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Commitd9cb487

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committed
Better solution to the problem of labeling whole-row Datums that are
generated from subquery outputs: use the type info stored in the Varitself. To avoid making ExecEvalVar and slot_getattr more complexand slower, I split out the whole-row case into a separate ExecEval routine.
1 parent07908c9 commitd9cb487

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2 files changed

+87
-40
lines changed

2 files changed

+87
-40
lines changed

‎src/backend/access/common/heaptuple.c

Lines changed: 1 addition & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -16,7 +16,7 @@
1616
*
1717
*
1818
* IDENTIFICATION
19-
* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.101 2005/10/1918:18:32 tgl Exp $
19+
* $PostgreSQL: pgsql/src/backend/access/common/heaptuple.c,v 1.102 2005/10/1922:30:30 tgl Exp $
2020
*
2121
*-------------------------------------------------------------------------
2222
*/
@@ -27,7 +27,6 @@
2727
#include"access/tuptoaster.h"
2828
#include"catalog/pg_type.h"
2929
#include"executor/tuptable.h"
30-
#include"utils/typcache.h"
3130

3231

3332
/* ----------------------------------------------------------------
@@ -595,38 +594,6 @@ heap_getsysattr(HeapTuple tup, int attnum, TupleDesc tupleDesc, bool *isnull)
595594
caseTableOidAttributeNumber:
596595
result=ObjectIdGetDatum(tup->t_tableOid);
597596
break;
598-
599-
/*
600-
* If the attribute number is 0, then we are supposed to return
601-
* the entire tuple as a row-type Datum. (Using zero for this
602-
* purpose is unclean since it risks confusion with "invalid attr"
603-
* result codes, but it's not worth changing now.)
604-
*
605-
* We have to make a copy of the tuple so we can safely insert the
606-
* Datum overhead fields, which are not set in on-disk tuples.
607-
*
608-
* It's possible that the passed tupleDesc is a record type that
609-
* hasn't been "blessed" yet, so cover that case.
610-
*/
611-
caseInvalidAttrNumber:
612-
{
613-
HeapTupleHeaderdtup;
614-
615-
if (tupleDesc->tdtypeid==RECORDOID&&
616-
tupleDesc->tdtypmod<0)
617-
assign_record_type_typmod(tupleDesc);
618-
619-
dtup= (HeapTupleHeader)palloc(tup->t_len);
620-
memcpy((char*)dtup, (char*)tup->t_data,tup->t_len);
621-
622-
HeapTupleHeaderSetDatumLength(dtup,tup->t_len);
623-
HeapTupleHeaderSetTypeId(dtup,tupleDesc->tdtypeid);
624-
HeapTupleHeaderSetTypMod(dtup,tupleDesc->tdtypmod);
625-
626-
result=PointerGetDatum(dtup);
627-
}
628-
break;
629-
630597
default:
631598
elog(ERROR,"invalid attnum: %d",attnum);
632599
result=0;/* keep compiler quiet */

‎src/backend/executor/execQual.c

Lines changed: 86 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.182 2005/10/1918:18:33 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.183 2005/10/1922:30:30 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -64,6 +64,8 @@ static Datum ExecEvalAggref(AggrefExprState *aggref,
6464
bool*isNull,ExprDoneCond*isDone);
6565
staticDatumExecEvalVar(ExprState*exprstate,ExprContext*econtext,
6666
bool*isNull,ExprDoneCond*isDone);
67+
staticDatumExecEvalWholeRowVar(ExprState*exprstate,ExprContext*econtext,
68+
bool*isNull,ExprDoneCond*isDone);
6769
staticDatumExecEvalConst(ExprState*exprstate,ExprContext*econtext,
6870
bool*isNull,ExprDoneCond*isDone);
6971
staticDatumExecEvalParam(ExprState*exprstate,ExprContext*econtext,
@@ -448,9 +450,9 @@ ExecEvalVar(ExprState *exprstate, ExprContext *econtext,
448450
/*
449451
* Get the slot and attribute number we want
450452
*
451-
* The asserts check that references to system attributes only appear at the
452-
* level of a relation scan; at higher levels, system attributes must be
453-
* treated as ordinary variables (since we no longer have access to the
453+
* The asserts check that references to system attributes only appear at
454+
*thelevel of a relation scan; at higher levels, system attributes must
455+
*betreated as ordinary variables (since we no longer have access to the
454456
* original tuple).
455457
*/
456458
attnum=variable->varattno;
@@ -505,6 +507,77 @@ ExecEvalVar(ExprState *exprstate, ExprContext *econtext,
505507
returnslot_getattr(slot,attnum,isNull);
506508
}
507509

