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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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26
src/backend/optimizer/path/indxpath.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.218 2007/03/21 22:18:12 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.219 2007/04/06 22:33:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1050,6 +1050,7 @@ match_clause_to_indexcol(IndexOptInfo *index,
* Clause must be a binary opclause, or possibly a ScalarArrayOpExpr
* (which is always binary, by definition). Or it could be a
* RowCompareExpr, which we pass off to match_rowcompare_to_indexcol().
* Or, if the index supports it, we can handle IS NULL clauses.
*/
if (is_opclause(clause))
{
@ -1083,6 +1084,15 @@ match_clause_to_indexcol(IndexOptInfo *index,
(RowCompareExpr *) clause,
outer_relids);
}
else if (index->amsearchnulls && IsA(clause, NullTest))
{
NullTest *nt = (NullTest *) clause;
if (nt->nulltesttype == IS_NULL &&
match_index_to_operand((Node *) nt->arg, indexcol, index))
return true;
return false;
}
else
return false;
@ -2102,8 +2112,8 @@ expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
}
/*
* Else it must be an opclause (usual case), ScalarArrayOp, or
* RowCompare
* Else it must be an opclause (usual case), ScalarArrayOp,
* RowCompare, or NullTest
*/
if (is_opclause(clause))
{
@ -2123,6 +2133,16 @@ expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
index,
indexcol));
}
else if (IsA(clause, NullTest))
{
Assert(index->amsearchnulls);
resultquals = lappend(resultquals,
make_restrictinfo(clause,
true,
false,
false,
NULL));
}
else
elog(ERROR, "unsupported indexqual type: %d",
(int) nodeTag(clause));