/* ----------------------------------------------------------------
* ExecBitmapHeapReScan(node)
* ----------------------------------------------------------------
*/
void
ExecBitmapHeapReScan(BitmapHeapScanState *node, ExprContext *exprCtxt)
{
EState *estate;
Index scanrelid;
estate = node->ss.ps.state;
scanrelid = ((BitmapHeapScan *) node->ss.ps.plan)->scan.scanrelid;
/*
* If we are being passed an outer tuple, link it into the "regular"
* per-tuple econtext for possible qual eval.
*/
if (exprCtxt != NULL)
{
ExprContext *stdecontext;
stdecontext = node->ss.ps.ps_ExprContext;
stdecontext->ecxt_outertuple = exprCtxt->ecxt_outertuple;
}
/* If this is re-scanning of PlanQual ... */
if (estate->es_evTuple != NULL &&
estate->es_evTuple[scanrelid - 1] != NULL)
{
estate->es_evTupleNull[scanrelid - 1] = false;
}
/* rescan to release any page pin */
heap_rescan(node->ss.ss_currentScanDesc, NULL);
/* undo bogus "seq scan" count (see notes in ExecInitBitmapHeapScan) */
pgstat_discount_heap_scan(&node->ss.ss_currentScanDesc->rs_pgstat_info);
if (node->tbm)
tbm_free(node->tbm);
node->tbm = NULL;
node->tbmres = NULL;
if (node->odbm)
odbm_free(node->odbm);
node->odbm = NULL;
/*
* Always rescan the input immediately, to ensure we can pass down any
* outer tuple that might be used in index quals.
*/
ExecReScan(outerPlanState(node), exprCtxt);
}
void
ReScanHeapRelation(ScanState *scanState)
{
Assert(IsA(scanState, TableScanState) ||
IsA(scanState, DynamicTableScanState));
SeqScanState *node = (SeqScanState *)scanState;
Assert(node->opaque != NULL &&
node->opaque->ss_currentScanDesc != NULL);
heap_rescan(node->opaque->ss_currentScanDesc, NULL /* new scan keys */);
node->opaque->ss_heapTupleData.bot = 0;
node->opaque->ss_heapTupleData.top = 0;
node->opaque->ss_heapTupleData.seen_EOS = 0;
node->opaque->ss_heapTupleData.last = NULL;
}
/* ----------------------------------------------------------------
* ExecReScanBitmapHeapScan(node)
* ----------------------------------------------------------------
*/
void
ExecReScanBitmapHeapScan(BitmapHeapScanState *node)
{
PlanState *outerPlan = outerPlanState(node);
/* rescan to release any page pin */
heap_rescan(node->ss.ss_currentScanDesc, NULL);
/* release bitmaps and buffers if any */
if (node->tbmiterator)
tbm_end_iterate(node->tbmiterator);
if (node->prefetch_iterator)
tbm_end_iterate(node->prefetch_iterator);
if (node->shared_tbmiterator)
tbm_end_shared_iterate(node->shared_tbmiterator);
if (node->shared_prefetch_iterator)
tbm_end_shared_iterate(node->shared_prefetch_iterator);
if (node->tbm)
tbm_free(node->tbm);
if (node->vmbuffer != InvalidBuffer)
ReleaseBuffer(node->vmbuffer);
if (node->pvmbuffer != InvalidBuffer)
ReleaseBuffer(node->pvmbuffer);
node->tbm = NULL;
node->tbmiterator = NULL;
node->tbmres = NULL;
node->prefetch_iterator = NULL;
node->initialized = false;
node->shared_tbmiterator = NULL;
node->shared_prefetch_iterator = NULL;
node->vmbuffer = InvalidBuffer;
node->pvmbuffer = InvalidBuffer;
ExecScanReScan(&node->ss);
/*
* if chgParam of subnode is not null then plan will be re-scanned by
* first ExecProcNode.
*/
if (outerPlan->chgParam == NULL)
ExecReScan(outerPlan);
}
/*
* Search the relation 'rel' for tuple using the sequential scan.
*
* If a matching tuple is found, lock it with lockmode, fill the slot with its
* contents, and return true. Return false otherwise.
*
* Note that this stops on the first matching tuple.
*
* This can obviously be quite slow on tables that have more than few rows.
*/
bool
RelationFindReplTupleSeq(Relation rel, LockTupleMode lockmode,
TupleTableSlot *searchslot, TupleTableSlot *outslot)
{
HeapTuple scantuple;
HeapScanDesc scan;
SnapshotData snap;
TransactionId xwait;
bool found;
TupleDesc desc = RelationGetDescr(rel);
Assert(equalTupleDescs(desc, outslot->tts_tupleDescriptor));
/* Start an index scan. */
InitDirtySnapshot(snap);
scan = heap_beginscan(rel, &snap, 0, NULL);
retry:
found = false;
heap_rescan(scan, NULL);
/* Try to find the tuple */
while ((scantuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
if (!tuple_equals_slot(desc, scantuple, searchslot))
continue;
found = true;
ExecStoreTuple(scantuple, outslot, InvalidBuffer, false);
ExecMaterializeSlot(outslot);
xwait = TransactionIdIsValid(snap.xmin) ?
snap.xmin : snap.xmax;
/*
* If the tuple is locked, wait for locking transaction to finish and
* retry.
*/
if (TransactionIdIsValid(xwait))
{
XactLockTableWait(xwait, NULL, NULL, XLTW_None);
goto retry;
}
}
/* Found tuple, try to lock it in the lockmode. */
if (found)
{
Buffer buf;
HeapUpdateFailureData hufd;
HTSU_Result res;
HeapTupleData locktup;
ItemPointerCopy(&outslot->tts_tuple->t_self, &locktup.t_self);
PushActiveSnapshot(GetLatestSnapshot());
res = heap_lock_tuple(rel, &locktup, GetCurrentCommandId(false),
lockmode,
LockWaitBlock,
false /* don't follow updates */ ,
&buf, &hufd);
/* the tuple slot already has the buffer pinned */
ReleaseBuffer(buf);
PopActiveSnapshot();
switch (res)
{
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
/* XXX: Improve handling here */
ereport(LOG,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("concurrent update, retrying")));
goto retry;
case HeapTupleInvisible:
elog(ERROR, "attempted to lock invisible tuple");
default:
elog(ERROR, "unexpected heap_lock_tuple status: %u", res);
break;
}
}
heap_endscan(scan);
return found;
}
