From 971faefc240bf214076e529773c7ca690c5e053d Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Mon, 24 Jul 2017 15:57:24 -0400 Subject: [PATCH] When WCOs are present, disable direct foreign table modification. If the user modifies a view that has CHECK OPTIONs and this gets translated into a modification to an underlying relation which happens to be a foreign table, the check options should be enforced. In the normal code path, that was happening properly, but it was not working properly for "direct" modification because the whole operation gets pushed to the remote side in that case and we never have an option to enforce the constraint against individual tuples. Fix by disabling direct modification when there is a need to enforce CHECK OPTIONs. Etsuro Fujita, reviewed by Kyotaro Horiguchi and by me. Discussion: http://postgr.es/m/f8a48f54-6f02-9c8a-5250-9791603171ee@lab.ntt.co.jp --- .../postgres_fdw/expected/postgres_fdw.out | 60 +++++++++++++++++++ contrib/postgres_fdw/sql/postgres_fdw.sql | 24 ++++++++ doc/src/sgml/postgres-fdw.sgml | 6 +- src/backend/optimizer/plan/createplan.c | 7 ++- 4 files changed, 93 insertions(+), 4 deletions(-) diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out index e9addade26..20ea7c0308 100644 --- a/contrib/postgres_fdw/expected/postgres_fdw.out +++ b/contrib/postgres_fdw/expected/postgres_fdw.out @@ -4653,6 +4653,66 @@ INSERT INTO ft1(c1, c2) VALUES(1111, 2); UPDATE ft1 SET c2 = c2 + 1 WHERE c1 = 1; ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2negative; -- =================================================================== +-- test WITH CHECK OPTION constraints +-- =================================================================== +CREATE TABLE base_tbl (a int, b int); +CREATE FOREIGN TABLE foreign_tbl (a int, b int) + SERVER loopback OPTIONS(table_name 'base_tbl'); +CREATE VIEW rw_view AS SELECT * FROM foreign_tbl + WHERE a < b WITH CHECK OPTION; +\d+ rw_view + View "public.rw_view" + Column | Type | Modifiers | Storage | Description +--------+---------+-----------+---------+------------- + a | integer | | plain | + b | integer | | plain | +View definition: + SELECT foreign_tbl.a, + foreign_tbl.b + FROM foreign_tbl + WHERE foreign_tbl.a < foreign_tbl.b; +Options: check_option=cascaded + +INSERT INTO rw_view VALUES (0, 10); -- ok +INSERT INTO rw_view VALUES (10, 0); -- should fail +ERROR: new row violates check option for view "rw_view" +DETAIL: Failing row contains (10, 0). +EXPLAIN (VERBOSE, COSTS OFF) +UPDATE rw_view SET b = 20 WHERE a = 0; -- not pushed down + QUERY PLAN +-------------------------------------------------------------------------------------------------- + Update on public.foreign_tbl + Remote SQL: UPDATE public.base_tbl SET b = $2 WHERE ctid = $1 + -> Foreign Scan on public.foreign_tbl + Output: foreign_tbl.a, 20, foreign_tbl.ctid + Remote SQL: SELECT a, ctid FROM public.base_tbl WHERE ((a < b)) AND ((a = 0)) FOR UPDATE +(5 rows) + +UPDATE rw_view SET b = 20 WHERE a = 0; -- ok +EXPLAIN (VERBOSE, COSTS OFF) +UPDATE rw_view SET b = -20 WHERE a = 0; -- not pushed down + QUERY PLAN +-------------------------------------------------------------------------------------------------- + Update on public.foreign_tbl + Remote SQL: UPDATE public.base_tbl SET b = $2 WHERE ctid = $1 + -> Foreign Scan on public.foreign_tbl + Output: foreign_tbl.a, '-20'::integer, foreign_tbl.ctid + Remote SQL: SELECT a, ctid FROM public.base_tbl WHERE ((a < b)) AND ((a = 0)) FOR UPDATE +(5 rows) + +UPDATE rw_view SET b = -20 WHERE a = 0; -- should fail +ERROR: new row violates check option for view "rw_view" +DETAIL: Failing