull(resultTupleSlot))
break;
/*
* Else test if the new tuple and the previously returned tuple match.
* If so then we loop back and fetch another new tuple from the
* subplan.
*/
if (!execTuplesMatch(slot, resultTupleSlot,
plannode->numCols, plannode->uniqColIdx,
node->eqfunctions,
node->tempContext))
break;
}
/*
* We have a new tuple different from the previous saved tuple (if any).
* Save it and return it. We must copy it because the source subplan
* won't guarantee that this source tuple is still accessible after
* fetching the next source tuple.
*/
return ExecCopySlot(resultTupleSlot, slot);
}
TupleTableSlot *
ExecTwice(TwiceState *node) {
TupleTableSlot *resultTupleSlot;
TupleTableSlot *slot;
PlanState *outerPlan;
/*
* get information from the node
*/
outerPlan = outerPlanState(node);
resultTupleSlot = node->ps.ps_ResultTupleSlot;
/*
* Fetch a tuple from outer plan, and make it a result tuple.
*/
if(node->isFirst)
{
/*
* fetch a tuple from the outer subplan
*/
slot = ExecProcNode(outerPlan);
if (TupIsNull(slot))
{
/* end of subplan, so we're done */
ExecClearTuple(resultTupleSlot);
return NULL;
}
node->isFirst = false;
return ExecCopySlot(resultTupleSlot, slot);
}
/*
* If we used the current tuple already, copy it a second time. Do not
* proceed to the next tuple.
*/
node->isFirst = true;
return ExecCopySlot(resultTupleSlot, resultTupleSlot);
}
/* ----------------------------------------------------------------
* ExecMaterial
*
* As long as we are at the end of the data collected in the tuplestore,
* we collect one new row from the subplan on each call, and stash it
* aside in the tuplestore before returning it. The tuplestore is
* only read if we are asked to scan backwards, rescan, or mark/restore.
*
* ----------------------------------------------------------------
*/
TupleTableSlot * /* result tuple from subplan */
ExecMaterial(MaterialState *node)
{
EState *estate;
ScanDirection dir;
bool forward;
NTupleStore *ts;
NTupleStoreAccessor *tsa;
bool eof_tuplestore;
TupleTableSlot *slot;
Material *ma;
/*
* get state info from node
*/
estate = node->ss.ps.state;
dir = estate->es_direction;
forward = ScanDirectionIsForward(dir);
ts = node->ts_state->matstore;
tsa = (NTupleStoreAccessor *) node->ts_pos;
ma = (Material *) node->ss.ps.plan;
Assert(IsA(ma, Material));
/*
* If first time through, and we need a tuplestore, initialize it.
*/
if (ts == NULL && (ma->share_type != SHARE_NOTSHARED || node->randomAccess))
{
/*
* For cross slice material, we only run ExecMaterial on DriverSlice
*/
if(ma->share_type == SHARE_MATERIAL_XSLICE)
{
char rwfile_prefix[100];
if(ma->driver_slice != currentSliceId)
{
elog(LOG, "Material Exec on CrossSlice, current slice %d", currentSliceId);
return NULL;
}
shareinput_create_bufname_prefix(rwfile_prefix, sizeof(rwfile_prefix), ma->share_id);
elog(LOG, "Material node creates shareinput rwfile %s", rwfile_prefix);
ts = ntuplestore_create_readerwriter(rwfile_prefix, PlanStateOperatorMemKB((PlanState *)node) * 1024, true);
tsa = ntuplestore_create_accessor(ts, true);
}
else
{
/* Non-shared Materialize node */
bool isWriter = true;
workfile_set *work_set = NULL;
if (gp_workfile_caching)
{
work_set = workfile_mgr_find_set( &node->ss.ps);
if (NULL != work_set)
{
