/* ----------------
* ExecInitScanTupleSlot
*
* CDB: Only Scan operators should use this function. Operators other
* than scans should use ExecInitExtraTupleSlot.
*
* CDB: Some system-defined attributes are kept in the TupleTableSlot
* so they can be reused for each tuple. They're initialized here.
* During execution, Var nodes referencing system-defined attrs can
* occur only in the targetlist and qual exprs attached to a scan
* operator. Those exprs are evaluated taking their input from the
* scan operator's Scan Tuple Slot.
* ----------------
*/
void
ExecInitScanTupleSlot(EState *estate, ScanState *scanstate)
{
TupleTableSlot *slot = ExecAllocTableSlot(estate->es_tupleTable);
Scan *scan = (Scan *)scanstate->ps.plan;
RangeTblEntry *rtentry;
scanstate->ss_ScanTupleSlot = slot;
/* CDB: Does this look like a Scan operator? */
Insist(scan->scanrelid > 0 &&
scan->scanrelid <= list_length(estate->es_range_table));
/* What kind of scan? */
rtentry = rt_fetch(scan->scanrelid, estate->es_range_table);
switch (rtentry->rtekind)
{
case RTE_RELATION:
/* Set 'tableoid' sysattr to the Oid of baserel's pg_class row. */
slot->tts_tableOid = rtentry->relid;
break;
default:
break;
}
}
/* ----------------
* ExecInitExtraTupleSlot
* ----------------
*/
TupleTableSlot *
ExecInitExtraTupleSlot(EState *estate)
{
return ExecAllocTableSlot(estate->es_tupleTable);
}
/* ----------------
* ExecInitResultTupleSlot
* ----------------
*/
void
ExecInitResultTupleSlot(EState *estate, PlanState *planstate)
{
planstate->ps_ResultTupleSlot = ExecAllocTableSlot(estate->es_tupleTable);
}
CustomScanState *
ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
{
CustomScanState *css;
Relation scan_rel = NULL;
Index scanrelid = cscan->scan.scanrelid;
Index tlistvarno;
/*
* Allocate the CustomScanState object. We let the custom scan provider
* do the palloc, in case it wants to make a larger object that embeds
* CustomScanState as the first field. It must set the node tag and the
* methods field correctly at this time. Other standard fields should be
* set to zero.
*/
css = (CustomScanState *) cscan->methods->CreateCustomScanState(cscan);
Assert(IsA(css, CustomScanState));
/* ensure flags is filled correctly */
css->flags = cscan->flags;
/* fill up fields of ScanState */
css->ss.ps.plan = &cscan->scan.plan;
css->ss.ps.state = estate;
/* create expression context for node */
ExecAssignExprContext(estate, &css->ss.ps);
#ifdef PG95
css->ss.ps.ps_TupFromTlist = false;
#endif
/* initialize child expressions */
css->ss.ps.targetlist = (List *)
ExecInitExpr((Expr *) cscan->scan.plan.targetlist,
(PlanState *) css);
css->ss.ps.qual = (List *)
ExecInitExpr((Expr *) cscan->scan.plan.qual,
(PlanState *) css);
/* tuple table initialization */
#ifndef PG95
if (((Scan*)css->ss.ps.plan)->scanrelid) {
// For table scans
ExecInitScanTupleSlot(estate, &css->ss);
}
else {
// For tuple-table-slot scans (typically over Motion nodes)
css->ss.ss_ScanTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable);
}
#else
ExecInitScanTupleSlot(estate, &css->ss);
#endif
ExecInitResultTupleSlot(estate, &css->ss.ps);
/*
* open the base relation, if any, and acquire an appropriate lock on it
*/
if (scanrelid > 0)
{
scan_rel = ExecOpenScanRelation(estate
, scanrelid
#ifdef PG95
, eflags
#endif
);
css->ss.ss_currentRelation = scan_rel;
}
/*
* Determine the scan tuple type. If the custom scan provider provided a
* targetlist describing the scan tuples, use that; else use base
* relation's rowtype.
*/
if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
{
// index-only scan? GP doesn't define INDEX_VAR
TupleDesc scan_tupdesc;
scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist, false);
ExecAssignScanType(&css->ss, scan_tupdesc);
#ifdef PG95
/* Node's targetlist will contain Vars with varno = INDEX_VAR */
tlistvarno = INDEX_VAR;
#endif
}
else
{
ExecAssignScanType(&css->ss, RelationGetDescr(scan_rel));
/* Node's targetlist will contain Vars with varno = scanrelid */
tlistvarno = scanrelid;
}
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&css->ss.ps);
#ifdef PG95
ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
#else
ExecAssignScanProjectionInfo(&css->ss);
#endif
/*
* The callback of custom-scan provider applies the final initialization
* of the custom-scan-state node according to its logic.
*/
css->methods->BeginCustomScan(css, estate, eflags);
return css;
}
/* ----------------
* ExecInitScanTupleSlot
* ----------------
*/
void
ExecInitScanTupleSlot(EState *estate, ScanState *scanstate)
{
scanstate->ss_ScanTupleSlot = ExecAllocTableSlot(estate->es_tupleTable);
}
/*
* 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;
}
