/*
* ForeignRecheck -- access method routine to recheck a tuple in EvalPlanQual
*/
static bool
ForeignRecheck(ForeignScanState *node, TupleTableSlot *slot)
{
FdwRoutine *fdwroutine = node->fdwroutine;
ExprContext *econtext;
/*
* extract necessary information from foreign scan node
*/
econtext = node->ss.ps.ps_ExprContext;
/* Does the tuple meet the remote qual condition? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
/*
* If an outer join is pushed down, RecheckForeignScan may need to store a
* different tuple in the slot, because a different set of columns may go
* to NULL upon recheck. Otherwise, it shouldn't need to change the slot
* contents, just return true or false to indicate whether the quals still
* pass. For simple cases, setting fdw_recheck_quals may be easier than
* providing this callback.
*/
if (fdwroutine->RecheckForeignScan &&
!fdwroutine->RecheckForeignScan(node, slot))
return false;
return ExecQual(node->fdw_recheck_quals, econtext, false);
}
/*
* IndexRecheck -- access method routine to recheck a tuple in EvalPlanQual
*/
static bool
IndexRecheck(IndexScanState *node, TupleTableSlot *slot)
{
ExprContext *econtext;
/*
* extract necessary information from index scan node
*/
econtext = node->ss.ps.ps_ExprContext;
/* Does the tuple meet the indexqual condition? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
return ExecQual(node->indexqualorig, econtext, false);
}
/*
* BitmapHeapRecheck -- access method routine to recheck a tuple in EvalPlanQual
*/
static bool
BitmapHeapRecheck(BitmapHeapScanState *node, TupleTableSlot *slot)
{
ExprContext *econtext;
/*
* extract necessary information from index scan node
*/
econtext = node->ss.ps.ps_ExprContext;
/* Does the tuple meet the original qual conditions? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
return ExecQual(node->bitmapqualorig, econtext);
}
static TupleTableSlot*
BitmapTableScanPlanQualTuple(BitmapTableScanState *node)
{
EState *estate = node->ss.ps.state;
Index scanrelid = ((BitmapTableScan *) node->ss.ps.plan)->scan.scanrelid;
ExprContext *econtext = node->ss.ps.ps_ExprContext;
TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
/*
* Check if we are evaluating PlanQual for tuple of this relation.
* Additional checking is not good, but no other way for now. We could
* introduce new nodes for this case and handle IndexScan --> NewNode
* switching in Init/ReScan plan...
*/
if (estate->es_evTuple != NULL &&
estate->es_evTuple[scanrelid - 1] != NULL)
{
if (estate->es_evTupleNull[scanrelid - 1])
{
return ExecClearTuple(slot);
}
ExecStoreGenericTuple(estate->es_evTuple[scanrelid - 1], slot, false);
/* Does the tuple meet the original qual conditions? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext, false))
{
ExecClearTuple(slot); /* would not be returned by scan */
}
/* Flag for the next call that no more tuples */
estate->es_evTupleNull[scanrelid - 1] = true;
return slot;
}
return ExecClearTuple(slot);
}
/*
* Checks eligibility of a tuple.
*
* Note, a tuple may fail to meet visibility requirement. Moreover,
* for a lossy bitmap, we need to check for every tuple to make sure
* that it satisfies the qual.
*/
bool
BitmapTableScanRecheckTuple(BitmapTableScanState *scanState, TupleTableSlot *slot)
{
/*
* If we are using lossy info or we are required to recheck each tuple
* because of visibility or other causes, then evaluate the tuple
* eligibility.
*/
if (scanState->isLossyBitmapPage || scanState->recheckTuples)
{
ExprContext *econtext = scanState->ss.ps.ps_ExprContext;
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
return ExecQual(scanState->bitmapqualorig, econtext, false);
}
return true;
}
/* ----------------------------------------------------------------
* ExecScan
*
* Scans the relation using the 'access method' indicated and
* returns the next qualifying tuple in the direction specified
* in the global variable ExecDirection.
* The access method returns the next tuple and ExecScan() is
* responsible for checking the tuple returned against the qual-clause.
*
* A 'recheck method' must also be provided that can check an
* arbitrary tuple of the relation against any qual conditions
* that are implemented internal to the access method.
*
* Conditions:
* -- the "cursor" maintained by the AMI is positioned at the tuple
* returned previously.
*
* Initial States:
* -- the relation indicated is opened for scanning so that the
* "cursor" is positioned before the first qualifying tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecScan(ScanState *node,
ExecScanAccessMtd accessMtd, /* function returning a tuple */
ExecScanRecheckMtd recheckMtd)
{
ExprContext *econtext;
List *qual;
ProjectionInfo *projInfo;
/*
* Fetch data from node
*/
qual = node->ps.qual;
projInfo = node->ps.ps_ProjInfo;
econtext = node->ps.ps_ExprContext;
/*
* If we have neither a qual to check nor a projection to do, just skip
* all the overhead and return the raw scan tuple.
*/
if (!qual && !projInfo)
{
ResetExprContext(econtext);
return ExecScanFetch(node, accessMtd, recheckMtd);
}
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle.
*/
ResetExprContext(econtext);
/*
* get a tuple from the access method. Loop until we obtain a tuple that
* passes the qualification.
*/
for (;;)
{
TupleTableSlot *slot;
CHECK_FOR_INTERRUPTS();
slot = ExecScanFetch(node, accessMtd, recheckMtd);
/*
* if the slot returned by the accessMtd contains NULL, then it means
* there is nothing more to scan so we just return an empty slot,
* being careful to use the projection result slot so it has correct
* tupleDesc.
*/
if (TupIsNull(slot))
{
if (projInfo)
return ExecClearTuple(projInfo->pi_slot);
else
return slot;
}
/*
* place the current tuple into the expr context
*/
econtext->ecxt_scantuple = slot;
/*
* check that the current tuple satisfies the qual-clause
*
* check for non-nil qual here to avoid a function call to ExecQual()
* when the qual is nil ... saves only a few cycles, but they add up
* ...
*/
if (!qual || ExecQual(qual, econtext, false))
{
/*
* Found a satisfactory scan tuple.
*/
if (projInfo)
{
/*
* Form a projection tuple, store it in the result tuple slot
* and return it.
*/
return ExecProject(projInfo);
}
else
{
/*
* Here, we aren't projecting, so just return scan tuple.
*/
return slot;
}
}
else
InstrCountFiltered1(node, 1);
/*
* Tuple fails qual, so free per-tuple memory and try again.
*/
ResetExprContext(econtext);
}
}
/* ----------------------------------------------------------------
* BitmapHeapNext
*
* Retrieve next tuple from the BitmapHeapScan node's currentRelation
* ----------------------------------------------------------------
*/
static TupleTableSlot *
BitmapHeapNext(BitmapHeapScanState *node)
{
EState *estate;
ExprContext *econtext;
HeapScanDesc scandesc;
Index scanrelid;
TIDBitmap *tbm;
TBMIterateResult *tbmres;
OffsetNumber targoffset;
TupleTableSlot *slot;
OnDiskBitmapWords *odbm;
ODBMIterateResult *odbmres;
bool inmem = false;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
scandesc = node->ss.ss_currentScanDesc;
scanrelid = ((BitmapHeapScan *) node->ss.ps.plan)->scan.scanrelid;
tbm = node->tbm;
tbmres = node->tbmres;
odbm = node->odbm;
odbmres = node->odbmres;
/*
* Clear any reference to the previously returned tuple. The idea here is
* to not have the tuple slot be the last holder of a pin on that tuple's
* buffer; if it is, we'll need a separate visit to the bufmgr to release
* the buffer. By clearing here, we get to have the release done by
* ReleaseAndReadBuffer, below.
*/
ExecClearTuple(slot);
/*
* Check if we are evaluating PlanQual for tuple of this relation.
* Additional checking is not good, but no other way for now. We could
* introduce new nodes for this case and handle IndexScan --> NewNode
* switching in Init/ReScan plan...
*/
if (estate->es_evTuple != NULL &&
estate->es_evTuple[scanrelid - 1] != NULL)
{
if (estate->es_evTupleNull[scanrelid - 1])
return slot; /* return empty slot */
ExecStoreTuple(estate->es_evTuple[scanrelid - 1],
slot, InvalidBuffer, false);
/* Does the tuple meet the original qual conditions? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext, false))
ExecClearTuple(slot); /* would not be returned by scan */
/* Flag for the next call that no more tuples */
estate->es_evTupleNull[scanrelid - 1] = true;
return slot;
}
/* check if this requires in-mem bitmap scan or on-disk bitmap index. */
inmem = ((BitmapHeapScan*)(((PlanState*)node)->plan))->inmem;
/*
* If the underline indexes are on disk bitmap indexes
*/
if (!inmem) {
uint64 nextTid = 0;
if (odbm == NULL)
{
odbm = odbm_create(ODBM_MAX_WORDS);
node->odbm = odbm;
}
if (odbmres == NULL)
{
odbmres = odbm_res_create(odbm);
node->odbmres = odbmres;
}
for (;;)
{
/* If we have used up the words from previous scan, or
we haven't scan the underlying index scan for wrods yet,
then do it.
*/
if (odbm->numOfWords == 0 &&
odbmres->nextTidLoc >= odbmres->numOfTids)
{
Plan* outerPlan = (((PlanState*)node)->lefttree)->plan;
odbm_set_bitmaptype(outerPlan, false);
odbm->firstTid = odbmres->nextTid;
odbm->startNo = 0;
odbm_set_child_resultnode(((PlanState*)node)->lefttree,
odbm);
odbm = (OnDiskBitmapWords *)
MultiExecProcNode(outerPlanState(node));
if (!odbm || !IsA(odbm, OnDiskBitmapWords))
elog(ERROR, "unrecognized result from subplan");
odbm_begin_iterate(node->odbm, node->odbmres);
}
/* If we can not find more words, then this scan is over. */
if (odbm == NULL ||
(odbm->numOfWords == 0 &&
odbmres->nextTidLoc >= odbmres->numOfTids))
return ExecClearTuple(slot);
nextTid = odbm_findnexttid(odbm, odbmres);
if (nextTid == 0)
continue;
ItemPointerSet(&scandesc->rs_ctup.t_self,
(nextTid-1)/MaxNumHeapTuples,
((nextTid-1)%MaxNumHeapTuples)+1);
/* fetch the heap tuple and see if it matches the snapshot. */
if (heap_release_fetch(scandesc->rs_rd,
scandesc->rs_snapshot,
&scandesc->rs_ctup,
&scandesc->rs_cbuf,
true,
&scandesc->rs_pgstat_info))
{
/*
* Set up the result slot to point to this tuple.
* Note that the slot acquires a pin on the buffer.
*/
ExecStoreTuple(&scandesc->rs_ctup,
slot,
scandesc->rs_cbuf,
false);
/* return this tuple */
return slot;
}
}
}
/*
* If we haven't yet performed the underlying index scan, do it, and
* prepare the bitmap to be iterated over.
*/
if (tbm == NULL)
{
tbm = (TIDBitmap *) MultiExecProcNode(outerPlanState(node));
if (!tbm || !IsA(tbm, TIDBitmap))
elog(ERROR, "unrecognized result from subplan");
node->tbm = tbm;
node->tbmres = tbmres = NULL;
tbm_begin_iterate(tbm);
}
for (;;)
{
/*
* Get next page of results if needed
*/
if (tbmres == NULL)
{
node->tbmres = tbmres = tbm_iterate(tbm);
if (tbmres == NULL)
{
/* no more entries in the bitmap */
break;
}
/*
* Ignore any claimed entries past what we think is the end of the
* relation. (This is probably not necessary given that we got
* AccessShareLock before performing any of the indexscans, but
* let's be safe.)