/* Reusing cached workfiles. Tell subplan we won't be needing any tuples */
elog(gp_workfile_caching_loglevel, "Materialize reusing cached workfiles, initiating Squelch walker");
isWriter = false;
ExecSquelchNode(outerPlanState(node));
node->eof_underlying = true;
node->cached_workfiles_found = true;
if (node->ss.ps.instrument)
{
node->ss.ps.instrument->workfileReused = true;
}
}
}
if (NULL == work_set)
{
/*
* No work_set found, this is because:
* a. workfile caching is enabled but we didn't find any reusable set
* b. workfile caching is disabled
* Creating new empty workset
*/
Assert(!node->cached_workfiles_found);
/* Don't try to cache when running under a ShareInputScan node */
bool can_reuse = (ma->share_type == SHARE_NOTSHARED);
work_set = workfile_mgr_create_set(BUFFILE, can_reuse, &node->ss.ps, NULL_SNAPSHOT);
isWriter = true;
}
Assert(NULL != work_set);
AssertEquivalent(node->cached_workfiles_found, !isWriter);
ts = ntuplestore_create_workset(work_set, node->cached_workfiles_found,
PlanStateOperatorMemKB((PlanState *) node) * 1024);
tsa = ntuplestore_create_accessor(ts, isWriter);
}
Assert(ts && tsa);
node->ts_state->matstore = ts;
node->ts_pos = (void *) tsa;
/* CDB: Offer extra info for EXPLAIN ANALYZE. */
if (node->ss.ps.instrument)
{
/* Let the tuplestore share our Instrumentation object. */
ntuplestore_setinstrument(ts, node->ss.ps.instrument);
/* Request a callback at end of query. */
node->ss.ps.cdbexplainfun = ExecMaterialExplainEnd;
}
/*
* MPP: If requested, fetch all rows from subplan and put them
* in the tuplestore. This decouples a middle slice's receiving
* and sending Motion operators to neutralize a deadlock hazard.
* MPP TODO: Remove when a better solution is implemented.
*
* ShareInput: if the material node
* is used to share input, we will need to fetch all rows and put
* them in tuple store
*/
while (((Material *) node->ss.ps.plan)->cdb_strict
|| ma->share_type != SHARE_NOTSHARED)
{
/*
* When reusing cached workfiles, we already have all the tuples,
* and we don't need to read anything from subplan.
*/
if (node->cached_workfiles_found)
{
break;
}
TupleTableSlot *outerslot = ExecProcNode(outerPlanState(node));
if (TupIsNull(outerslot))
{
node->eof_underlying = true;
if (ntuplestore_created_reusable_workfiles(ts))
{
ntuplestore_flush(ts);
ntuplestore_mark_workset_complete(ts);
}
ntuplestore_acc_seek_bof(tsa);
break;
}
Gpmon_M_Incr(GpmonPktFromMaterialState(node), GPMON_QEXEC_M_ROWSIN);
ntuplestore_acc_put_tupleslot(tsa, outerslot);
}
CheckSendPlanStateGpmonPkt(&node->ss.ps);
if(forward)
ntuplestore_acc_seek_bof(tsa);
else
ntuplestore_acc_seek_eof(tsa);
/* for share input, material do not need to return any tuple */
if(ma->share_type != SHARE_NOTSHARED)
{
Assert(ma->share_type == SHARE_MATERIAL || ma->share_type == SHARE_MATERIAL_XSLICE);
/*
* if the material is shared across slice, notify consumers that
* it is ready.
*/
if(ma->share_type == SHARE_MATERIAL_XSLICE)
{
if (ma->driver_slice == currentSliceId)
{
ntuplestore_flush(ts);
node->share_lk_ctxt = shareinput_writer_notifyready(ma->share_id, ma->nsharer_xslice,
estate->es_plannedstmt->planGen);
}
}
return NULL;
}
}
if(ma->share_type != SHARE_NOTSHARED)
return NULL;
/*
* If we can fetch another tuple from the tuplestore, return it.
