/* ----------------------------------------------------------------
* 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);
}
/*
* Post vacuum, iterate over all entries in index, check if the h_tid
* of each entry exists and is not dead. For specific system tables,
* also ensure that the key in index entry matches the corresponding
* attribute in the heap tuple.
*/
void
_bt_validate_vacuum(Relation irel, Relation hrel, TransactionId oldest_xmin)
{
MIRROREDLOCK_BUFMGR_DECLARE;
BlockNumber blkno;
BlockNumber num_pages;
Buffer ibuf = InvalidBuffer;
Buffer hbuf = InvalidBuffer;
Page ipage;
BTPageOpaque opaque;
IndexTuple itup;
HeapTupleData htup;
OffsetNumber maxoff,
minoff,
offnum;
Oid ioid,
hoid;
bool isnull;
blkno = BTREE_METAPAGE + 1;
num_pages = RelationGetNumberOfBlocks(irel);
elog(LOG, "btvalidatevacuum: index %s, heap %s",
RelationGetRelationName(irel), RelationGetRelationName(hrel));
MIRROREDLOCK_BUFMGR_LOCK;
for (; blkno < num_pages; blkno++)
{
ibuf = ReadBuffer(irel, blkno);
ipage = BufferGetPage(ibuf);
opaque = (BTPageOpaque) PageGetSpecialPointer(ipage);
if (!PageIsNew(ipage))
_bt_checkpage(irel, ibuf);
if (P_ISLEAF(opaque))
{
minoff = P_FIRSTDATAKEY(opaque);
maxoff = PageGetMaxOffsetNumber(ipage);
for (offnum = minoff;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itup = (IndexTuple) PageGetItem(ipage,
PageGetItemId(ipage, offnum));
ItemPointerCopy(&itup->t_tid, &htup.t_self);
/*
* TODO: construct a tid bitmap based on index tids
* and fetch heap tids in order afterwards. That will
* also allow validating if a heap tid appears twice
* in a unique index.
*/
if (!heap_release_fetch(hrel, SnapshotAny, &htup,
&hbuf, true, NULL))
{
elog(ERROR, "btvalidatevacuum: tid (%d,%d) from index %s "
"not found in heap %s",
ItemPointerGetBlockNumber(&itup->t_tid),
ItemPointerGetOffsetNumber(&itup->t_tid),
RelationGetRelationName(irel),
RelationGetRelationName(hrel));
}
switch (HeapTupleSatisfiesVacuum(hrel, htup.t_data, oldest_xmin, hbuf))
{
case HEAPTUPLE_RECENTLY_DEAD:
case HEAPTUPLE_LIVE:
case HEAPTUPLE_INSERT_IN_PROGRESS:
case HEAPTUPLE_DELETE_IN_PROGRESS:
/* these tuples are considered alive by vacuum */
break;
case HEAPTUPLE_DEAD:
elog(ERROR, "btvalidatevacuum: vacuum did not remove "
"dead tuple (%d,%d) from heap %s and index %s",
ItemPointerGetBlockNumber(&itup->t_tid),
ItemPointerGetOffsetNumber(&itup->t_tid),
RelationGetRelationName(hrel),
RelationGetRelationName(irel));
break;
default:
elog(ERROR, "btvalidatevacuum: invalid visibility");
break;
}
switch(RelationGetRelid(irel))
{
case DatabaseOidIndexId:
case TypeOidIndexId:
case ClassOidIndexId:
case ConstraintOidIndexId:
hoid = HeapTupleGetOid(&htup);
ioid = index_getattr(itup, 1, RelationGetDescr(irel), &isnull);
if (hoid != ioid)
{
elog(ERROR,
"btvalidatevacuum: index oid(%d) != heap oid(%d)"
" tuple (%d,%d) index %s", ioid, hoid,
ItemPointerGetBlockNumber(&itup->t_tid),
ItemPointerGetOffsetNumber(&itup->t_tid),
RelationGetRelationName(irel));
}
break;
case GpRelationNodeOidIndexId:
hoid = heap_getattr(&htup, 1, RelationGetDescr(hrel), &isnull);
ioid = index_getattr(itup, 1, RelationGetDescr(irel), &isnull);
if (hoid != ioid)
{
elog(ERROR,
"btvalidatevacuum: index oid(%d) != heap oid(%d)"
" tuple (%d,%d) index %s", ioid, hoid,