*/
if (tbmres->blockno >= scandesc->rs_nblocks)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* Acquire pin on the current heap page. We'll hold the pin until
* done looking at the page. We trade in any pin we held before.
*/
scandesc->rs_cbuf = ReleaseAndReadBuffer(scandesc->rs_cbuf,
scandesc->rs_rd,
tbmres->blockno);
/*
* Determine how many entries we need to look at on this page. If
* the bitmap is lossy then we need to look at each physical item
* pointer; otherwise we just look through the offsets listed in
* tbmres.
*/
if (tbmres->ntuples >= 0)
{
/* non-lossy case */
node->minslot = 0;
node->maxslot = tbmres->ntuples - 1;
}
else
{
/* lossy case */
Page dp;
LockBuffer(scandesc->rs_cbuf, BUFFER_LOCK_SHARE);
dp = (Page) BufferGetPage(scandesc->rs_cbuf);
node->minslot = FirstOffsetNumber;
node->maxslot = PageGetMaxOffsetNumber(dp);
LockBuffer(scandesc->rs_cbuf, BUFFER_LOCK_UNLOCK);
}
/*
* Set curslot to first slot to examine
*/
node->curslot = node->minslot;
}
else
{
/*
* Continuing in previously obtained page; advance curslot
*/
node->curslot++;
}
/*
* Out of range? If so, nothing more to look at on this page
*/
if (node->curslot < node->minslot || node->curslot > node->maxslot)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* Okay to try to fetch the tuple
*/
if (tbmres->ntuples >= 0)
{
/* non-lossy case */
targoffset = tbmres->offsets[node->curslot];
}
else
{
/* lossy case */
targoffset = (OffsetNumber) node->curslot;
}
ItemPointerSet(&scandesc->rs_ctup.t_self, tbmres->blockno, targoffset);
/*
* Fetch the heap tuple and see if it matches the snapshot. We use
* heap_release_fetch to avoid useless bufmgr traffic.
*/
if (heap_release_fetch(scandesc->rs_rd,
scandesc->rs_snapshot,
&scandesc->rs_ctup,
&scandesc->rs_cbuf,
true,
&scandesc->rs_pgstat_info))
{
/*
* Set up the result slot to point to this tuple. Note that the
* slot acquires a pin on the buffer.
*/
ExecStoreTuple(&scandesc->rs_ctup,
slot,
scandesc->rs_cbuf,
false);
/*
* If we are using lossy info, we have to recheck the qual
* conditions at every tuple.
*/
if (tbmres->ntuples < 0)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext, false))
{
/* Fails recheck, so drop it and loop back for another */
ExecClearTuple(slot);
continue;
}
}
/* OK to return this tuple */
return slot;
}
/*
* Failed the snap, so loop back and try again.
*/
}
/*
* if we get here it means we are at the end of the scan..
*/
return ExecClearTuple(slot);
}
/*
* IndexSpoolInsert -
*
* Copy from ExecInsertIndexTuples.
*/
static void
IndexSpoolInsert(BTSpool **spools, TupleTableSlot *slot, ItemPointer tupleid, EState *estate, bool reindex)
{
ResultRelInfo *relinfo;
int i;
int numIndices;
RelationPtr indices;
IndexInfo **indexInfoArray;
Relation heapRelation;
ExprContext *econtext;
/*
* Get information from the result relation relinfo structure.
*/
relinfo = estate->es_result_relation_info;
numIndices = relinfo->ri_NumIndices;
indices = relinfo->ri_IndexRelationDescs;
indexInfoArray = relinfo->ri_IndexRelationInfo;
heapRelation = relinfo->ri_RelationDesc;
/*
* We will use the EState's per-tuple context for evaluating predicates
* and index expressions (creating it if it's not already there).
*/
econtext = GetPerTupleExprContext(estate);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
for (i = 0; i < numIndices; i++)
{
Datum values[INDEX_MAX_KEYS];
bool isnull[INDEX_MAX_KEYS];
IndexInfo *indexInfo;
if (indices[i] == NULL)
continue;
/* Skip non-btree indexes on reindex mode. */
if (reindex && spools != NULL && spools[i] == NULL)
continue;
indexInfo = indexInfoArray[i];
/* If the index is marked as read-only, ignore it */
if (!indexInfo->ii_ReadyForInserts)
continue;
/* Check for partial index */
if (indexInfo->ii_Predicate != NIL)
{
List *predicate;
/*
* If predicate state not set up yet, create it (in the estate's
* per-query context)
*/
predicate = indexInfo->ii_PredicateState;
if (predicate == NIL)
{
predicate = (List *) ExecPrepareExpr((Expr *) indexInfo->ii_Predicate, estate);
indexInfo->ii_PredicateState = predicate;
}
/* Skip this index-update if the predicate isn'loader satisfied */
if (!ExecQual(predicate, econtext, false))
continue;
}
FormIndexDatum(indexInfo, slot, estate, values, isnull);
/*
* Insert or spool the tuple.
*/
if (spools != NULL && spools[i] != NULL)
{
IndexTuple itup = index_form_tuple(RelationGetDescr(indices[i]), values, isnull);
itup->t_tid = *tupleid;
_bt_spool(itup, spools[i]);
pfree(itup);
}
else
{
/* Insert one by one */
index_insert(indices[i], values, isnull, tupleid, heapRelation, indices[i]->rd_index->indisunique);
}
}
}
/* ----------------------------------------------------------------
* IndexOnlyNext
*
* Retrieve a tuple from the IndexOnlyScan node's index.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
IndexOnlyNext(IndexOnlyScanState *node)
{
EState *estate;
ExprContext *econtext;
ScanDirection direction;
IndexScanDesc scandesc;
TupleTableSlot *slot;
ItemPointer tid;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
direction = estate->es_direction;
/* flip direction if this is an overall backward scan */
if (ScanDirectionIsBackward(((IndexOnlyScan *) node->ss.ps.plan)->indexorderdir))
{
if (ScanDirectionIsForward(direction))
direction = BackwardScanDirection;
else if (ScanDirectionIsBackward(direction))
direction = ForwardScanDirection;
}
scandesc = node->ioss_ScanDesc;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
/*
* OK, now that we have what we need, fetch the next tuple.
*/
while ((tid = index_getnext_tid(scandesc, direction)) != NULL)
{
HeapTuple tuple = NULL;
/*
* We can skip the heap fetch if the TID references a heap page on
* which all tuples are known visible to everybody. In any case,
* we'll use the index tuple not the heap tuple as the data source.
*
* Note on Memory Ordering Effects: visibilitymap_test does not lock
* the visibility map buffer, and therefore the result we read here
* could be slightly stale. However, it can't be stale enough to
* matter.
*
* We need to detect clearing a VM bit due to an insert right away,
* because the tuple is present in the index page but not visible. The
* reading of the TID by this scan (using a shared lock on the index
* buffer) is serialized with the insert of the TID into the index
* (using an exclusive lock on the index buffer). Because the VM bit
* is cleared before updating the index, and locking/unlocking of the
* index page acts as a full memory barrier, we are sure to see the
* cleared bit if we see a recently-inserted TID.
*
* Deletes do not update the index page (only VACUUM will clear out
* the TID), so the clearing of the VM bit by a delete is not
* serialized with this test below, and we may see a value that is
* significantly stale. However, we don't care about the delete right
* away, because the tuple is still visible until the deleting
* transaction commits or the statement ends (if it's our
* transaction). In either case, the lock on the VM buffer will have
* been released (acting as a write barrier) after clearing the
* bit. And for us to have a snapshot that includes the deleting
* transaction (making the tuple invisible), we must have acquired
* ProcArrayLock after that time, acting as a read barrier.
*
* It's worth going through this complexity to avoid needing to lock
* the VM buffer, which could cause significant contention.
*/
if (!visibilitymap_test(scandesc->heapRelation,
ItemPointerGetBlockNumber(tid),
&node->ioss_VMBuffer))
{
/*
* Rats, we have to visit the heap to check visibility.
*/
node->ioss_HeapFetches++;
tuple = index_fetch_heap(scandesc);
if (tuple == NULL)
continue; /* no visible tuple, try next index entry */
/*
* Only MVCC snapshots are supported here, so there should be no
* need to keep following the HOT chain once a visible entry has
* been found. If we did want to allow that, we'd need to keep
* more state to remember not to call index_getnext_tid next time.
*/
if (scandesc->xs_continue_hot)
elog(ERROR, "non-MVCC snapshots are not supported in index-only scans");
/*
* Note: at this point we are holding a pin on the heap page, as
* recorded in scandesc->xs_cbuf. We could release that pin now,
* but it's not clear whether it's a win to do so. The next index
* entry might require a visit to the same heap page.
*/
}
/*
* Fill the scan tuple slot with data from the index.
*/
StoreIndexTuple(slot, scandesc->xs_itup, scandesc->xs_itupdesc);
/*
* If the index was lossy, we have to recheck the index quals.
* (Currently, this can never happen, but we should support the case
* for possible future use, eg with GiST indexes.)
*/
if (scandesc->xs_recheck)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->indexqual, econtext, false))
{
/* Fails recheck, so drop it and loop back for another */
InstrCountFiltered2(node, 1);
continue;
}
}
/*
* We don't currently support rechecking ORDER BY distances. (In
* principle, if the index can support retrieval of the originally
* indexed value, it should be able to produce an exact distance
* calculation too. So it's not clear that adding code here for
* recheck/re-sort would be worth the trouble. But we should at least
* throw an error if someone tries it.)
*/
if (scandesc->numberOfOrderBys > 0 && scandesc->xs_recheckorderby)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("lossy distance functions are not supported in index-only scans")));
/*
* Predicate locks for index-only scans must be acquired at the page
* level when the heap is not accessed, since tuple-level predicate
* locks need the tuple's xmin value. If we had to visit the tuple
* anyway, then we already have the tuple-level lock and can skip the
* page lock.
*/
if (tuple == NULL)
PredicateLockPage(scandesc->heapRelation,
ItemPointerGetBlockNumber(tid),
estate->es_snapshot);
return slot;
}
/*
* if we get here it means the index scan failed so we are at the end of
* the scan..
*/
return ExecClearTuple(slot);
}
/* ----------------------------------------------------------------
* IndexNext
*
* Retrieve a tuple from the IndexScan node's currentRelation
* using the index specified in the IndexScanState information.
* ----------------------------------------------------------------
*/
TupleTableSlot *
IndexNext(IndexScanState *node)
{
EState *estate;
ExprContext *econtext;
ScanDirection direction;
IndexScanDesc scandesc;
Index scanrelid;
HeapTuple tuple;
TupleTableSlot *slot;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
direction = estate->es_direction;
initScanDesc(node);
/* flip direction if this is an overall backward scan */
if (ScanDirectionIsBackward(((IndexScan *) node->ss.ps.plan)->indexorderdir))
{
if (ScanDirectionIsForward(direction))
direction = BackwardScanDirection;
else if (ScanDirectionIsBackward(direction))
direction = ForwardScanDirection;
}
scandesc = node->iss_ScanDesc;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
scanrelid = ((IndexScan *) node->ss.ps.plan)->scan.scanrelid;
/*
* Check if we are evaluating PlanQual for tuple of this relation.
* Additional checking is not good, but no other way for now. We could
* introduce new nodes for this case and handle IndexScan --> NewNode
* switching in Init/ReScan plan...
