From 7b99b2aede7f177e7186b8dc71822586a2d513a9 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 6 Jul 2009 02:16:14 +0000 Subject: [PATCH] Fix handling of changed-Param signaling for CteScan plan nodes. We were using the "cteParam" as a proxy for the possibility that the underlying CTE plan depends on outer-level variables or Params, but that doesn't work very well because it sometimes causes calling subqueries to be treated as SubPlans when they could be InitPlans. This is inefficient and also causes the outright failure exhibited in bug #4902. Instead, leave the cteParam out of it and copy the underlying CTE plan's extParams directly. Per bug #4902 from Marko Tiikkaja. --- src/backend/optimizer/plan/subselect.c | 34 ++++++++++++++++++--- src/test/regress/expected/with.out | 41 ++++++++++++++++++++++++++ src/test/regress/sql/with.sql | 16 ++++++++++ 3 files changed, 87 insertions(+), 4 deletions(-) diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index cdff123828..5a320c652f 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.150 2009/06/11 14:48:59 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.150.2.1 2009/07/06 02:16:14 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1916,9 +1916,35 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params) break; case T_CteScan: - context.paramids = - bms_add_member(context.paramids, - ((CteScan *) plan)->cteParam); + { + /* + * You might think we should add the node's cteParam to + * paramids, but we shouldn't because that param is just a + * linkage mechanism for multiple CteScan nodes for the same + * CTE; it is never used for changed-param signaling. What + * we have to do instead is to find the referenced CTE plan + * and incorporate its external paramids, so that the correct + * things will happen if the CTE references outer-level + * variables. See test cases for bug #4902. + */ + int plan_id = ((CteScan *) plan)->ctePlanId; + Plan *cteplan; + + /* so, do this ... */ + if (plan_id < 1 || plan_id > list_length(root->glob->subplans)) + elog(ERROR, "could not find plan for CteScan referencing plan ID %d", + plan_id); + cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1); + context.paramids = + bms_add_members(context.paramids, cteplan->extParam); + +#ifdef NOT_USED + /* ... but not this */ + context.paramids = + bms_add_member(context.paramids, + ((CteScan *) plan)->cteParam); +#endif + } break; case T_WorkTableScan: diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out index 4a2f18c9e9..98003ebe6c 100644 --- a/src/test/regress/expected/with.out +++ b/src/test/regress/expected/with.out @@ -912,3 +912,44 @@ ERROR: recursive query "foo" column 1 has type numeric(3,0) in non-recursive te LINE 2: (SELECT i::numeric(3,0) FROM (VALUES(1),(2)) t(i) ^ HINT: Cast the output of the non-recursive term to the correct type. +-- +-- test for bug #4902 +-- +with cte(foo) as ( values(42) ) values((select foo from cte)); + column1 +--------- + 42 +(1 row) + +with cte(foo) as ( select 42 ) select * from ((select foo from cte)) q; + foo +----- + 42 +(1 row) + +-- test CTE referencing an outer-level variable (to see that changed-parameter +-- signaling still works properly after fixing this bug) +select ( with cte(foo) as ( values(f1) ) + select (select foo from cte) ) +from int4_tbl; + ?column? +------------- + 0 + 123456 + -123456 + 2147483647 + -2147483647 +(5 rows) + +select ( with cte(foo) as ( values(f1) ) + values((select foo from cte)) ) +from int4_tbl; + ?column? +------------- + 0 + 123456 + -123456 + 2147483647 + -2147483647 +(5 rows) + diff --git a/src/test/regress/sql/with.sql b/src/test/regress/sql/with.sql index c736441f53..6eaa168d96 100644 --- a/src/test/regress/sql/with.sql +++ b/src/test/regress/sql/with.sql @@ -469,3 +469,19 @@ WITH RECURSIVE foo(i) AS UNION ALL SELECT (i+1)::numeric(10,0) FROM foo WHERE i < 10) SELECT * FROM foo; + +-- +-- test for bug #4902 +-- +with cte(foo) as ( values(42) ) values((select foo from cte)); +with cte(foo) as ( select 42 ) select * from ((select foo from cte)) q; + +-- test CTE referencing an outer-level variable (to see that changed-parameter +-- signaling still works properly after fixing this bug) +select ( with cte(foo) as ( values(f1) ) + select (select foo from cte) ) +from int4_tbl; + +select ( with cte(foo) as ( values(f1) ) + values((select foo from cte)) ) +from int4_tbl;