* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.79 2006/10/04 00:29:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.79.2.1 2008/01/09 20:50:11 tgl Exp $
*
*-------------------------------------------------------------------------
*/
false);
/*
- * We can remove explicit tests of this outer-join qual, too,
- * since we now have tests forcing each of its sides to the same
- * value.
+ * We used to think we could remove explicit tests of this
+ * outer-join qual, too, since we now have tests forcing each of
+ * its sides to the same value. However, that fails in some
+ * corner cases where lower outer joins could cause one of the
+ * variables to go to NULL. (BUG in 8.2 through 8.2.6.)
+ * So now we just leave it in place, but mark it with selectivity
+ * 1.0 so that we don't underestimate the join size output ---
+ * it's mostly redundant with the constant constraints.
*/
- process_implied_equality(root,
- leftop, rightop,
- rinfo->left_sortop, rinfo->right_sortop,
- rinfo->left_relids, rinfo->right_relids,
- true);
+ rinfo->this_selec = 1.0;
/*
* And recurse to see if we can deduce anything from INNERVAR =
false);
/*
- * We can remove explicit tests of this outer-join qual, too,
- * since we now have tests forcing each of its sides to the same
- * value.
+ * We used to think we could remove explicit tests of this
+ * outer-join qual, too, since we now have tests forcing each of
+ * its sides to the same value. However, that fails in some
+ * corner cases where lower outer joins could cause one of the
+ * variables to go to NULL. (BUG in 8.2 through 8.2.6.)
+ * So now we just leave it in place, but mark it with selectivity
+ * 1.0 so that we don't underestimate the join size output ---
+ * it's mostly redundant with the constant constraints.
*/
- process_implied_equality(root,
- leftop, rightop,
- rinfo->left_sortop, rinfo->right_sortop,
- rinfo->left_relids, rinfo->right_relids,
- true);
+ rinfo->this_selec = 1.0;
/*
* And recurse to see if we can deduce anything from INNERVAR =
rinfo->right_sortop,
rinfo->right_relids,
false);
- /* ... and remove COALESCE() = CONSTANT */
- process_implied_const_eq(root, equi_key_set, relids,
- item1,
- sortop1,
- item1_relids,
- true);
/*
- * We can remove explicit tests of this outer-join qual, too,
- * since we now have tests forcing each of its sides to the
- * same value.
+ * We used to think we could remove explicit tests of this
+ * outer-join qual, too, since we now have tests forcing each
+ * of its sides to the same value. However, that fails in
+ * some corner cases where lower outer joins could cause one
+ * of the variables to go to NULL. (BUG in 8.2 through
+ * 8.2.6.) So now we just leave it in place, but mark it with
+ * selectivity 1.0 so that we don't underestimate the join
+ * size output --- it's mostly redundant with the constant
+ * constraints.
+ *
+ * Ideally we'd do that for the COALESCE() = CONSTANT rinfo,
+ * too, but we don't have easy access to that here.
*/
- process_implied_equality(root,
- leftop, rightop,
- rinfo->left_sortop,
- rinfo->right_sortop,
- rinfo->left_relids,
- rinfo->right_relids,
- true);
+ rinfo->this_selec = 1.0;
/*
* And recurse to see if we can deduce anything from LEFTVAR =
301 | | | | 1
(3 rows)
+--
+-- regression test for improper pushing of constants across outer-join clauses
+-- (as seen in early 8.2.x releases)
+--
+create temp table zt1 (f1 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "zt1_pkey" for table "zt1"
+create temp table zt2 (f2 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "zt2_pkey" for table "zt2"
+create temp table zt3 (f3 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "zt3_pkey" for table "zt3"
+insert into zt1 values(53);
+insert into zt2 values(53);
+select * from
+ zt2 left join zt3 on (f2 = f3)
+ left join zt1 on (f3 = f1)
+where f2 = 53;
+ f2 | f3 | f1
+----+----+----
+ 53 | |
+(1 row)
+
+create temp view zv1 as select *,'dummy'::text AS junk from zt1;
+select * from
+ zt2 left join zt3 on (f2 = f3)
+ left join zv1 on (f3 = f1)
+where f2 = 53;
+ f2 | f3 | f1 | junk
+----+----+----+------
+ 53 | | |
+(1 row)
+
301 | | | | 1
(3 rows)
+--
+-- regression test for improper pushing of constants across outer-join clauses
+-- (as seen in early 8.2.x releases)
+--
+create temp table zt1 (f1 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "zt1_pkey" for table "zt1"
+create temp table zt2 (f2 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "zt2_pkey" for table "zt2"
+create temp table zt3 (f3 int primary key);
+NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "zt3_pkey" for table "zt3"
+insert into zt1 values(53);
+insert into zt2 values(53);
+select * from
+ zt2 left join zt3 on (f2 = f3)
+ left join zt1 on (f3 = f1)
+where f2 = 53;
+ f2 | f3 | f1
+----+----+----
+ 53 | |
+(1 row)
+
+create temp view zv1 as select *,'dummy'::text AS junk from zt1;
+select * from
+ zt2 left join zt3 on (f2 = f3)
+ left join zv1 on (f3 = f1)
+where f2 = 53;
+ f2 | f3 | f1 | junk
+----+----+----+------
+ 53 | | |
+(1 row)
+
left join (SELECT * FROM yy where pkyy = 101) as yya ON yy.pkyy = yya.pkyy
left join xx xxa on yya.pkxx = xxa.pkxx
left join xx xxb on coalesce (xxa.pkxx, 1) = xxb.pkxx;
+
+--
+-- regression test for improper pushing of constants across outer-join clauses
+-- (as seen in early 8.2.x releases)
+--
+
+create temp table zt1 (f1 int primary key);
+create temp table zt2 (f2 int primary key);
+create temp table zt3 (f3 int primary key);
+insert into zt1 values(53);
+insert into zt2 values(53);
+
+select * from
+ zt2 left join zt3 on (f2 = f3)
+ left join zt1 on (f3 = f1)
+where f2 = 53;
+
+create temp view zv1 as select *,'dummy'::text AS junk from zt1;
+
+select * from
+ zt2 left join zt3 on (f2 = f3)
+ left join zv1 on (f3 = f1)
+where f2 = 53;
projects / postgresql / commitdiff