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Teach planner about some cases where a restriction clause can be

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propagated inside an outer join.  In particular, given
LEFT JOIN ON (A = B) WHERE A = constant, we cannot conclude that
B = constant at the top level (B might be null instead), but we
can nonetheless put a restriction B = constant into the quals for
B's relation, since no inner-side rows not meeting that condition
can contribute to the final result.  Similarly, given
FULL JOIN USING (J) WHERE J = constant, we can't directly conclude
that either input J variable = constant, but it's OK to push such
quals into each input rel.  Per recent gripe from Kim Bisgaard.
Along the way, remove 'valid_everywhere' flag from RestrictInfo,
as on closer analysis it was not being used for anything, and was
defined backwards anyway.
This commit is contained in:
Tom Lane
2005-07-02 23:00:42 +00:00
parent ea1e2b948d
commit cc5e80b8d1
13 changed files with 424 additions and 114 deletions
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14
src/backend/optimizer/path/indxpath.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.185 2005/06/14 04:04:30 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.186 2005/07/02 23:00:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1882,7 +1882,7 @@ expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
{
resultquals = lappend(resultquals,
make_restrictinfo(boolqual,
true, true,
true,
NULL));
continue;
}
@ -2132,7 +2132,7 @@ prefix_quals(Node *leftop, Oid opclass,
elog(ERROR, "no = operator for opclass %u", opclass);
expr = make_opclause(oproid, BOOLOID, false,
(Expr *) leftop, (Expr *) prefix_const);
result = list_make1(make_restrictinfo(expr, true, true, NULL));
result = list_make1(make_restrictinfo(expr, true, NULL));
return result;
}
@ -2147,7 +2147,7 @@ prefix_quals(Node *leftop, Oid opclass,
elog(ERROR, "no >= operator for opclass %u", opclass);
expr = make_opclause(oproid, BOOLOID, false,
(Expr *) leftop, (Expr *) prefix_const);
result = list_make1(make_restrictinfo(expr, true, true, NULL));
result = list_make1(make_restrictinfo(expr, true, NULL));
/*-------
* If we can create a string larger than the prefix, we can say
@ -2163,7 +2163,7 @@ prefix_quals(Node *leftop, Oid opclass,
elog(ERROR, "no < operator for opclass %u", opclass);
expr = make_opclause(oproid, BOOLOID, false,
(Expr *) leftop, (Expr *) greaterstr);
result = lappend(result, make_restrictinfo(expr, true, true, NULL));
result = lappend(result, make_restrictinfo(expr, true, NULL));
}
return result;
@ -2234,7 +2234,7 @@ network_prefix_quals(Node *leftop, Oid expr_op, Oid opclass, Datum rightop)
(Expr *) leftop,
(Expr *) makeConst(datatype, -1, opr1right,
false, false));
result = list_make1(make_restrictinfo(expr, true, true, NULL));
result = list_make1(make_restrictinfo(expr, true, NULL));
/* create clause "key <= network_scan_last( rightop )" */
@ -2249,7 +2249,7 @@ network_prefix_quals(Node *leftop, Oid expr_op, Oid opclass, Datum rightop)
(Expr *) leftop,
(Expr *) makeConst(datatype, -1, opr2right,
false, false));
result = lappend(result, make_restrictinfo(expr, true, true, NULL));
result = lappend(result, make_restrictinfo(expr, true, NULL));
return result;
}