*/
if (estate->es_evTuple != NULL &&
estate->es_evTuple[scanrelid - 1] != NULL)
{
if (estate->es_evTupleNull[scanrelid - 1])
{
if (!node->ss.ps.delayEagerFree)
{
ExecEagerFreeIndexScan(node);
}
return ExecClearTuple(slot);
}
ExecStoreGenericTuple(estate->es_evTuple[scanrelid - 1], slot, false);
/* Does the tuple meet the indexqual condition? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->indexqualorig, econtext, false))
{
if (!node->ss.ps.delayEagerFree)
{
ExecEagerFreeIndexScan(node);
}
ExecClearTuple(slot); /* would not be returned by scan */
}
/* Flag for the next call that no more tuples */
estate->es_evTupleNull[scanrelid - 1] = true;
Gpmon_M_Incr_Rows_Out(GpmonPktFromIndexScanState(node));
CheckSendPlanStateGpmonPkt(&node->ss.ps);
return slot;
}
/*
* ok, now that we have what we need, fetch the next tuple.
*/
if ((tuple = index_getnext(scandesc, direction)) != NULL)
{
/*
* Store the scanned tuple in the scan tuple slot of the scan state.
* Note: we pass 'false' because tuples returned by amgetnext are
* pointers onto disk pages and must not be pfree()'d.
*/
ExecStoreHeapTuple(tuple, /* tuple to store */
slot, /* slot to store in */
scandesc->xs_cbuf, /* buffer containing tuple */
false); /* don't pfree */
Gpmon_M_Incr_Rows_Out(GpmonPktFromIndexScanState(node));
CheckSendPlanStateGpmonPkt(&node->ss.ps);
return slot;
}
if (!node->ss.ps.delayEagerFree)
{
ExecEagerFreeIndexScan(node);
}
/*
* if we get here it means the index scan failed so we are at the end of
* the scan..
*/
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);
}
}
/* ----------------------------------------------------------------
* ExecNestLoop(node)
*
* old comments
* Returns the tuple joined from inner and outer tuples which
* satisfies the qualification clause.
*
* It scans the inner relation to join with current outer tuple.
*
* If none is found, next tuple from the outer relation is retrieved
* and the inner relation is scanned from the beginning again to join
* with the outer tuple.
*
* NULL is returned if all the remaining outer tuples are tried and
* all fail to join with the inner tuples.
*
* NULL is also returned if there is no tuple from inner relation.
*
* Conditions:
* -- outerTuple contains current tuple from outer relation and
* the right son(inner relation) maintains "cursor" at the tuple
* returned previously.
* This is achieved by maintaining a scan position on the outer
* relation.
*
* Initial States:
* -- the outer child and the inner child
* are prepared to return the first tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecNestLoop(NestLoopState *node)
{
PlanState *innerPlan;
PlanState *outerPlan;
TupleTableSlot *outerTupleSlot;
TupleTableSlot *innerTupleSlot;
List *joinqual;
List *otherqual;
ExprContext *econtext;
/*
* get information from the node
*/
ENL1_printf("getting info from node");
joinqual = node->js.joinqual;
otherqual = node->js.ps.qual;
outerPlan = outerPlanState(node);
innerPlan = innerPlanState(node);
econtext = node->js.ps.ps_ExprContext;
/*
* get the current outer tuple
*/
outerTupleSlot = node->js.ps.ps_OuterTupleSlot;
econtext->ecxt_outertuple = outerTupleSlot;
/*
* Check to see if we're still projecting out tuples from a previous join
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->js.ps.ps_TupFromTlist)
{
TupleTableSlot *result;
ExprDoneCond isDone;
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone == ExprMultipleResult)
return result;
/* Done with that source tuple... */
node->js.ps.ps_TupFromTlist = false;
}
/*
* If we're doing an IN join, we want to return at most one row per outer
* tuple; so we can stop scanning the inner scan if we matched on the
* previous try.
*/
if (node->js.jointype == JOIN_IN &&
node->nl_MatchedOuter)
node->nl_NeedNewOuter = true;
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't happen
* until we're done projecting out tuples from a join tuple.
*/
ResetExprContext(econtext);
/*
* Ok, everything is setup for the join so now loop until we return a
* qualifying join tuple.
*/
ENL1_printf("entering main loop");
for (;;)
{
/*
* If we don't have an outer tuple, get the next one and reset the
* inner scan.
*/
if (node->nl_NeedNewOuter)
{
ENL1_printf("getting new outer tuple");
outerTupleSlot = ExecProcNode(outerPlan);
/*
* if there are no more outer tuples, then the join is complete..
*/
if (TupIsNull(outerTupleSlot))
{
ENL1_printf("no outer tuple, ending join");
return NULL;
}
ENL1_printf("saving new outer tuple information");
node->js.ps.ps_OuterTupleSlot = outerTupleSlot;
econtext->ecxt_outertuple = outerTupleSlot;
node->nl_NeedNewOuter = false;
node->nl_MatchedOuter = false;
/*
* now rescan the inner plan
*/
ENL1_printf("rescanning inner plan");
/*
* The scan key of the inner plan might depend on the current
* outer tuple (e.g. in index scans), that's why we pass our expr
* context.
*/
ExecReScan(innerPlan, econtext);
}
/*
* we have an outerTuple, try to get the next inner tuple.
*/
ENL1_printf("getting new inner tuple");
innerTupleSlot = ExecProcNode(innerPlan);
econtext->ecxt_innertuple = innerTupleSlot;
if (TupIsNull(innerTupleSlot))
{
ENL1_printf("no inner tuple, need new outer tuple");
node->nl_NeedNewOuter = true;
if (!node->nl_MatchedOuter &&
node->js.jointype == JOIN_LEFT)
{
/*
* We are doing an outer join and there were no join matches
* for this outer tuple. Generate a fake join tuple with
* nulls for the inner tuple, and return it if it passes the
* non-join quals.
*/
econtext->ecxt_innertuple = node->nl_NullInnerTupleSlot;
ENL1_printf("testing qualification for outer-join tuple");
if (ExecQual(otherqual, econtext, false))
{
/*
* qualification was satisfied so we project and return
* the slot containing the result tuple using
* ExecProject().
*/
TupleTableSlot *result;
ExprDoneCond isDone;
ENL1_printf("qualification succeeded, projecting tuple");
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->js.ps.ps_TupFromTlist =
(isDone == ExprMultipleResult);
return result;
}
}
}
/*
* Otherwise just return to top of loop for a new outer tuple.
*/
continue;
}
/*
* at this point we have a new pair of inner and outer tuples so we
* test the inner and outer tuples to see if they satisfy the node's
* qualification.
*
* Only the joinquals determine MatchedOuter status, but all quals
* must pass to actually return the tuple.
*/
ENL1_printf("testing qualification");
if (ExecQual(joinqual, econtext, false))
{
node->nl_MatchedOuter = true;
if (otherqual == NIL || ExecQual(otherqual, econtext, false))
{
/*
* qualification was satisfied so we project and return the
* slot containing the result tuple using ExecProject().
*/
TupleTableSlot *result;
ExprDoneCond isDone;
ENL1_printf("qualification succeeded, projecting tuple");
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->js.ps.ps_TupFromTlist =
(isDone == ExprMultipleResult);
return result;
}
}
/* If we didn't return a tuple, may need to set NeedNewOuter */
if (node->js.jointype == JOIN_IN)
node->nl_NeedNewOuter = true;
}
/*
* Tuple fails qual, so free per-tuple memory and try again.
*/
ResetExprContext(econtext);
ENL1_printf("qualification failed, looping");
}
}
/* ----------------------------------------------------------------
* ExecScanHashBucket
*
* scan a hash bucket of matches
* ----------------------------------------------------------------
*/
HeapTuple
ExecScanHashBucket(HashJoinState *hjstate,
HashBucket bucket,
HeapTuple curtuple,
List *hjclauses,
ExprContext *econtext)
{
HeapTuple heapTuple;
bool qualResult;
OverflowTuple otuple = NULL;
OverflowTuple curotuple;
TupleTableSlot *inntuple;
OverflowTuple firstotuple;
OverflowTuple lastotuple;
HashJoinTable hashtable;
hashtable = hjstate->hj_HashTable;
firstotuple = (OverflowTuple)ABSADDR(bucket->firstotuple);
lastotuple = (OverflowTuple)ABSADDR(bucket->lastotuple);
/* ----------------
* search the hash bucket
* ----------------
*/
if (curtuple == NULL || curtuple < (HeapTuple)ABSADDR(bucket->bottom)) {
if (curtuple == NULL)
heapTuple = (HeapTuple)
LONGALIGN(ABSADDR(bucket->top));
else
heapTuple = (HeapTuple)
LONGALIGN(((char*)curtuple+curtuple->t_len));
while (heapTuple < (HeapTuple)ABSADDR(bucket->bottom)) {
inntuple = ExecStoreTuple(heapTuple, /* tuple to store */
hjstate->hj_HashTupleSlot, /* slot */
InvalidBuffer,/* tuple has no buffer */
false); /* do not pfree this tuple */
econtext->ecxt_innertuple = inntuple;
qualResult = ExecQual((List*)hjclauses, econtext);
if (qualResult)
return heapTuple;
heapTuple = (HeapTuple)
LONGALIGN(((char*)heapTuple+heapTuple->t_len));
}
if (firstotuple == NULL)
return NULL;
otuple = firstotuple;
}
/* ----------------
* search the overflow area of the hash bucket
* ----------------
*/
if (otuple == NULL) {
curotuple = hjstate->hj_CurOTuple;
otuple = (OverflowTuple)ABSADDR(curotuple->next);
}
while (otuple != NULL) {
heapTuple = (HeapTuple)ABSADDR(otuple->tuple);
inntuple = ExecStoreTuple(heapTuple, /* tuple to store */
hjstate->hj_HashTupleSlot, /* slot */
InvalidBuffer, /* SP?? this tuple has no buffer */
false); /* do not pfree this tuple */
econtext->ecxt_innertuple = inntuple;
qualResult = ExecQual((List*)hjclauses, econtext);
if (qualResult) {
hjstate->hj_CurOTuple = otuple;
return heapTuple;
}
otuple = (OverflowTuple)ABSADDR(otuple->next);
}
/* ----------------
* no match
* ----------------
*/
return NULL;
}
/* ----------------------------------------------------------------
* BitmapHeapNext
*
* Retrieve next tuple from the BitmapHeapScan node's currentRelation
* ----------------------------------------------------------------
*/
static TupleTableSlot *
BitmapHeapNext(BitmapHeapScanState *node)
{
ExprContext *econtext;
HeapScanDesc scan;
TIDBitmap *tbm;
TBMIterator *tbmiterator = NULL;
TBMSharedIterator *shared_tbmiterator = NULL;
TBMIterateResult *tbmres;
OffsetNumber targoffset;
TupleTableSlot *slot;
ParallelBitmapHeapState *pstate = node->pstate;
dsa_area *dsa = node->ss.ps.state->es_query_dsa;
/*
* extract necessary information from index scan node
*/
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
scan = node->ss.ss_currentScanDesc;
tbm = node->tbm;
if (pstate == NULL)
tbmiterator = node->tbmiterator;
else
shared_tbmiterator = node->shared_tbmiterator;
tbmres = node->tbmres;
/*
* If we haven't yet performed the underlying index scan, do it, and begin
* the iteration over the bitmap.
*
* For prefetching, we use *two* iterators, one for the pages we are
* actually scanning and another that runs ahead of the first for
* prefetching. node->prefetch_pages tracks exactly how many pages ahead
* the prefetch iterator is. Also, node->prefetch_target tracks the
* desired prefetch distance, which starts small and increases up to the
* node->prefetch_maximum. This is to avoid doing a lot of prefetching in
* a scan that stops after a few tuples because of a LIMIT.