row contains (0, -20). +SELECT * FROM foreign_tbl; + a | b +---+---- + 0 | 20 +(1 row) + +DROP FOREIGN TABLE foreign_tbl CASCADE; +NOTICE: drop cascades to view rw_view +DROP TABLE base_tbl; +-- =================================================================== -- test serial columns (ie, sequence-based defaults) -- =================================================================== create table loc1 (f1 serial, f2 text); diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql index a43115a35a..525da8c95f 100644 --- a/contrib/postgres_fdw/sql/postgres_fdw.sql +++ b/contrib/postgres_fdw/sql/postgres_fdw.sql @@ -842,6 +842,30 @@ INSERT INTO ft1(c1, c2) VALUES(1111, 2); UPDATE ft1 SET c2 = c2 + 1 WHERE c1 = 1; ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2negative; +-- =================================================================== +-- test WITH CHECK OPTION constraints +-- =================================================================== + +CREATE TABLE base_tbl (a int, b int); +CREATE FOREIGN TABLE foreign_tbl (a int, b int) + SERVER loopback OPTIONS(table_name 'base_tbl'); +CREATE VIEW rw_view AS SELECT * FROM foreign_tbl + WHERE a < b WITH CHECK OPTION; +\d+ rw_view + +INSERT INTO rw_view VALUES (0, 10); -- ok +INSERT INTO rw_view VALUES (10, 0); -- should fail +EXPLAIN (VERBOSE, COSTS OFF) +UPDATE rw_view SET b = 20 WHERE a = 0; -- not pushed down +UPDATE rw_view SET b = 20 WHERE a = 0; -- ok +EXPLAIN (VERBOSE, COSTS OFF) +UPDATE rw_view SET b = -20 WHERE a = 0; -- not pushed down +UPDATE rw_view SET b = -20 WHERE a = 0; -- should fail +SELECT * FROM foreign_tbl; + +DROP FOREIGN TABLE foreign_tbl CASCADE; +DROP TABLE base_tbl; + -- =================================================================== -- test serial columns (ie, sequence-based defaults) -- =================================================================== diff --git a/doc/src/sgml/postgres-fdw.sgml b/doc/src/sgml/postgres-fdw.sgml index b31f3731e4..a6c56d1f63 100644 --- a/doc/src/sgml/postgres-fdw.sgml +++ b/doc/src/sgml/postgres-fdw.sgml @@ -488,8 +488,10 @@ postgres_fdw attempts to optimize the query execution by sending the whole query to the remote server if there are no query WHERE clauses that cannot be sent to the remote server, - no local joins for the query, and no row-level local BEFORE or - AFTER triggers on the target table. In UPDATE, + no local joins for the query, no row-level local BEFORE or + AFTER triggers on the target table, and no + CHECK OPTION constraints from parent views. + In UPDATE, expressions to assign to target columns must use only built-in data types, IMMUTABLE operators, or IMMUTABLE functions, to reduce the risk of misexecution of the query. diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 6f1166b703..e230329a45 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -6145,8 +6145,10 @@ make_modifytable(PlannerInfo *root, } /* - * If the target foreign table has any row-level triggers, we can't - * modify the foreign table directly. + * Try to modify the foreign table directly if (1) the FDW provides + * callback functions needed for that, (2) there are no row-level + * triggers on the foreign table, and (3) there are no WITH CHECK + * OPTIONs from parent views. */ direct_modify = false; if (fdwroutine != NULL && @@ -6154,6 +6156,7 @@ make_modifytable(PlannerInfo *root, fdwroutine->BeginDirectModify != NULL && fdwroutine->IterateDirectModify != NULL && fdwroutine->EndDirectModify != NULL && + withCheckOptionLists == NIL && !has_row_triggers(root, rti, operation)) direct_modify = fdwroutine->PlanDirectModify(root, node, rti, i); if (direct_modify)