510+
/* ----------------------------------------------------------------
511+
*ExecEvalWholeRowVar
512+
*
513+
*Returns a Datum for a whole-row variable.
514+
*
515+
*This could be folded into ExecEvalVar, but we make it a separate
516+
*routine so as not to slow down ExecEvalVar with tests for this
517+
*uncommon case.
518+
* ----------------------------------------------------------------
519+
*/
520+
staticDatum
521+
ExecEvalWholeRowVar(ExprState*exprstate,ExprContext*econtext,
522+
bool*isNull,ExprDoneCond*isDone)
523+
{
524+
Var*variable= (Var*)exprstate->expr;
525+
TupleTableSlot*slot;
526+
HeapTupletuple;
527+
TupleDesctupleDesc;
528+
HeapTupleHeaderdtuple;
529+
530+
if (isDone)
531+
*isDone=ExprSingleResult;
532+
*isNull= false;
533+
534+
Assert(variable->varattno==InvalidAttrNumber);
535+
536+
/*
537+
* Whole-row Vars can only appear at the level of a relation scan,
538+
* never in a join.
539+
*/
540+
Assert(variable->varno!=INNER);
541+
Assert(variable->varno!=OUTER);
542+
slot=econtext->ecxt_scantuple;
543+
544+
tuple=slot->tts_tuple;
545+
tupleDesc=slot->tts_tupleDescriptor;
546+
547+
/*
548+
* We have to make a copy of the tuple so we can safely insert the
549+
* Datum overhead fields, which are not set in on-disk tuples.
550+
*/
551+
dtuple= (HeapTupleHeader)palloc(tuple->t_len);
552+
memcpy((char*)dtuple, (char*)tuple->t_data,tuple->t_len);
553+
554+
HeapTupleHeaderSetDatumLength(dtuple,tuple->t_len);
555+
556+
/*
557+
* If the Var identifies a named composite type, label the tuple
558+
* with that type; otherwise use what is in the tupleDesc.
559+
*
560+
* It's likely that the slot's tupleDesc is a record type; if so,
561+
* make sure it's been "blessed", so that the Datum can be interpreted
562+
* later.
563+
*/
564+
if (variable->vartype!=RECORDOID)
565+
{
566+
HeapTupleHeaderSetTypeId(dtuple,variable->vartype);
567+
HeapTupleHeaderSetTypMod(dtuple,variable->vartypmod);
568+
}
569+
else
570+
{
571+
if (tupleDesc->tdtypeid==RECORDOID&&
572+
tupleDesc->tdtypmod<0)
573+
assign_record_type_typmod(tupleDesc);
574+
HeapTupleHeaderSetTypeId(dtuple,tupleDesc->tdtypeid);
575+
HeapTupleHeaderSetTypMod(dtuple,tupleDesc->tdtypmod);
576+
}
577+
578+
returnPointerGetDatum(dtuple);
579+
}
580+
508581
/* ----------------------------------------------------------------
509582
*ExecEvalConst
510583
*
@@ -2841,8 +2914,15 @@ ExecInitExpr(Expr *node, PlanState *parent)
28412914
switch (nodeTag(node))
28422915
{
28432916
caseT_Var:
2844-
state= (ExprState*)makeNode(ExprState);
2845-
state->evalfunc=ExecEvalVar;
2917+
{
2918+
Var*var= (Var*)node;
2919+
2920+
state= (ExprState*)makeNode(ExprState);
2921+
if (var->varattno!=InvalidAttrNumber)
2922+
state->evalfunc=ExecEvalVar;
2923+
else
2924+
state->evalfunc=ExecEvalWholeRowVar;
2925+
}
28462926
break;
28472927
caseT_Const:
28482928
state= (ExprState*)makeNode(ExprState);

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