*/
if (!node->initialized)
{
if (!pstate)
{
tbm = (TIDBitmap *) MultiExecProcNode(outerPlanState(node));
if (!tbm || !IsA(tbm, TIDBitmap))
elog(ERROR, "unrecognized result from subplan");
node->tbm = tbm;
node->tbmiterator = tbmiterator = tbm_begin_iterate(tbm);
node->tbmres = tbmres = NULL;
#ifdef USE_PREFETCH
if (node->prefetch_maximum > 0)
{
node->prefetch_iterator = tbm_begin_iterate(tbm);
node->prefetch_pages = 0;
node->prefetch_target = -1;
}
#endif /* USE_PREFETCH */
}
else
{
/*
* The leader will immediately come out of the function, but
* others will be blocked until leader populates the TBM and wakes
* them up.
*/
if (BitmapShouldInitializeSharedState(pstate))
{
tbm = (TIDBitmap *) MultiExecProcNode(outerPlanState(node));
if (!tbm || !IsA(tbm, TIDBitmap))
elog(ERROR, "unrecognized result from subplan");
node->tbm = tbm;
/*
* Prepare to iterate over the TBM. This will return the
* dsa_pointer of the iterator state which will be used by
* multiple processes to iterate jointly.
*/
pstate->tbmiterator = tbm_prepare_shared_iterate(tbm);
#ifdef USE_PREFETCH
if (node->prefetch_maximum > 0)
{
pstate->prefetch_iterator =
tbm_prepare_shared_iterate(tbm);
/*
* We don't need the mutex here as we haven't yet woke up
* others.
*/
pstate->prefetch_pages = 0;
pstate->prefetch_target = -1;
}
#endif
/* We have initialized the shared state so wake up others. */
BitmapDoneInitializingSharedState(pstate);
}
/* Allocate a private iterator and attach the shared state to it */
node->shared_tbmiterator = shared_tbmiterator =
tbm_attach_shared_iterate(dsa, pstate->tbmiterator);
node->tbmres = tbmres = NULL;
#ifdef USE_PREFETCH
if (node->prefetch_maximum > 0)
{
node->shared_prefetch_iterator =
tbm_attach_shared_iterate(dsa, pstate->prefetch_iterator);
}
#endif /* USE_PREFETCH */
}
node->initialized = true;
}
for (;;)
{
Page dp;
ItemId lp;
CHECK_FOR_INTERRUPTS();
/*
* Get next page of results if needed
*/
if (tbmres == NULL)
{
if (!pstate)
node->tbmres = tbmres = tbm_iterate(tbmiterator);
else
node->tbmres = tbmres = tbm_shared_iterate(shared_tbmiterator);
if (tbmres == NULL)
{
/* no more entries in the bitmap */
break;
}
BitmapAdjustPrefetchIterator(node, tbmres);
/*
* Ignore any claimed entries past what we think is the end of the
* relation. (This is probably not necessary given that we got at
* least AccessShareLock on the table before performing any of the
* indexscans, but let's be safe.)
*/
if (tbmres->blockno >= scan->rs_nblocks)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* Fetch the current heap page and identify candidate tuples.
*/
bitgetpage(scan, tbmres);
if (tbmres->ntuples >= 0)
node->exact_pages++;
else
node->lossy_pages++;
/*
* Set rs_cindex to first slot to examine
*/
scan->rs_cindex = 0;
/* Adjust the prefetch target */
BitmapAdjustPrefetchTarget(node);
}
else
{
/*
* Continuing in previously obtained page; advance rs_cindex
*/
scan->rs_cindex++;
#ifdef USE_PREFETCH
/*
* Try to prefetch at least a few pages even before we get to the
* second page if we don't stop reading after the first tuple.
*/
if (!pstate)
{
if (node->prefetch_target < node->prefetch_maximum)
node->prefetch_target++;
}
else if (pstate->prefetch_target < node->prefetch_maximum)
{
/* take spinlock while updating shared state */
SpinLockAcquire(&pstate->mutex);
if (pstate->prefetch_target < node->prefetch_maximum)
pstate->prefetch_target++;
SpinLockRelease(&pstate->mutex);
}
#endif /* USE_PREFETCH */
}
/*
* Out of range? If so, nothing more to look at on this page
*/
if (scan->rs_cindex < 0 || scan->rs_cindex >= scan->rs_ntuples)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* We issue prefetch requests *after* fetching the current page to try
* to avoid having prefetching interfere with the main I/O. Also, this
* should happen only when we have determined there is still something
* to do on the current page, else we may uselessly prefetch the same
* page we are just about to request for real.
*/
BitmapPrefetch(node, scan);
/*
* Okay to fetch the tuple
*/
targoffset = scan->rs_vistuples[scan->rs_cindex];
dp = (Page) BufferGetPage(scan->rs_cbuf);
lp = PageGetItemId(dp, targoffset);
Assert(ItemIdIsNormal(lp));
scan->rs_ctup.t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
scan->rs_ctup.t_len = ItemIdGetLength(lp);
scan->rs_ctup.t_tableOid = scan->rs_rd->rd_id;
ItemPointerSet(&scan->rs_ctup.t_self, tbmres->blockno, targoffset);
pgstat_count_heap_fetch(scan->rs_rd);
/*
* Set up the result slot to point to this tuple. Note that the slot
* acquires a pin on the buffer.
*/
ExecStoreTuple(&scan->rs_ctup,
slot,
scan->rs_cbuf,
false);
/*
* If we are using lossy info, we have to recheck the qual conditions
* at every tuple.
*/
if (tbmres->recheck)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext))
{
/* Fails recheck, so drop it and loop back for another */
InstrCountFiltered2(node, 1);
ExecClearTuple(slot);
continue;
}
}
/* OK to return this tuple */
return slot;
}
/*
* if we get here it means we are at the end of the scan..
*/
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;
/*
* 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;
}
/* ----------------------------------------------------------------
* IndexOnlyNext
*
* Retrieve a tuple from the IndexOnlyScan node's index.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
IndexOnlyNext(IndexOnlyScanState *node)
{
EState *estate;
ExprContext *econtext;
ScanDirection direction;
IndexScanDesc scandesc;
TupleTableSlot *slot;
ItemPointer tid;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
direction = estate->es_direction;
/* flip direction if this is an overall backward scan */
if (ScanDirectionIsBackward(((IndexOnlyScan *) node->ss.ps.plan)->indexorderdir))
{
if (ScanDirectionIsForward(direction))
direction = BackwardScanDirection;
else if (ScanDirectionIsBackward(direction))
direction = ForwardScanDirection;
}
scandesc = node->ioss_ScanDesc;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
/*
* OK, now that we have what we need, fetch the next tuple.
*/
while ((tid = index_getnext_tid(scandesc, direction)) != NULL)
{
HeapTuple tuple = NULL;
/*
* We can skip the heap fetch if the TID references a heap page on
* which all tuples are known visible to everybody. In any case,
* we'll use the index tuple not the heap tuple as the data source.
*
* Note on Memory Ordering Effects: visibilitymap_test does not lock
* the visibility map buffer, and therefore the result we read here
* could be slightly stale. However, it can't be stale enough to
* matter. It suffices to show that (1) there is a read barrier
* between the time we read the index TID and the time we test the
* visibility map; and (2) there is a write barrier between the time
* some other concurrent process clears the visibility map bit and the
* time it inserts the index TID. Since acquiring or releasing a
* LWLock interposes a full barrier, this is easy to show: (1) is
* satisfied by the release of the index buffer content lock after
* reading the TID; and (2) is satisfied by the acquisition of the
* buffer content lock in order to insert the TID.
*/
if (!visibilitymap_test(scandesc->heapRelation,
ItemPointerGetBlockNumber(tid),
&node->ioss_VMBuffer))
{
/*
* Rats, we have to visit the heap to check visibility.
*/
node->ioss_HeapFetches++;
tuple = index_fetch_heap(scandesc);
if (tuple == NULL)
continue; /* no visible tuple, try next index entry */
/*
* Only MVCC snapshots are supported here, so there should be no
* need to keep following the HOT chain once a visible entry has
* been found. If we did want to allow that, we'd need to keep
* more state to remember not to call index_getnext_tid next time.
*/
if (scandesc->xs_continue_hot)
elog(ERROR, "non-MVCC snapshots are not supported in index-only scans");
/*
* Note: at this point we are holding a pin on the heap page, as
* recorded in scandesc->xs_cbuf. We could release that pin now,
* but it's not clear whether it's a win to do so. The next index
* entry might require a visit to the same heap page.
*/
}
/*
* Fill the scan tuple slot with data from the index.
*/
StoreIndexTuple(slot, scandesc->xs_itup, scandesc->xs_itupdesc);
/*
* If the index was lossy, we have to recheck the index quals.
* (Currently, this can never happen, but we should support the case
* for possible future use, eg with GiST indexes.)
*/
if (scandesc->xs_recheck)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->indexqual, econtext, false))
{
/* Fails recheck, so drop it and loop back for another */
InstrCountFiltered2(node, 1);
continue;
}
}
/*
* Predicate locks for index-only scans must be acquired at the page
* level when the heap is not accessed, since tuple-level predicate
* locks need the tuple's xmin value. If we had to visit the tuple
* anyway, then we already have the tuple-level lock and can skip the
* page lock.
*/
if (tuple == NULL)
PredicateLockPage(scandesc->heapRelation,
ItemPointerGetBlockNumber(tid),
estate->es_snapshot);
return slot;
}
/*
* if we get here it means the index scan failed so we are at the end of
* the scan..
*/
return ExecClearTuple(slot);
}
/*
* ExecIndexRecommend
*
* This function obtains data directly from the RecView, which we
* assume is populated with predictions for this user.
*/
static TupleTableSlot*
ExecIndexRecommend(RecScanState *recnode,
ExecScanAccessMtd accessMtd,
ExecScanRecheckMtd recheckMtd)
{
ExprContext *econtext;
List *qual;
ProjectionInfo *projInfo;
ExprDoneCond isDone;
TupleTableSlot *resultSlot;
ScanState *node;
AttributeInfo *attributes;
node = recnode->subscan;
attributes = (AttributeInfo*) recnode->attributes;
/*
* Fetch data from node
*/
qual = node->ps.qual;
projInfo = node->ps.ps_ProjInfo;
econtext = node->ps.ps_ExprContext;
/*
* Check to see if we're still projecting out tuples from a previous scan
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->ps.ps_TupFromTlist)
{
Assert(projInfo); /* can't get here if not projecting */
resultSlot = ExecProject(projInfo, &isDone);
if (isDone == ExprMultipleResult)
return resultSlot;
/* Done with that source tuple... */
node->ps.ps_TupFromTlist = false;
}
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't happen
* until we're done projecting out tuples from a scan tuple.
*/
ResetExprContext(econtext);
/*
* get a tuple from the access method. Loop until we obtain a tuple that
* passes the qualification.
*/
for (;;)
{
TupleTableSlot *slot;
int userID;
bool recQual = true;
CHECK_FOR_INTERRUPTS();
slot = recnode->ss.ps.ps_ResultTupleSlot;
/* If we're using the RecView, we're going to fetch a new
* tuple every time. */
slot = ExecRecFetch(node, accessMtd, recheckMtd);
/* If the slot is null now, then we've run out of tuples
* to return, so we're done. */
if (TupIsNull(slot))
{
if (projInfo)
return ExecClearTuple(projInfo->pi_slot);
else
return slot;
}
/*
* Before we check the qualifications, we're going to manually check
* to see that the tuple matches the provided user ID, because this
* is always necessary and it's easier than messing with the target
* list.