*/
slot = node->ss.ps.ps_ResultTupleSlot;
if(forward)
eof_tuplestore = (tsa == NULL) || !ntuplestore_acc_advance(tsa, 1);
else
eof_tuplestore = (tsa == NULL) || !ntuplestore_acc_advance(tsa, -1);
if(tsa!=NULL && ntuplestore_acc_tell(tsa, NULL))
{
ntuplestore_acc_current_tupleslot(tsa, slot);
if (!TupIsNull(slot))
{
Gpmon_M_Incr_Rows_Out(GpmonPktFromMaterialState(node));
CheckSendPlanStateGpmonPkt(&node->ss.ps);
}
return slot;
}
/*
* If necessary, try to fetch another row from the subplan.
*
* Note: the eof_underlying state variable exists to short-circuit further
* subplan calls. It's not optional, unfortunately, because some plan
* node types are not robust about being called again when they've already
* returned NULL.
* If reusing cached workfiles, there is no need to execute subplan at all.
*/
if (eof_tuplestore && !node->eof_underlying)
{
PlanState *outerNode;
TupleTableSlot *outerslot;
Assert(!node->cached_workfiles_found && "we shouldn't get here when using cached workfiles");
/*
* We can only get here with forward==true, so no need to worry about
* which direction the subplan will go.
*/
outerNode = outerPlanState(node);
outerslot = ExecProcNode(outerNode);
if (TupIsNull(outerslot))
{
node->eof_underlying = true;
if (ntuplestore_created_reusable_workfiles(ts))
{
ntuplestore_flush(ts);
ntuplestore_mark_workset_complete(ts);
}
if (!node->ss.ps.delayEagerFree)
{
ExecEagerFreeMaterial(node);
}
return NULL;
}
Gpmon_M_Incr(GpmonPktFromMaterialState(node), GPMON_QEXEC_M_ROWSIN);
if (tsa)
ntuplestore_acc_put_tupleslot(tsa, outerslot);
/*
* And return a copy of the tuple. (XXX couldn't we just return the
* outerslot?)
*/
Gpmon_M_Incr_Rows_Out(GpmonPktFromMaterialState(node));
CheckSendPlanStateGpmonPkt(&node->ss.ps);
return ExecCopySlot(slot, outerslot);
}
if (!node->ss.ps.delayEagerFree)
{
ExecEagerFreeMaterial(node);
}
/*
* Nothing left ...
*/
return NULL;
}
/* ----------------------------------------------------------------
* CteScanNext
*
* This is a workhorse for ExecCteScan
* ----------------------------------------------------------------
*/
static TupleTableSlot *
CteScanNext(CteScanState *node)
{
EState *estate;
ScanDirection dir;
bool forward;
Tuplestorestate *tuplestorestate;
bool eof_tuplestore;
TupleTableSlot *slot;
/*
* get state info from node
*/
estate = node->ss.ps.state;
dir = estate->es_direction;
forward = ScanDirectionIsForward(dir);
tuplestorestate = node->leader->cte_table;
tuplestore_select_read_pointer(tuplestorestate, node->readptr);
slot = node->ss.ss_ScanTupleSlot;
/*
* If we are not at the end of the tuplestore, or are going backwards, try
* to fetch a tuple from tuplestore.
*/
eof_tuplestore = tuplestore_ateof(tuplestorestate);
if (!forward && eof_tuplestore)
{
if (!node->leader->eof_cte)
{
/*
* When reversing direction at tuplestore EOF, the first
* gettupleslot call will fetch the last-added tuple; but we want
* to return the one before that, if possible. So do an extra
* fetch.
*/
if (!tuplestore_advance(tuplestorestate, forward))
return NULL; /* the tuplestore must be empty */
}
eof_tuplestore = false;
}
/*
* If we can fetch another tuple from the tuplestore, return it.
*
* Note: we have to use copy=true in the tuplestore_gettupleslot call,
* because we are sharing the tuplestore with other nodes that might write
* into the tuplestore before we get called again.
*/
if (!eof_tuplestore)
{
if (tuplestore_gettupleslot(tuplestorestate, forward, true, slot))
return slot;
if (forward)
eof_tuplestore = true;
}
/*
* If necessary, try to fetch another row from the CTE query.
*
* Note: the eof_cte state variable exists to short-circuit further calls
* of the CTE plan. It's not optional, unfortunately, because some plan
* node types are not robust about being called again when they've already
* returned NULL.
