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Make 'col IS NULL' clauses be indexable conditions.

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Teodor Sigaev, with some kibitzing from Tom Lane.
This commit is contained in:
Tom Lane
2007-04-06 22:33:43 +00:00
parent 146c83c045
commit f02a82b6ad
19 changed files with 432 additions and 110 deletions
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39
src/backend/utils/adt/selfuncs.c
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@ -15,7 +15,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.231 2007/03/27 23:21:10 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.232 2007/04/06 22:33:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -4992,6 +4992,7 @@ btcostestimate(PG_FUNCTION_ARGS)
int indexcol;
bool eqQualHere;
bool found_saop;
bool found_null_op;
double num_sa_scans;
ListCell *l;
@ -5016,6 +5017,7 @@ btcostestimate(PG_FUNCTION_ARGS)
indexcol = 0;
eqQualHere = false;
found_saop = false;
found_null_op = false;
num_sa_scans = 1;
foreach(l, indexQuals)
{
@ -5025,6 +5027,7 @@ btcostestimate(PG_FUNCTION_ARGS)
*rightop;
Oid clause_op;
int op_strategy;
bool is_null_op = false;
Assert(IsA(rinfo, RestrictInfo));
clause = rinfo->clause;
@ -5051,6 +5054,17 @@ btcostestimate(PG_FUNCTION_ARGS)
clause_op = saop->opno;
found_saop = true;
}
else if (IsA(clause, NullTest))
{
NullTest *nt = (NullTest *) clause;
Assert(nt->nulltesttype == IS_NULL);
leftop = (Node *) nt->arg;
rightop = NULL;
clause_op = InvalidOid;
found_null_op = true;
is_null_op = true;
}
else
{
elog(ERROR, "unsupported indexqual type: %d",
@ -5088,11 +5102,20 @@ btcostestimate(PG_FUNCTION_ARGS)
break;
}
}
op_strategy = get_op_opfamily_strategy(clause_op,
index->opfamily[indexcol]);
Assert(op_strategy != 0); /* not a member of opfamily?? */
if (op_strategy == BTEqualStrategyNumber)
/* check for equality operator */
if (is_null_op)
{
/* IS NULL is like = for purposes of selectivity determination */
eqQualHere = true;
}
else
{
op_strategy = get_op_opfamily_strategy(clause_op,
index->opfamily[indexcol]);
Assert(op_strategy != 0); /* not a member of opfamily?? */
if (op_strategy == BTEqualStrategyNumber)
eqQualHere = true;
}
/* count up number of SA scans induced by indexBoundQuals only */
if (IsA(clause, ScalarArrayOpExpr))
{
@ -5108,12 +5131,14 @@ btcostestimate(PG_FUNCTION_ARGS)
/*
* If index is unique and we found an '=' clause for each column, we can
* just assume numIndexTuples = 1 and skip the expensive
* clauselist_selectivity calculations.
* clauselist_selectivity calculations. However, a ScalarArrayOp or
* NullTest invalidates that theory, even though it sets eqQualHere.
*/
if (index->unique &&
indexcol == index->ncolumns - 1 &&
eqQualHere &&
!found_saop)
!found_saop &&
!found_null_op)
numIndexTuples = 1.0;
else
{