*/
/* First, we'll make sure we're dealing with the right user. */
userID = getTupleInt(slot,attributes->userkey);
/* How we could fail to find the user ID, I don't know. */
if (userID < 0)
elog(ERROR, "user ID column not found");
/* If this tuple doesn't match the user ID, just skip it
* and move on. */
if (userID != attributes->userID)
recQual = false;
/*
* place the current tuple into the expr context
*/
econtext->ecxt_scantuple = slot;
/*
* check that the current tuple satisfies the qual-clause
*
* check for non-nil qual here to avoid a function call to ExecQual()
* when the qual is nil ... saves only a few cycles, but they add up
* ...
*
* we also make sure that the tuple passes our recommender qual
*/
if (recQual && (!qual || ExecQual(qual, econtext, false)))
{
/*
* Found a satisfactory scan tuple.
*/
if (projInfo)
{
/*
* Form a projection tuple, store it in the result tuple slot
* and return it --- unless we find we can project no tuples
* from this scan tuple, in which case continue scan.
*/
resultSlot = ExecProject(projInfo, &isDone);
if (isDone != ExprEndResult)
{
node->ps.ps_TupFromTlist = (isDone == ExprMultipleResult);
return resultSlot;
}
}
else
{
/*
* Here, we aren't projecting, so just return scan tuple.
*/
return slot;
}
}
else
InstrCountFiltered1(node, 1);
/*
* Tuple fails qual, so free per-tuple memory and try again.
*/
ResetExprContext(econtext);
}
}
/* ----------------------------------------------------------------
* BitmapHeapNext
*
* Retrieve next tuple from the BitmapHeapScan node's currentRelation
* ----------------------------------------------------------------
*/
static TupleTableSlot *
BitmapHeapNext(BitmapHeapScanState *node)
{
ExprContext *econtext;
HeapScanDesc scan;
TIDBitmap *tbm;
TBMIterator *tbmiterator;
TBMIterateResult *tbmres;
TBMIterator *prefetch_iterator;
OffsetNumber targoffset;
TupleTableSlot *slot;
/*
* extract necessary information from index scan node
*/
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
scan = node->ss.ss_currentScanDesc;
tbm = node->tbm;
tbmiterator = node->tbmiterator;
tbmres = node->tbmres;
prefetch_iterator = node->prefetch_iterator;
/*
* If we haven't yet performed the underlying index scan, do it, and begin
* the iteration over the bitmap.
*
* For prefetching, we use *two* iterators, one for the pages we are
* actually scanning and another that runs ahead of the first for
* prefetching. node->prefetch_pages tracks exactly how many pages ahead
* the prefetch iterator is. Also, node->prefetch_target tracks the
* desired prefetch distance, which starts small and increases up to the
* GUC-controlled maximum, target_prefetch_pages. This is to avoid doing
* a lot of prefetching in a scan that stops after a few tuples because of
* a LIMIT.
*/
if (tbm == NULL)
{
tbm = (TIDBitmap *) MultiExecProcNode(outerPlanState(node));
if (!tbm || !IsA(tbm, TIDBitmap))
elog(ERROR, "unrecognized result from subplan");
node->tbm = tbm;
node->tbmiterator = tbmiterator = tbm_begin_iterate(tbm);
node->tbmres = tbmres = NULL;
#ifdef USE_PREFETCH
if (target_prefetch_pages > 0)
{
node->prefetch_iterator = prefetch_iterator = tbm_begin_iterate(tbm);
node->prefetch_pages = 0;
node->prefetch_target = -1;
}
#endif /* USE_PREFETCH */
}
for (;;)
{
Page dp;
ItemId lp;
/*
* Get next page of results if needed
*/
if (tbmres == NULL)
{
node->tbmres = tbmres = tbm_iterate(tbmiterator);
if (tbmres == NULL)
{
/* no more entries in the bitmap */
break;
}
#ifdef USE_PREFETCH
if (node->prefetch_pages > 0)
{
/* The main iterator has closed the distance by one page */
node->prefetch_pages--;
}
else if (prefetch_iterator)
{
/* Do not let the prefetch iterator get behind the main one */
TBMIterateResult *tbmpre = tbm_iterate(prefetch_iterator);
if (tbmpre == NULL || tbmpre->blockno != tbmres->blockno)
elog(ERROR, "prefetch and main iterators are out of sync");
}
#endif /* USE_PREFETCH */
/*
* Ignore any claimed entries past what we think is the end of the
* relation. (This is probably not necessary given that we got at
* least AccessShareLock on the table before performing any of the
* indexscans, but let's be safe.)
*/
if (tbmres->blockno >= scan->rs_nblocks)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* Fetch the current heap page and identify candidate tuples.
*/
bitgetpage(scan, tbmres);
/*
* Set rs_cindex to first slot to examine
*/
scan->rs_cindex = 0;
#ifdef USE_PREFETCH
/*
* Increase prefetch target if it's not yet at the max. Note that
* we will increase it to zero after fetching the very first
* page/tuple, then to one after the second tuple is fetched, then
* it doubles as later pages are fetched.
*/
if (node->prefetch_target >= target_prefetch_pages)
/* don't increase any further */ ;
else if (node->prefetch_target >= target_prefetch_pages / 2)
node->prefetch_target = target_prefetch_pages;
else if (node->prefetch_target > 0)
node->prefetch_target *= 2;
else
node->prefetch_target++;
#endif /* USE_PREFETCH */
}
else
{
/*
* Continuing in previously obtained page; advance rs_cindex
*/
scan->rs_cindex++;
#ifdef USE_PREFETCH
/*
* Try to prefetch at least a few pages even before we get to the
* second page if we don't stop reading after the first tuple.
*/
if (node->prefetch_target < target_prefetch_pages)
node->prefetch_target++;
#endif /* USE_PREFETCH */
}
/*
* Out of range? If so, nothing more to look at on this page
*/
if (scan->rs_cindex < 0 || scan->rs_cindex >= scan->rs_ntuples)
{
node->tbmres = tbmres = NULL;
continue;
}
#ifdef USE_PREFETCH
/*
* We issue prefetch requests *after* fetching the current page to try
* to avoid having prefetching interfere with the main I/O. Also, this
* should happen only when we have determined there is still something
* to do on the current page, else we may uselessly prefetch the same
* page we are just about to request for real.
*/
if (prefetch_iterator)
{
while (node->prefetch_pages < node->prefetch_target)
{
TBMIterateResult *tbmpre = tbm_iterate(prefetch_iterator);
if (tbmpre == NULL)
{
/* No more pages to prefetch */
tbm_end_iterate(prefetch_iterator);
node->prefetch_iterator = prefetch_iterator = NULL;
break;
}
node->prefetch_pages++;
PrefetchBuffer(scan->rs_rd, MAIN_FORKNUM, tbmpre->blockno);
}
}
#endif /* USE_PREFETCH */
/*
* Okay to fetch the tuple
*/
targoffset = scan->rs_vistuples[scan->rs_cindex];
dp = (Page) BufferGetPage(scan->rs_cbuf);
lp = PageGetItemId(dp, targoffset);
Assert(ItemIdIsNormal(lp));
scan->rs_ctup.t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
scan->rs_ctup.t_len = ItemIdGetLength(lp);
ItemPointerSet(&scan->rs_ctup.t_self, tbmres->blockno, targoffset);
pgstat_count_heap_fetch(scan->rs_rd);
/*
* Set up the result slot to point to this tuple. Note that the slot
* acquires a pin on the buffer.
*/
ExecStoreTuple(&scan->rs_ctup,
slot,
scan->rs_cbuf,
false);
/*
* If we are using lossy info, we have to recheck the qual conditions
* at every tuple.
*/
if (tbmres->recheck)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext, false))
{
/* Fails recheck, so drop it and loop back for another */
ExecClearTuple(slot);
continue;
}
}
/* OK to return this tuple */
return slot;
}
/*
* if we get here it means we are at the end of the scan..
*/
return ExecClearTuple(slot);
}
/*
* ExecFilterRecommend
*
* This function just borrows a tuple descriptor from the RecView,
* but we create the data ourselves through various means.
*/
static TupleTableSlot*
ExecFilterRecommend(RecScanState *recnode,
ExecScanAccessMtd accessMtd,
ExecScanRecheckMtd recheckMtd)
{
ExprContext *econtext;
List *qual;
ProjectionInfo *projInfo;
ExprDoneCond isDone;
TupleTableSlot *resultSlot;
ScanState *node;
AttributeInfo *attributes;
node = recnode->subscan;
attributes = (AttributeInfo*) recnode->attributes;
/*
* Fetch data from node
*/
qual = node->ps.qual;
projInfo = node->ps.ps_ProjInfo;
econtext = node->ps.ps_ExprContext;
/*
* Check to see if we're still projecting out tuples from a previous scan
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->ps.ps_TupFromTlist)
{
Assert(projInfo); /* can't get here if not projecting */
resultSlot = ExecProject(projInfo, &isDone);
if (isDone == ExprMultipleResult)
return resultSlot;
/* Done with that source tuple... */
node->ps.ps_TupFromTlist = false;
}
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't happen
* until we're done projecting out tuples from a scan tuple.
*/
ResetExprContext(econtext);
/*
* get a tuple from the access method. Loop until we obtain a tuple that
* passes the qualification.
*/
for (;;)
{
TupleTableSlot *slot;
int natts, i, userID, userindex, itemID, itemindex;
CHECK_FOR_INTERRUPTS();
slot = recnode->ss.ps.ps_ResultTupleSlot;
/* The first thing we need to do is initialize our recommender
* model and other things, if we haven't done so already. */
if (!recnode->initialized)
InitializeRecommender(recnode);
/*
* If we've exhausted our item list, then we're totally
* finished. We set a flag for this. It's possible that
* we'll be in the inner loop of a join, through poor
* planning, so we'll reset the appropriate data in case
* we have to do this again, though our JoinRecommend
* should assure this doesn't happen.
*/
if (recnode->finished) {
recnode->finished = false;
recnode->userNum = 0;
recnode->itemNum = 0;
return NULL;
}
/* We're only going to fetch one tuple and store its tuple
* descriptor. We can use this tuple descriptor to make as
* many new tuples as we want. */
if (recnode->base_slot == NULL) {
slot = ExecRecFetch(node, accessMtd, recheckMtd);
recnode->base_slot = CreateTupleDescCopy(slot->tts_tupleDescriptor);
}
/* Create a new slot to operate on. */
slot = MakeSingleTupleTableSlot(recnode->base_slot);
slot->tts_isempty = false;
/*
* place the current tuple into the expr context
*/
econtext->ecxt_scantuple = slot;
/* Mark all slots as usable. */
natts = slot->tts_tupleDescriptor->natts;
for (i = 0; i < natts; i++) {
/* Mark slot. */
slot->tts_values[i] = Int32GetDatum(0);
slot->tts_isnull[i] = false;
slot->tts_nvalid++;
}
/* While we're here, record what tuple attributes
* correspond to our key columns. This will save
* us unnecessary strcmp functions. */
if (recnode->useratt < 0) {
for (i = 0; i < natts; i++) {
char* col_name = slot->tts_tupleDescriptor->attrs[i]->attname.data;
//printf("%s\n",col_name);
if (strcmp(col_name,attributes->userkey) == 0)
recnode->useratt = i;
else if (strcmp(col_name,attributes->itemkey) == 0)
recnode->itematt = i;
else if (strcmp(col_name,attributes->eventval) == 0)
recnode->eventatt = i;
}
}
/*
* We now have a problem: we need to create prediction structures
* for a user before we do filtering, so that we can have a proper
* item list. But we also need to filter before creating those
* structures, so we don't end up taking forever with it. The
* solution is to filter twice.