*/
if (eof_tuplestore && !node->leader->eof_cte)
{
TupleTableSlot *cteslot;
/*
* We can only get here with forward==true, so no need to worry about
* which direction the subplan will go.
*/
cteslot = ExecProcNode(node->cteplanstate);
if (TupIsNull(cteslot))
{
node->leader->eof_cte = true;
return NULL;
}
/*
* There are corner cases where the subplan could change which
* tuplestore read pointer is active, so be sure to reselect ours
* before storing the tuple we got.
*/
tuplestore_select_read_pointer(tuplestorestate, node->readptr);
/*
* Append a copy of the returned tuple to tuplestore. NOTE: because
* our read pointer is certainly in EOF state, its read position will
* move forward over the added tuple. This is what we want. Also,
* any other readers will *not* move past the new tuple, which is what
* they want.
*/
tuplestore_puttupleslot(tuplestorestate, cteslot);
/*
* We MUST copy the CTE query's output tuple into our own slot. This
* is because other CteScan nodes might advance the CTE query before
* we are called again, and our output tuple must stay stable over
* that.
*/
return ExecCopySlot(slot, cteslot);
}
/*
* Nothing left ...
*/
return ExecClearTuple(slot);
}
/* ----------------------------------------------------------------
* ExecSetOp
* ----------------------------------------------------------------
*/
TupleTableSlot * /* return: a tuple or NULL */
ExecSetOp(SetOpState *node)
{
SetOp *plannode = (SetOp *) node->ps.plan;
TupleTableSlot *resultTupleSlot;
PlanState *outerPlan;
/*
* get information from the node
*/
outerPlan = outerPlanState(node);
resultTupleSlot = node->ps.ps_ResultTupleSlot;
/*
* If the previously-returned tuple needs to be returned more than once,
* keep returning it.
*/
if (node->numOutput > 0)
{
node->numOutput--;
return resultTupleSlot;
}
/* Flag that we have no current tuple */
ExecClearTuple(resultTupleSlot);
/*
* Absorb groups of duplicate tuples, counting them, and saving the first
* of each group as a possible return value. At the end of each group,
* decide whether to return anything.
*
* We assume that the tuples arrive in sorted order so we can detect
* duplicates easily.
*/
for (;;)
{
TupleTableSlot *inputTupleSlot;
bool endOfGroup;
/*
* fetch a tuple from the outer subplan, unless we already did.
*/
if (node->ps.ps_OuterTupleSlot == NULL &&
!node->subplan_done)
{
node->ps.ps_OuterTupleSlot =
ExecProcNode(outerPlan);
if (TupIsNull(node->ps.ps_OuterTupleSlot))
node->subplan_done = true;
}
inputTupleSlot = node->ps.ps_OuterTupleSlot;
if (TupIsNull(resultTupleSlot))
{
/*
* First of group: save a copy in result slot, and reset
* duplicate-counters for new group.
*/
if (node->subplan_done)
return NULL; /* no more tuples */
ExecCopySlot(resultTupleSlot, inputTupleSlot);
node->numLeft = 0;
node->numRight = 0;
endOfGroup = false;
}
else if (node->subplan_done)
{
/*
* Reached end of input, so finish processing final group
*/
endOfGroup = true;
}
else
{
/*
* Else test if the new tuple and the previously saved tuple
* match.
*/
if (execTuplesMatch(inputTupleSlot,
resultTupleSlot,
plannode->numCols, plannode->dupColIdx,
node->eqfunctions,
node->tempContext))
endOfGroup = false;
else
endOfGroup = true;
}
if (endOfGroup)
{
/*
* We've reached the end of the group containing resultTuple.
* Decide how many copies (if any) to emit. This logic is
* straight from the SQL92 specification.
