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Revise TupleTableSlot code to avoid unnecessary construction and disassembly

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of tuples when passing data up through multiple plan nodes.  A slot can now
hold either a normal "physical" HeapTuple, or a "virtual" tuple consisting
of Datum/isnull arrays.  Upper plan levels can usually just copy the Datum
arrays, avoiding heap_formtuple() and possible subsequent nocachegetattr()
calls to extract the data again.  This work extends Atsushi Ogawa's earlier
patch, which provided the key idea of adding Datum arrays to TupleTableSlots.
(I believe however that something like this was foreseen way back in Berkeley
days --- see the old comment on ExecProject.)  A test case involving many
levels of join of fairly wide tables (about 80 columns altogether) showed
about 3x overall speedup, though simple queries will probably not be
helped very much.

I have also duplicated some code in heaptuple.c in order to provide versions
of heap_formtuple and friends that use "bool" arrays to indicate null
attributes, instead of the old convention of "char" arrays containing either
'n' or ' '.  This provides a better match to the convention used by
ExecEvalExpr.  While I have not made a concerted effort to get rid of uses
of the old routines, I think they should be deprecated and eventually removed.
This commit is contained in:
Tom Lane
2005-03-16 21:38:10 +00:00
parent 712f053587
commit f97aebd162
44 changed files with 1766 additions and 934 deletions
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59
src/backend/catalog/index.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.246 2005/03/07 04:42:16 tgl Exp $
* $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.247 2005/03/16 21:38:04 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -894,8 +894,7 @@ BuildIndexInfo(Relation index)
* Construct Datum[] and nullv[] arrays for a new index tuple.
*
* indexInfo Info about the index
* heapTuple Heap tuple for which we must prepare an index entry
* heapDescriptor tupledesc for heap tuple
* slot Heap tuple for which we must prepare an index entry
* estate executor state for evaluating any index expressions
* datum Array of index Datums (output area)
* nullv Array of is-null indicators (output area)
@@ -910,8 +909,7 @@ BuildIndexInfo(Relation index)
*/
void
FormIndexDatum(IndexInfo *indexInfo,
HeapTuple heapTuple,
TupleDesc heapDescriptor,
TupleTableSlot *slot,
EState *estate,
Datum *datum,
char *nullv)
@@ -927,7 +925,7 @@ FormIndexDatum(IndexInfo *indexInfo,
ExecPrepareExpr((Expr *) indexInfo->ii_Expressions,
estate);
/* Check caller has set up context correctly */
Assert(GetPerTupleExprContext(estate)->ecxt_scantuple->val == heapTuple);
Assert(GetPerTupleExprContext(estate)->ecxt_scantuple == slot);
}
indexpr_item = list_head(indexInfo->ii_ExpressionsState);
@@ -943,7 +941,7 @@ FormIndexDatum(IndexInfo *indexInfo,
* Plain index column; get the value we need directly from the
* heap tuple.
*/
iDatum = heap_getattr(heapTuple, keycol, heapDescriptor, &isNull);
iDatum = slot_getattr(slot, keycol, &isNull);
}
else
{
@@ -1336,12 +1334,10 @@ IndexBuildHeapScan(Relation heapRelation,
{
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;
@@ -1353,41 +1349,21 @@ IndexBuildHeapScan(Relation heapRelation,
*/
Assert(OidIsValid(indexRelation->rd_rel->relam));
heapDescriptor = RelationGetDescr(heapRelation);
/*
* Need an EState for evaluation of index expressions and
* partial-index predicates.
* partial-index predicates. Also a slot to hold the current tuple.
*/
estate = CreateExecutorState();
econtext = GetPerTupleExprContext(estate);
slot = MakeSingleTupleTableSlot(RelationGetDescr(heapRelation));
/*
* 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;
/* 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;
}
/* Set up execution state for predicate, if any. */
predicate = (List *)
ExecPrepareExpr((Expr *) indexInfo->ii_Predicate,
estate);
/*
* Ok, begin our scan of the base relation. We use SnapshotAny
@@ -1511,8 +1487,7 @@ IndexBuildHeapScan(Relation heapRelation,
MemoryContextReset(econtext->ecxt_per_tuple_memory);
/* Set up for predicate or expression evaluation */
if (slot)
ExecStoreTuple(heapTuple, slot, InvalidBuffer, false);
ExecStoreTuple(heapTuple, slot, InvalidBuffer, false);
/*
* In a partial index, discard tuples that don't satisfy the
@@ -1534,8 +1509,7 @@ IndexBuildHeapScan(Relation heapRelation,
* evaluation of any expressions needed.
*/
FormIndexDatum(indexInfo,
heapTuple,
heapDescriptor,
slot,
estate,
attdata,
nulls);
@@ -1553,8 +1527,7 @@ IndexBuildHeapScan(Relation heapRelation,
heap_endscan(scan);
if (tupleTable)
ExecDropTupleTable(tupleTable, true);
ExecDropSingleTupleTableSlot(slot);
FreeExecutorState(estate);