*/
userID = -1; itemID = -1;
/* First, replace the user ID. */
userindex = recnode->userNum;
userID = recnode->userList[userindex];
/*
* We now have a blank tuple slot that we need to fill with data.
* We have a working user ID, but not a valid item list. We'd like to
* use the filter to determine if this is a good user, but we can't
* do that without an item, in many cases. The solution is to add in
* dummy items, then compare it against the filter. If a given user ID
* doesn't make it past the filter with any item ID, then that user is
* being filtered out, and we'll move on to the next.
*/
if (recnode->newUser) {
recnode->fullItemNum = 0;
itemindex = recnode->fullItemNum;
itemID = recnode->fullItemList[itemindex];
slot->tts_values[recnode->useratt] = Int32GetDatum(userID);
slot->tts_values[recnode->itematt] = Int32GetDatum(itemID);
slot->tts_values[recnode->eventatt] = Int32GetDatum(-1);
/* We have a preliminary slot - let's test it. */
while (qual && !ExecQual(qual, econtext, false)) {
/* We failed the test. Try the next item. */
recnode->fullItemNum++;
if (recnode->fullItemNum >= recnode->fullTotalItems) {
/* If we've reached the last item, move onto the next user.
* If we've reached the last user, we're done. */
InstrCountFiltered1(node, recnode->fullTotalItems);
recnode->userNum++;
recnode->newUser = true;
recnode->fullItemNum = 0;
if (recnode->userNum >= recnode->totalUsers) {
recnode->userNum = 0;
recnode->itemNum = 0;
return NULL;
}
userindex = recnode->userNum;
userID = recnode->userList[userindex];
}
itemindex = recnode->fullItemNum;
itemID = recnode->fullItemList[itemindex];
slot->tts_values[recnode->useratt] = Int32GetDatum(userID);
slot->tts_values[recnode->itematt] = Int32GetDatum(itemID);
}
/* If we get here, then we found a user who will be actually
* returned in the results. One quick reset here. */
recnode->fullItemNum = 0;
}
/* Mark the user ID and index. */
attributes->userID = userID;
recnode->userindex = userindex;
/* With the user ID determined, we need to investigate and see
* if this is a new user. If so, attempt to create prediction
* data structures, or report that this user is invalid. We have
* to do this here, so we can establish the item list. */
if (recnode->newUser) {
recnode->validUser = prepUserForRating(recnode,userID);
recnode->newUser = false;
}
/* Now replace the item ID, if the user is valid. Otherwise,
* leave the item ID as is, as it doesn't matter what it is. */
if (recnode->validUser)
itemID = recnode->itemList[recnode->itemNum];
while (recnode->fullItemList[recnode->fullItemNum] < itemID)
recnode->fullItemNum++;
itemindex = recnode->fullItemNum;
if (recnode->fullItemList[itemindex] > itemID)
elog(ERROR, "critical item mismatch in ExecRecommend");
/* Plug in the data, marking those columns full. We also need to
* mark the rating column with something temporary. */
slot->tts_values[recnode->useratt] = Int32GetDatum(userID);
slot->tts_values[recnode->itematt] = Int32GetDatum(itemID);
slot->tts_values[recnode->eventatt] = Int32GetDatum(-1);
/* It's possible our filter criteria involves the RecScore somehow.
* If that's the case, we need to calculate it before we do the
* qual filtering. Also, if we're doing a JoinRecommend, we should
* not calculate the RecScore in this node. In the current version
* of RecDB, an OP_NOFILTER shouldn't be allowed. */
if (attributes->opType == OP_NOFILTER)
applyRecScore(recnode, slot, itemID, itemindex);
/* Move onto the next item, for next time. If we're doing a RecJoin,
* though, we'll move onto the next user instead. */
recnode->itemNum++;
if (recnode->itemNum >= recnode->totalItems ||
attributes->opType == OP_JOIN ||
attributes->opType == OP_GENERATEJOIN) {
/* If we've reached the last item, move onto the next user.
* If we've reached the last user, we're done. */
recnode->userNum++;
recnode->newUser = true;
recnode->itemNum = 0;
recnode->fullItemNum = 0;
if (recnode->userNum >= recnode->totalUsers)
recnode->finished = true;
}
/*
* check that the current tuple satisfies the qual-clause
*
* check for non-nil qual here to avoid a function call to ExecQual()
* when the qual is nil ... saves only a few cycles, but they add up
* ...
*/
if (!qual || ExecQual(qual, econtext, false))
{
/*
* If this is an invalid user, then we'll skip this tuple,
* adding one to the filter count.
*/
if (!recnode->validUser) {
InstrCountFiltered1(node, 1);
ResetExprContext(econtext);
ExecDropSingleTupleTableSlot(slot);
continue;
}
/*
* Found a satisfactory scan tuple. This is usually when
* we will calculate and apply the RecScore.
*/
if (attributes->opType == OP_FILTER || attributes->opType == OP_GENERATE)
applyRecScore(recnode, slot, itemID, itemindex);
if (projInfo)
{
/*
* Form a projection tuple, store it in the result tuple slot
* and return it --- unless we find we can project no tuples
* from this scan tuple, in which case continue scan.
*/
resultSlot = ExecProject(projInfo, &isDone);
if (isDone != ExprEndResult)
{
node->ps.ps_TupFromTlist = (isDone == ExprMultipleResult);
return resultSlot;
}
}
else
{
/*
* Here, we aren't projecting, so just return scan tuple.
*/
return slot;
}
}
else
InstrCountFiltered1(node, 1);
/*
* Tuple fails qual, so free per-tuple memory and try again.
*/
ResetExprContext(econtext);
ExecDropSingleTupleTableSlot(slot);
}
}
/* ----------------------------------------------------------------
* ExecResult(node)
*
* returns the tuples from the outer plan which satisfy the
* qualification clause. Since result nodes with right
* subtrees are never planned, we ignore the right subtree
* entirely (for now).. -cim 10/7/89
*
* The qualification containing only constant clauses are
* checked first before any processing is done. It always returns
* 'nil' if the constant qualification is not satisfied.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecResult(ResultState *node)
{
TupleTableSlot *outerTupleSlot;
TupleTableSlot *resultSlot;
PlanState *outerPlan;
ExprContext *econtext;
ExprDoneCond isDone;
econtext = node->ps.ps_ExprContext;
/*
* check constant qualifications like (2 > 1), if not already done
*/
if (node->rs_checkqual)
{
bool qualResult = ExecQual((List *) node->resconstantqual,
econtext,
false);
node->rs_checkqual = false;
if (!qualResult)
{
node->rs_done = true;
return NULL;
}
}
/*
* Check to see if we're still projecting out tuples from a previous scan
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->ps.ps_TupFromTlist)
{
resultSlot = ExecProject(node->ps.ps_ProjInfo, &isDone);
if (isDone == ExprMultipleResult)
return resultSlot;
/* Done with that source tuple... */
node->ps.ps_TupFromTlist = false;
}
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't happen
* until we're done projecting out tuples from a scan tuple.
*/
ResetExprContext(econtext);
/*
* if rs_done is true then it means that we were asked to return a
* constant tuple and we already did the last time ExecResult() was
* called, OR that we failed the constant qual check. Either way, now we
* are through.
*/
while (!node->rs_done)
{
outerPlan = outerPlanState(node);
if (outerPlan != NULL)
{
/*
* retrieve tuples from the outer plan until there are no more.
*/
outerTupleSlot = ExecProcNode(outerPlan);
if (TupIsNull(outerTupleSlot))
return NULL;
/*
* prepare to compute projection expressions, which will expect to
* access the input tuples as varno OUTER.
*/
econtext->ecxt_outertuple = outerTupleSlot;
}
else
{
/*
* if we don't have an outer plan, then we are just generating the
* results from a constant target list. Do it only once.
*/
node->rs_done = true;
}
/*
* form the result tuple using ExecProject(), and return it --- unless
* the projection produces an empty set, in which case we must loop
* back to see if there are more outerPlan tuples.
*/
resultSlot = ExecProject(node->ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->ps.ps_TupFromTlist = (isDone == ExprMultipleResult);
return resultSlot;
}
}
return NULL;
}
/* ----------------------------------------------------------------
* ExecResult(node)
*
* returns the tuples from the outer plan which satisfy the
* qualification clause. Since result nodes with right
* subtrees are never planned, we ignore the right subtree
* entirely (for now).. -cim 10/7/89
*
* The qualification containing only constant clauses are
* checked first before any processing is done. It always returns
* 'nil' if the constant qualification is not satisfied.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecResult(PlanState *pstate)
{
ResultState *node = castNode(ResultState, pstate);
TupleTableSlot *outerTupleSlot;
PlanState *outerPlan;
ExprContext *econtext;
CHECK_FOR_INTERRUPTS();
econtext = node->ps.ps_ExprContext;
/*
* check constant qualifications like (2 > 1), if not already done
*/
if (node->rs_checkqual)
{
bool qualResult = ExecQual(node->resconstantqual, econtext);
node->rs_checkqual = false;
if (!qualResult)
{
node->rs_done = true;
return NULL;
}
}
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle.
*/
ResetExprContext(econtext);
/*
* if rs_done is true then it means that we were asked to return a
* constant tuple and we already did the last time ExecResult() was
* called, OR that we failed the constant qual check. Either way, now we
* are through.
*/
while (!node->rs_done)
{
outerPlan = outerPlanState(node);
if (outerPlan != NULL)
{
/*
* retrieve tuples from the outer plan until there are no more.
*/
outerTupleSlot = ExecProcNode(outerPlan);
if (TupIsNull(outerTupleSlot))
return NULL;
/*
* prepare to compute projection expressions, which will expect to
* access the input tuples as varno OUTER.
*/
econtext->ecxt_outertuple = outerTupleSlot;
}
else
{
/*
* if we don't have an outer plan, then we are just generating the
* results from a constant target list. Do it only once.
*/
node->rs_done = true;
}
/* form the result tuple using ExecProject(), and return it */
return ExecProject(node->ps.ps_ProjInfo);
}
return NULL;
}
/*
* Repeatly output each tuple received from the outer plan with some
* defined number of times. The number of times to output a tuple is
* determined by the value of a given column in the received tuple.
*
* Note that the Repeat node also have the functionality to evaluate
* the GroupingFunc.
*/
TupleTableSlot *
ExecRepeat(RepeatState *repeatstate)
{
TupleTableSlot *outerslot;
ExprContext *econtext = repeatstate->ps.ps_ExprContext;
Repeat *node = (Repeat *)repeatstate->ps.plan;
if (repeatstate->repeat_done)
return NULL;
/*
* If the previous tuple still needs to be outputted,
* output it here.