*/
switch (plannode->cmd)
{
case SETOPCMD_INTERSECT:
if (node->numLeft > 0 && node->numRight > 0)
node->numOutput = 1;
else
node->numOutput = 0;
break;
case SETOPCMD_INTERSECT_ALL:
node->numOutput =
(node->numLeft < node->numRight) ?
node->numLeft : node->numRight;
break;
case SETOPCMD_EXCEPT:
if (node->numLeft > 0 && node->numRight == 0)
node->numOutput = 1;
else
node->numOutput = 0;
break;
case SETOPCMD_EXCEPT_ALL:
node->numOutput =
(node->numLeft < node->numRight) ?
0 : (node->numLeft - node->numRight);
break;
default:
elog(ERROR, "unrecognized set op: %d",
(int) plannode->cmd);
break;
}
/* Fall out of for-loop if we have tuples to emit */
if (node->numOutput > 0)
break;
/* Else flag that we have no current tuple, and loop around */
ExecClearTuple(resultTupleSlot);
}
else
{
/*
* Current tuple is member of same group as resultTuple. Count it
* in the appropriate counter.
*/
int flag;
bool isNull;
flag = DatumGetInt32(slot_getattr(inputTupleSlot,
plannode->flagColIdx,
&isNull));
Assert(!isNull);
if (flag)
node->numRight++;
else
node->numLeft++;
/* Set flag to fetch a new input tuple, and loop around */
node->ps.ps_OuterTupleSlot = NULL;
}
}
/*
* If we fall out of loop, then we need to emit at least one copy of
* resultTuple.
*/
Assert(node->numOutput > 0);
node->numOutput--;
return resultTupleSlot;
}
/*
* ExecGroup -
*
* Return one tuple for each group of matching input tuples.
*/
TupleTableSlot *
ExecGroup(GroupState *node)
{
ExprContext *econtext;
int numCols;
AttrNumber *grpColIdx;
TupleTableSlot *firsttupleslot;
TupleTableSlot *outerslot;
/*
* get state info from node
*/
if (node->grp_done)
return NULL;
econtext = node->ss.ps.ps_ExprContext;
numCols = ((Group *) node->ss.ps.plan)->numCols;
grpColIdx = ((Group *) node->ss.ps.plan)->grpColIdx;
/*
* The ScanTupleSlot holds the (copied) first tuple of each group.
*/
firsttupleslot = node->ss.ss_ScanTupleSlot;
/*
* We need not call ResetExprContext here because execTuplesMatch will
* reset the per-tuple memory context once per input tuple.
*/
/*
* If first time through, acquire first input tuple and determine whether
* to return it or not.
*/
if (TupIsNull(firsttupleslot))
{
outerslot = ExecProcNode(outerPlanState(node));
if (TupIsNull(outerslot))
{
/* empty input, so return nothing */
node->grp_done = TRUE;
return NULL;
}
/* Copy tuple, set up as input for qual test and projection */
ExecCopySlot(firsttupleslot, outerslot);
econtext->ecxt_scantuple = firsttupleslot;
/*
* Check the qual (HAVING clause); if the group does not match, ignore
* it and fall into scan loop.
*/
if (ExecQual(node->ss.ps.qual, econtext, false))
{
/*
* Form and return a projection tuple using the first input tuple.
*/
return ExecProject(node->ss.ps.ps_ProjInfo, NULL);
}
}
/*
* This loop iterates once per input tuple group. At the head of the
* loop, we have finished processing the first tuple of the group and now
* need to scan over all the other group members.
*/
for (;;)
{
/*
* Scan over all remaining tuples that belong to this group
*/
for (;;)
{
outerslot = ExecProcNode(outerPlanState(node));
if (TupIsNull(outerslot))
{
/* no more groups, so we're done */
node->grp_done = TRUE;
return NULL;
}
/*
* Compare with first tuple and see if this tuple is of the same
* group. If so, ignore it and keep scanning.
*/
if (!execTuplesMatch(firsttupleslot, outerslot,
numCols, grpColIdx,
node->eqfunctions,
econtext->ecxt_per_tuple_memory))
break;
}
/*
* We have the first tuple of the next input group. See if we want to
* return it.