ItemPointerGetBlockNumber(&itup->t_tid),
ItemPointerGetOffsetNumber(&itup->t_tid),
RelationGetRelationName(irel));
}
int4 hsegno = heap_getattr(&htup, 2, RelationGetDescr(hrel), &isnull);
int4 isegno = index_getattr(itup, 2, RelationGetDescr(irel), &isnull);
if (isegno != hsegno)
{
elog(ERROR,
"btvalidatevacuum: index segno(%d) != heap segno(%d)"
" tuple (%d,%d) index %s", isegno, hsegno,
ItemPointerGetBlockNumber(&itup->t_tid),
ItemPointerGetOffsetNumber(&itup->t_tid),
RelationGetRelationName(irel));
}
break;
default:
break;
}
if (RelationGetNamespace(irel) == PG_AOSEGMENT_NAMESPACE)
{
int4 isegno = index_getattr(itup, 1, RelationGetDescr(irel), &isnull);
int4 hsegno = heap_getattr(&htup, 1, RelationGetDescr(hrel), &isnull);
if (isegno != hsegno)
{
elog(ERROR,
"btvalidatevacuum: index segno(%d) != heap segno(%d)"
" tuple (%d,%d) index %s", isegno, hsegno,
ItemPointerGetBlockNumber(&itup->t_tid),
ItemPointerGetOffsetNumber(&itup->t_tid),
RelationGetRelationName(irel));
}
}
}
}
if (BufferIsValid(ibuf))
ReleaseBuffer(ibuf);
}
if (BufferIsValid(hbuf))
ReleaseBuffer(hbuf);
MIRROREDLOCK_BUFMGR_UNLOCK;
}
/* ----------------
* index_getnext - get the next heap tuple from a scan
*
* The result is the next heap tuple satisfying the scan keys and the
* snapshot, or NULL if no more matching tuples exist. On success,
* the buffer containing the heap tuple is pinned (the pin will be dropped
* at the next index_getnext or index_endscan).
* ----------------
*/
HeapTuple
index_getnext(IndexScanDesc scan, ScanDirection direction)
{
MIRROREDLOCK_BUFMGR_DECLARE;
HeapTuple heapTuple = &scan->xs_ctup;
FmgrInfo *procedure;
SCAN_CHECKS;
GET_SCAN_PROCEDURE(amgettuple);
/* just make sure this is false... */
scan->kill_prior_tuple = false;
for (;;)
{
bool found;
/*
* The AM's gettuple proc finds the next tuple matching the scan keys.
*/
found = DatumGetBool(FunctionCall2(procedure,
PointerGetDatum(scan),
Int32GetDatum(direction)));
/* Reset kill flag immediately for safety */
scan->kill_prior_tuple = false;
if (!found)
{
/* Release any held pin on a heap page */
if (BufferIsValid(scan->xs_cbuf))
{
ReleaseBuffer(scan->xs_cbuf);
scan->xs_cbuf = InvalidBuffer;
}
return NULL; /* failure exit */
}
pgstat_count_index_tuples(scan->indexRelation, 1);
/*
* Fetch the heap tuple and see if it matches the snapshot.
*/
if (heap_release_fetch(scan->heapRelation, scan->xs_snapshot,
heapTuple, &scan->xs_cbuf, true,
scan->indexRelation))
break;
/* Skip if no undeleted tuple at this location */
if (heapTuple->t_data == NULL)
continue;
/*
* If we can't see it, maybe no one else can either. Check to see if
* the tuple is dead to all transactions. If so, signal the index AM
* to not return it on future indexscans.
*
* We told heap_release_fetch to keep a pin on the buffer, so we can
* re-access the tuple here. But we must re-lock the buffer first.
*/
// -------- MirroredLock ----------
MIRROREDLOCK_BUFMGR_LOCK;
LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
if (HeapTupleSatisfiesVacuum(heapTuple->t_data, RecentGlobalXmin,
scan->xs_cbuf, true) == HEAPTUPLE_DEAD)
scan->kill_prior_tuple = true;
LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
MIRROREDLOCK_BUFMGR_UNLOCK;
// -------- MirroredLock ----------
}
/* Success exit */
return heapTuple;
}