*/
if (repeatstate->slot != NULL)
{
if (repeatstate->repeat_count > 0)
{
/* Output the previous tuple */
econtext->ecxt_outertuple = repeatstate->slot;
econtext->ecxt_scantuple = repeatstate->slot;
do
{
econtext->group_id = repeatstate->repeat_count - 1;
econtext->grouping = node->grouping;
repeatstate->repeat_count--;
/* Check the qual until we find one output tuple. */
if (ExecQual(repeatstate->ps.qual, econtext, false))
{
Gpmon_M_Incr_Rows_Out(GpmonPktFromRepeatState(repeatstate));
CheckSendPlanStateGpmonPkt(&repeatstate->ps);
return ExecProject(repeatstate->ps.ps_ProjInfo, NULL);
}
} while (repeatstate->repeat_count > 0);
}
else
repeatstate->slot = NULL;
}
ResetExprContext(econtext);
while (!repeatstate->repeat_done)
{
MemoryContext oldcxt;
bool isNull = false;
outerslot = ExecProcNode(outerPlanState(repeatstate));
if (TupIsNull(outerslot))
{
repeatstate->repeat_done = true;
return NULL;
}
econtext->ecxt_outertuple = outerslot;
econtext->ecxt_scantuple = outerslot;
/* Compute the number of times to output this tuple. */
oldcxt = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
repeatstate->repeat_count =
DatumGetInt32(ExecEvalExpr(repeatstate->expr_state, econtext,
&isNull, NULL));
Assert(!isNull);
MemoryContextSwitchTo(oldcxt);
if (repeatstate->repeat_count == 0)
continue;
if (repeatstate->repeat_count > 1)
repeatstate->slot = outerslot;
do
{
econtext->group_id = repeatstate->repeat_count - 1;
econtext->grouping = node->grouping;
repeatstate->repeat_count--;
/* Check the qual until we find one output tuple. */
if (ExecQual(repeatstate->ps.qual, econtext, false))
{
Gpmon_M_Incr_Rows_Out(GpmonPktFromRepeatState(repeatstate));
CheckSendPlanStateGpmonPkt(&repeatstate->ps);
return ExecProject(repeatstate->ps.ps_ProjInfo, NULL);
}
} while (repeatstate->repeat_count > 0);
}
return NULL;
}
/* ----------------------------------------------------------------
* ExecNestLoop(node)
*
* old comments
* Returns the tuple joined from inner and outer tuples which
* satisfies the qualification clause.
*
* It scans the inner relation to join with current outer tuple.
*
* If none is found, next tuple form the outer relation is retrieved
* and the inner relation is scanned from the beginning again to join
* with the outer tuple.
*
* Nil is returned if all the remaining outer tuples are tried and
* all fail to join with the inner tuples.
*
* Nil is also returned if there is no tuple from inner realtion.
*
* Conditions:
* -- outerTuple contains current tuple from outer relation and
* the right son(inner realtion) maintains "cursor" at the tuple
* returned previously.
* This is achieved by maintaining a scan position on the outer
* relation.
*
* Initial States:
* -- the outer child and the inner child
* are prepared to return the first tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecNestLoop(NestLoop *node, Plan* parent)
{
NestLoopState *nlstate;
Plan *innerPlan;
Plan *outerPlan;
bool needNewOuterTuple;
TupleTableSlot *outerTupleSlot;
TupleTableSlot *innerTupleSlot;
List *qual;
bool qualResult;
ExprContext *econtext;
/* ----------------
* get information from the node
* ----------------
*/
ENL1_printf("getting info from node");
nlstate = node->nlstate;
qual = node->join.qual;
outerPlan = outerPlan(&node->join);
innerPlan = innerPlan(&node->join);
/* ----------------
* initialize expression context
* ----------------
*/
econtext = nlstate->jstate.cs_ExprContext;
/* ---------------- * get the current outer tuple
* ----------------
*/
outerTupleSlot = nlstate->jstate.cs_OuterTupleSlot;
econtext->ecxt_outertuple = outerTupleSlot;
/* ----------------
* Ok, everything is setup for the join so now loop until
* we return a qualifying join tuple..
* ----------------
*/
if (nlstate->jstate.cs_TupFromTlist) {
TupleTableSlot *result;
bool isDone;
result = ExecProject(nlstate->jstate.cs_ProjInfo, &isDone);
if (!isDone)
return result;
}
ENL1_printf("entering main loop");
for(;;) {
/* ----------------
* The essential idea now is to get the next inner tuple
* and join it with the current outer tuple.
* ----------------
*/
needNewOuterTuple = false;
/* ----------------
* If outer tuple is not null then that means
* we are in the middle of a scan and we should
* restore our previously saved scan position.
* ----------------
*/
if (! TupIsNull(outerTupleSlot)) {
ENL1_printf("have outer tuple, restoring outer plan");
ExecRestrPos(outerPlan);
} else {
ENL1_printf("outer tuple is nil, need new outer tuple");
needNewOuterTuple = true;
}
/* ----------------
* if we have an outerTuple, try to get the next inner tuple.
* ----------------
*/
if (!needNewOuterTuple) {
ENL1_printf("getting new inner tuple");
innerTupleSlot = ExecProcNode(innerPlan, (Plan*)node);
econtext->ecxt_innertuple = innerTupleSlot;
if (TupIsNull(innerTupleSlot)) {
ENL1_printf("no inner tuple, need new outer tuple");
needNewOuterTuple = true;
}
}
/* ----------------
* loop until we have a new outer tuple and a new
* inner tuple.
* ----------------
*/
while (needNewOuterTuple) {
/* ----------------
* now try to get the next outer tuple
* ----------------
*/
ENL1_printf("getting new outer tuple");
outerTupleSlot = ExecProcNode(outerPlan, (Plan*)node);
econtext->ecxt_outertuple = outerTupleSlot;
/* ----------------
* if there are no more outer tuples, then the join
* is complete..
* ----------------
*/
if (TupIsNull(outerTupleSlot)) {
ENL1_printf("no outer tuple, ending join");
return NULL;
}
/* ----------------
* we have a new outer tuple so we mark our position
* in the outer scan and save the outer tuple in the
* NestLoop state
* ----------------
*/
ENL1_printf("saving new outer tuple information");
ExecMarkPos(outerPlan);
nlstate->jstate.cs_OuterTupleSlot = outerTupleSlot;
/* ----------------
* now rescan the inner plan and get a new inner tuple
* ----------------
*/
ENL1_printf("rescanning inner plan");
/*
* The scan key of the inner plan might depend on the current
* outer tuple (e.g. in index scans), that's why we pass our
* expr context.
*/
ExecReScan(innerPlan, econtext, parent);
ENL1_printf("getting new inner tuple");
innerTupleSlot = ExecProcNode(innerPlan, (Plan*)node);
econtext->ecxt_innertuple = innerTupleSlot;
if (TupIsNull(innerTupleSlot)) {
ENL1_printf("couldn't get inner tuple - need new outer tuple");
} else {
ENL1_printf("got inner and outer tuples");
needNewOuterTuple = false;
}
} /* while (needNewOuterTuple) */
/* ----------------
* at this point we have a new pair of inner and outer
* tuples so we test the inner and outer tuples to see
* if they satisify the node's qualification.
* ----------------
*/
ENL1_printf("testing qualification");
qualResult = ExecQual((List*)qual, econtext);
if (qualResult) {
/* ----------------
* qualification was satisified so we project and
* return the slot containing the result tuple
* using ExecProject().
* ----------------
*/
ProjectionInfo *projInfo;
TupleTableSlot *result;
bool isDone;
ENL1_printf("qualification succeeded, projecting tuple");
projInfo = nlstate->jstate.cs_ProjInfo;
result = ExecProject(projInfo, &isDone);
nlstate->jstate.cs_TupFromTlist = !isDone;
return result;
}
/* ----------------
* qualification failed so we have to try again..
* ----------------
*/
ENL1_printf("qualification failed, looping");
}
}
/* ----------------------------------------------------------------
* ExecScan
*
* Scans the relation using the 'access method' indicated and
* returns the next qualifying tuple in the direction specified
* in the global variable ExecDirection.
* The access method returns the next tuple and execScan() is
* responsible for checking the tuple returned against the qual-clause.
*
* Conditions:
* -- the "cursor" maintained by the AMI is positioned at the tuple
* returned previously.
*
* Initial States:
* -- the relation indicated is opened for scanning so that the
* "cursor" is positioned before the first qualifying tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecScan(ScanState *node,
ExecScanAccessMtd accessMtd) /* function returning a tuple */
{
ExprContext *econtext;
List *qual;
ProjectionInfo *projInfo;
ExprDoneCond isDone;
TupleTableSlot *resultSlot;
/*
* Fetch data from node
*/
qual = node->ps.qual;
projInfo = node->ps.ps_ProjInfo;
/*
* If we have neither a qual to check nor a projection to do, just skip
* all the overhead and return the raw scan tuple.
*/
if (!qual && !projInfo)
return (*accessMtd) (node);
/*
* Check to see if we're still projecting out tuples from a previous scan
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->ps.ps_TupFromTlist)
{
Assert(projInfo); /* can't get here if not projecting */
resultSlot = ExecProject(projInfo, &isDone);
if (isDone == ExprMultipleResult)
return resultSlot;
/* Done with that source tuple... */
node->ps.ps_TupFromTlist = false;
}
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't happen
* until we're done projecting out tuples from a scan tuple.
*/
econtext = node->ps.ps_ExprContext;
ResetExprContext(econtext);
/*
* get a tuple from the access method loop until we obtain a tuple which
* passes the qualification.
*/
for (;;)
{
TupleTableSlot *slot;
CHECK_FOR_INTERRUPTS();
slot = (*accessMtd) (node);
/*
* if the slot returned by the accessMtd contains NULL, then it means
* there is nothing more to scan so we just return an empty slot,
* being careful to use the projection result slot so it has correct
* tupleDesc.
*/
if (TupIsNull(slot))
{
if (projInfo)
return ExecClearTuple(projInfo->pi_slot);
else
return slot;
}
/*
* place the current tuple into the expr context
*/
econtext->ecxt_scantuple = slot;
/*
* check that the current tuple satisfies the qual-clause
*
* check for non-nil qual here to avoid a function call to ExecQual()
* when the qual is nil ... saves only a few cycles, but they add up
* ...
*/
if (!qual || ExecQual(qual, econtext, false))
{
/*
* Found a satisfactory scan tuple.
*/
if (projInfo)
{
/*
* Form a projection tuple, store it in the result tuple slot
* and return it --- unless we find we can project no tuples
* from this scan tuple, in which case continue scan.
*/
resultSlot = ExecProject(projInfo, &isDone);
if (isDone != ExprEndResult)
{
node->ps.ps_TupFromTlist = (isDone == ExprMultipleResult);
return resultSlot;
}
}
else
{
/*
* Here, we aren't projecting, so just return scan tuple.
*/
return slot;
}
}
/*
* Tuple fails qual, so free per-tuple memory and try again.
*/
ResetExprContext(econtext);
}
}
/* ----------------------------------------------------------------
* BitmapHeapNext
*
* Retrieve next tuple from the BitmapHeapScan node's currentRelation
* ----------------------------------------------------------------
*/
static TupleTableSlot *
BitmapHeapNext(BitmapHeapScanState *node)
{
EState *estate;
ExprContext *econtext;
HeapScanDesc scan;
Index scanrelid;
TIDBitmap *tbm;
TBMIterateResult *tbmres;
OffsetNumber targoffset;
TupleTableSlot *slot;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
scan = node->ss.ss_currentScanDesc;
scanrelid = ((BitmapHeapScan *) node->ss.ps.plan)->scan.scanrelid;
tbm = node->tbm;
tbmres = node->tbmres;
/*
* Check if we are evaluating PlanQual for tuple of this relation.
* Additional checking is not good, but no other way for now. We could
* introduce new nodes for this case and handle IndexScan --> NewNode
* switching in Init/ReScan plan...
*/
if (estate->es_evTuple != NULL &&
estate->es_evTuple[scanrelid - 1] != NULL)
{
if (estate->es_evTupleNull[scanrelid - 1])
return ExecClearTuple(slot);
ExecStoreTuple(estate->es_evTuple[scanrelid - 1],
slot, InvalidBuffer, false);
/* Does the tuple meet the original qual conditions? */
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext, false))
ExecClearTuple(slot); /* would not be returned by scan */
/* Flag for the next call that no more tuples */
estate->es_evTupleNull[scanrelid - 1] = true;
return slot;
}
/*
* If we haven't yet performed the underlying index scan, do it, and
* prepare the bitmap to be iterated over.