*/
/* Copy tuple, set up as input for qual test and projection */
ExecCopySlot(firsttupleslot, outerslot);
econtext->ecxt_scantuple = firsttupleslot;
/*
* Check the qual (HAVING clause); if the group does not match, ignore
* it and loop back to scan the rest of the group.
*/
if (ExecQual(node->ss.ps.qual, econtext, false))
{
/*
* Form and return a projection tuple using the first input tuple.
*/
return ExecProject(node->ss.ps.ps_ProjInfo, NULL);
}
}
/* NOTREACHED */
return NULL;
}
/* ----------------------------------------------------------------
* ExecMaterial
*
* As long as we are at the end of the data collected in the tuplestore,
* we collect one new row from the subplan on each call, and stash it
* aside in the tuplestore before returning it. The tuplestore is
* only read if we are asked to scan backwards, rescan, or mark/restore.
*
* ----------------------------------------------------------------
*/
static TupleTableSlot * /* result tuple from subplan */
ExecMaterial(PlanState *pstate)
{
MaterialState *node = castNode(MaterialState, pstate);
EState *estate;
ScanDirection dir;
bool forward;
Tuplestorestate *tuplestorestate;
bool eof_tuplestore;
TupleTableSlot *slot;
CHECK_FOR_INTERRUPTS();
/*
* get state info from node
*/
estate = node->ss.ps.state;
dir = estate->es_direction;
forward = ScanDirectionIsForward(dir);
tuplestorestate = node->tuplestorestate;
/*
* If first time through, and we need a tuplestore, initialize it.
*/
if (tuplestorestate == NULL && node->eflags != 0)
{
tuplestorestate = tuplestore_begin_heap(true, false, work_mem);
tuplestore_set_eflags(tuplestorestate, node->eflags);
if (node->eflags & EXEC_FLAG_MARK)
{
/*
* Allocate a second read pointer to serve as the mark. We know it
* must have index 1, so needn't store that.
*/
int ptrno PG_USED_FOR_ASSERTS_ONLY;
ptrno = tuplestore_alloc_read_pointer(tuplestorestate,
node->eflags);
Assert(ptrno == 1);
}
node->tuplestorestate = tuplestorestate;
}
/*
* If we are not at the end of the tuplestore, or are going backwards, try
* to fetch a tuple from tuplestore.
*/
eof_tuplestore = (tuplestorestate == NULL) ||
tuplestore_ateof(tuplestorestate);
if (!forward && eof_tuplestore)
{
if (!node->eof_underlying)
{
/*
* When reversing direction at tuplestore EOF, the first
* gettupleslot call will fetch the last-added tuple; but we want
* to return the one before that, if possible. So do an extra
* fetch.
*/
if (!tuplestore_advance(tuplestorestate, forward))
return NULL; /* the tuplestore must be empty */
}
eof_tuplestore = false;
}
/*
* If we can fetch another tuple from the tuplestore, return it.
*/
slot = node->ss.ps.ps_ResultTupleSlot;
if (!eof_tuplestore)
{
if (tuplestore_gettupleslot(tuplestorestate, forward, false, slot))
return slot;
if (forward)
eof_tuplestore = true;
}
/*
* If necessary, try to fetch another row from the subplan.
*
* Note: the eof_underlying state variable exists to short-circuit further
* subplan calls. It's not optional, unfortunately, because some plan
* node types are not robust about being called again when they've already
* returned NULL.
*/
if (eof_tuplestore && !node->eof_underlying)
{
PlanState *outerNode;
TupleTableSlot *outerslot;
/*
* We can only get here with forward==true, so no need to worry about
* which direction the subplan will go.
*/
outerNode = outerPlanState(node);
outerslot = ExecProcNode(outerNode);
if (TupIsNull(outerslot))
{
node->eof_underlying = true;
return NULL;
}
/*
* Append a copy of the returned tuple to tuplestore. NOTE: because
* the tuplestore is certainly in EOF state, its read position will
* move forward over the added tuple. This is what we want.
*/
if (tuplestorestate)
tuplestore_puttupleslot(tuplestorestate, outerslot);
ExecCopySlot(slot, outerslot);
return slot;
}
/*
* Nothing left ...