*/
if (tbm == NULL)
{
tbm = (TIDBitmap *) MultiExecProcNode(outerPlanState(node));
if (!tbm || !IsA(tbm, TIDBitmap))
elog(ERROR, "unrecognized result from subplan");
node->tbm = tbm;
node->tbmres = tbmres = NULL;
tbm_begin_iterate(tbm);
}
for (;;)
{
Page dp;
ItemId lp;
/*
* Get next page of results if needed
*/
if (tbmres == NULL)
{
node->tbmres = tbmres = tbm_iterate(tbm);
if (tbmres == NULL)
{
/* no more entries in the bitmap */
break;
}
/*
* Ignore any claimed entries past what we think is the end of the
* relation. (This is probably not necessary given that we got at
* least AccessShareLock on the table before performing any of the
* indexscans, but let's be safe.)
*/
if (tbmres->blockno >= scan->rs_nblocks)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* Fetch the current heap page and identify candidate tuples.
*/
bitgetpage(scan, tbmres);
/*
* Set rs_cindex to first slot to examine
*/
scan->rs_cindex = 0;
}
else
{
/*
* Continuing in previously obtained page; advance rs_cindex
*/
scan->rs_cindex++;
}
/*
* Out of range? If so, nothing more to look at on this page
*/
if (scan->rs_cindex < 0 || scan->rs_cindex >= scan->rs_ntuples)
{
node->tbmres = tbmres = NULL;
continue;
}
/*
* Okay to fetch the tuple
*/
targoffset = scan->rs_vistuples[scan->rs_cindex];
dp = (Page) BufferGetPage(scan->rs_cbuf);
lp = PageGetItemId(dp, targoffset);
Assert(ItemIdIsNormal(lp));
scan->rs_ctup.t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
scan->rs_ctup.t_len = ItemIdGetLength(lp);
ItemPointerSet(&scan->rs_ctup.t_self, tbmres->blockno, targoffset);
pgstat_count_heap_fetch(scan->rs_rd);
/*
* Set up the result slot to point to this tuple. Note that the slot
* acquires a pin on the buffer.
*/
ExecStoreTuple(&scan->rs_ctup,
slot,
scan->rs_cbuf,
false);
/*
* If we are using lossy info, we have to recheck the qual conditions
* at every tuple.
*/
if (tbmres->ntuples < 0)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->bitmapqualorig, econtext, false))
{
/* Fails recheck, so drop it and loop back for another */
ExecClearTuple(slot);
continue;
}
}
/* OK to return this tuple */
return slot;
}
/*
* if we get here it means we are at the end of the scan..
*/
return ExecClearTuple(slot);
}
/* ----------------------------------------------------------------
* IndexNext
*
* Retrieve a tuple from the IndexScan node's currentRelation
* using the index specified in the IndexScanState information.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
IndexNext(IndexScanState *node)
{
EState *estate;
ExprContext *econtext;
ScanDirection direction;
IndexScanDesc scandesc;
HeapTuple tuple;
TupleTableSlot *slot;
/*
* extract necessary information from index scan node
*/
estate = node->ss.ps.state;
direction = estate->es_direction;
/* flip direction if this is an overall backward scan */
if (ScanDirectionIsBackward(((IndexScan *) node->ss.ps.plan)->indexorderdir))
{
if (ScanDirectionIsForward(direction))
direction = BackwardScanDirection;
else if (ScanDirectionIsBackward(direction))
direction = ForwardScanDirection;
}
scandesc = node->iss_ScanDesc;
econtext = node->ss.ps.ps_ExprContext;
slot = node->ss.ss_ScanTupleSlot;
/*
* ok, now that we have what we need, fetch the next tuple.
*/
while ((tuple = index_getnext(scandesc, direction)) != NULL)
{
/*
* Store the scanned tuple in the scan tuple slot of the scan state.
* Note: we pass 'false' because tuples returned by amgetnext are
* pointers onto disk pages and must not be pfree()'d.
*/
ExecStoreTuple(tuple, /* tuple to store */
slot, /* slot to store in */
scandesc->xs_cbuf, /* buffer containing tuple */
false); /* don't pfree */
/*
* If the index was lossy, we have to recheck the index quals using
* the real tuple.
*/
if (scandesc->xs_recheck)
{
econtext->ecxt_scantuple = slot;
ResetExprContext(econtext);
if (!ExecQual(node->indexqualorig, econtext, false))
continue; /* nope, so ask index for another one */
}
return slot;
}
/*
* if we get here it means the index scan failed so we are at the end of
* the scan..
*/
return ExecClearTuple(slot);
}
/*
* IndexBuildHeapScan - scan the heap relation to find tuples to be indexed
*
* This is called back from an access-method-specific index build procedure
* after the AM has done whatever setup it needs. The parent heap relation
* is scanned to find tuples that should be entered into the index. Each
* such tuple is passed to the AM's callback routine, which does the right
* things to add it to the new index. After we return, the AM's index
* build procedure does whatever cleanup is needed; in particular, it should
* close the heap and index relations.
*
* The total count of heap tuples is returned. This is for updating pg_class
* statistics. (It's annoying not to be able to do that here, but we can't
* do it until after the relation is closed.) Note that the index AM itself
* must keep track of the number of index tuples; we don't do so here because
* the AM might reject some of the tuples for its own reasons, such as being
* unable to store NULLs.
*/
double
IndexBuildHeapScan(Relation heapRelation,
Relation indexRelation,
IndexInfo *indexInfo,
IndexBuildCallback callback,
void *callback_state)
{
HeapScanDesc scan;
HeapTuple heapTuple;
TupleDesc heapDescriptor;
Datum attdata[INDEX_MAX_KEYS];
char nulls[INDEX_MAX_KEYS];
double reltuples;
List *predicate;
TupleTable tupleTable;
TupleTableSlot *slot;
EState *estate;
ExprContext *econtext;
Snapshot snapshot;
TransactionId OldestXmin;
/*
* sanity checks
*/
Assert(OidIsValid(indexRelation->rd_rel->relam));
heapDescriptor = RelationGetDescr(heapRelation);
/*
* Need an EState for evaluation of index expressions and
* partial-index predicates.
*/
estate = CreateExecutorState();
econtext = GetPerTupleExprContext(estate);
/*
* If this is a predicate (partial) index, we will need to evaluate
* the predicate using ExecQual, which requires the current tuple to
* be in a slot of a TupleTable. Likewise if there are any
* expressions.
*/
if (indexInfo->ii_Predicate != NIL || indexInfo->ii_Expressions != NIL)
{
tupleTable = ExecCreateTupleTable(1);
slot = ExecAllocTableSlot(tupleTable);
ExecSetSlotDescriptor(slot, heapDescriptor, false);
/* Arrange for econtext's scan tuple to be the tuple under test */
econtext->ecxt_scantuple = slot;
/* Set up execution state for predicate. */
predicate = (List *)
ExecPrepareExpr((Expr *) indexInfo->ii_Predicate,
estate);
}
else
{
tupleTable = NULL;
slot = NULL;
predicate = NIL;
}
/*
* Ok, begin our scan of the base relation. We use SnapshotAny
* because we must retrieve all tuples and do our own time qual
* checks.
*/
if (IsBootstrapProcessingMode())
{
snapshot = SnapshotNow;
OldestXmin = InvalidTransactionId;
}
else
{
snapshot = SnapshotAny;
OldestXmin = GetOldestXmin(heapRelation->rd_rel->relisshared);
}
scan = heap_beginscan(heapRelation, /* relation */
snapshot, /* seeself */
0, /* number of keys */
(ScanKey) NULL); /* scan key */
reltuples = 0;
/*
* Scan all tuples in the base relation.
*/
while ((heapTuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
bool tupleIsAlive;
CHECK_FOR_INTERRUPTS();
if (snapshot == SnapshotAny)
{
/* do our own time qual check */
bool indexIt;
uint16 sv_infomask;
/*
* HeapTupleSatisfiesVacuum may update tuple's hint status
* bits. We could possibly get away with not locking the
* buffer here, since caller should hold ShareLock on the
* relation, but let's be conservative about it.
*/
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
sv_infomask = heapTuple->t_data->t_infomask;
switch (HeapTupleSatisfiesVacuum(heapTuple->t_data, OldestXmin))
{
case HEAPTUPLE_DEAD:
indexIt = false;
tupleIsAlive = false;
break;
case HEAPTUPLE_LIVE:
indexIt = true;
tupleIsAlive = true;
break;
case HEAPTUPLE_RECENTLY_DEAD:
/*
* If tuple is recently deleted then we must index it
* anyway to keep VACUUM from complaining.
*/
indexIt = true;
tupleIsAlive = false;
break;
case HEAPTUPLE_INSERT_IN_PROGRESS:
/*
* Since caller should hold ShareLock or better, we
* should not see any tuples inserted by open
* transactions --- unless it's our own transaction.
* (Consider INSERT followed by CREATE INDEX within a
* transaction.) An exception occurs when reindexing
* a system catalog, because we often release lock on
* system catalogs before committing.
*/
if (!TransactionIdIsCurrentTransactionId(
HeapTupleHeaderGetXmin(heapTuple->t_data))
&& !IsSystemRelation(heapRelation))
elog(ERROR, "concurrent insert in progress");
indexIt = true;
tupleIsAlive = true;
break;
case HEAPTUPLE_DELETE_IN_PROGRESS:
/*
* Since caller should hold ShareLock or better, we
* should not see any tuples deleted by open
* transactions --- unless it's our own transaction.
* (Consider DELETE followed by CREATE INDEX within a
* transaction.) An exception occurs when reindexing
* a system catalog, because we often release lock on
* system catalogs before committing.
*/
if (!TransactionIdIsCurrentTransactionId(
HeapTupleHeaderGetXmax(heapTuple->t_data))
&& !IsSystemRelation(heapRelation))
elog(ERROR, "concurrent delete in progress");
indexIt = true;
tupleIsAlive = false;
break;
default:
elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
indexIt = tupleIsAlive = false; /* keep compiler quiet */
break;
}
/* check for hint-bit update by HeapTupleSatisfiesVacuum */
if (sv_infomask != heapTuple->t_data->t_infomask)
SetBufferCommitInfoNeedsSave(scan->rs_cbuf);
LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
if (!indexIt)
continue;
}
else
{
/* heap_getnext did the time qual check */
tupleIsAlive = true;
}
reltuples += 1;
MemoryContextReset(econtext->ecxt_per_tuple_memory);
/* Set up for predicate or expression evaluation */
if (slot)
ExecStoreTuple(heapTuple, slot, InvalidBuffer, false);
/*
* In a partial index, discard tuples that don't satisfy the
* predicate. We can also discard recently-dead tuples, since
* VACUUM doesn't complain about tuple count mismatch for partial
* indexes.
*/
if (predicate != NIL)
{
if (!tupleIsAlive)
continue;
if (!ExecQual(predicate, econtext, false))
continue;
}
/*
* For the current heap tuple, extract all the attributes we use
* in this index, and note which are null. This also performs
* evaluation of any expressions needed.
*/
FormIndexDatum(indexInfo,
heapTuple,
heapDescriptor,
estate,
attdata,
nulls);
/*
* You'd think we should go ahead and build the index tuple here,
* but some index AMs want to do further processing on the data
* first. So pass the attdata and nulls arrays, instead.
*/
/* Call the AM's callback routine to process the tuple */
callback(indexRelation, heapTuple, attdata, nulls, tupleIsAlive,
callback_state);
}
heap_endscan(scan);
if (tupleTable)
ExecDropTupleTable(tupleTable, true);
FreeExecutorState(estate);
/* These may have been pointing to the now-gone estate */
indexInfo->ii_ExpressionsState = NIL;
indexInfo->ii_PredicateState = NIL;
return reltuples;
}