*/
return ExecClearTuple(slot);
}
/*
* ExecGroup -
*
* Return one tuple for each group of matching input tuples.
*/
TupleTableSlot *
ExecGroup(GroupState *node)
{
ExprContext *econtext;
int numCols;
AttrNumber *grpColIdx;
TupleTableSlot *firsttupleslot;
TupleTableSlot *outerslot;
/*
* get state info from node
*/
if (node->grp_done)
return NULL;
econtext = node->ss.ps.ps_ExprContext;
numCols = ((Group *) node->ss.ps.plan)->numCols;
grpColIdx = ((Group *) node->ss.ps.plan)->grpColIdx;
/*
* Check to see if we're still projecting out tuples from a previous group
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->ss.ps.ps_TupFromTlist)
{
TupleTableSlot *result;
ExprDoneCond isDone;
result = ExecProject(node->ss.ps.ps_ProjInfo, &isDone);
if (isDone == ExprMultipleResult)
return result;
/* Done with that source tuple... */
node->ss.ps.ps_TupFromTlist = false;
}
/*
* The ScanTupleSlot holds the (copied) first tuple of each group.
*/
firsttupleslot = node->ss.ss_ScanTupleSlot;
/*
* We need not call ResetExprContext here because execTuplesMatch will
* reset the per-tuple memory context once per input tuple.
*/
/*
* If first time through, acquire first input tuple and determine whether
* to return it or not.
*/
if (TupIsNull(firsttupleslot))
{
outerslot = ExecProcNode(outerPlanState(node));
if (TupIsNull(outerslot))
{
/* empty input, so return nothing */
node->grp_done = TRUE;
return NULL;
}
/* Copy tuple into firsttupleslot */
ExecCopySlot(firsttupleslot, outerslot);
/*
* Set it up as input for qual test and projection. The expressions
* will access the input tuple as varno OUTER.
*/
econtext->ecxt_outertuple = firsttupleslot;
/*
* Check the qual (HAVING clause); if the group does not match, ignore
* it and fall into scan loop.
*/
if (ExecQual(node->ss.ps.qual, econtext, false))
{
/*
* Form and return a projection tuple using the first input tuple.
*/
TupleTableSlot *result;
ExprDoneCond isDone;
result = ExecProject(node->ss.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->ss.ps.ps_TupFromTlist = (isDone == ExprMultipleResult);
return result;
}
}
else
InstrCountFiltered1(node, 1);
}
/*
* This loop iterates once per input tuple group. At the head of the
* loop, we have finished processing the first tuple of the group and now
* need to scan over all the other group members.
*/
for (;;)
{
/*
* Scan over all remaining tuples that belong to this group
*/
for (;;)
{
outerslot = ExecProcNode(outerPlanState(node));
if (TupIsNull(outerslot))
{
/* no more groups, so we're done */
node->grp_done = TRUE;
return NULL;
}
/*
* Compare with first tuple and see if this tuple is of the same
* group. If so, ignore it and keep scanning.
*/
if (!execTuplesMatch(firsttupleslot, outerslot,
numCols, grpColIdx,
node->eqfunctions,
econtext->ecxt_per_tuple_memory))
break;
}
/*
* We have the first tuple of the next input group. See if we want to
* return it.
*/
/* Copy tuple, set up as input for qual test and projection */
ExecCopySlot(firsttupleslot, outerslot);
econtext->ecxt_outertuple = firsttupleslot;
/*
* Check the qual (HAVING clause); if the group does not match, ignore
* it and loop back to scan the rest of the group.
*/
if (ExecQual(node->ss.ps.qual, econtext, false))
{
/*
* Form and return a projection tuple using the first input tuple.
*/
TupleTableSlot *result;
ExprDoneCond isDone;
result = ExecProject(node->ss.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->ss.ps.ps_TupFromTlist = (isDone == ExprMultipleResult);
return result;
}
}
else
InstrCountFiltered1(node, 1);
}
}
