postgres_fdw: set search_path to 'pg_catalog' while deparsing constants.

The motivation for this is to ensure successful transmission of the
values of constants of regconfig and other reg* types.  The remote
will be reading them with search_path = 'pg_catalog', so schema
qualification is necessary when referencing objects in other schemas.

Per bug #17483 from Emmanuel Quincerot.  Back-patch to all supported
versions.  (There's some other stuff to do here, but it's less
back-patchable.)

Discussion: https://postgr.es/m/1423433.1652722406@sss.pgh.pa.us
This commit is contained in:
Tom Lane 2022-07-17 17:27:50 -04:00
parent e993166d71
commit 0a7ccee8fe
3 changed files with 37 additions and 0 deletions

View File

@ -1163,6 +1163,26 @@ SELECT * FROM ft1 WHERE CASE c3 COLLATE "C" WHEN c6 THEN true ELSE c3 < 'bar' EN
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
(4 rows)
-- check schema-qualification of regconfig constant
CREATE TEXT SEARCH CONFIGURATION public.custom_search
(COPY = pg_catalog.english);
EXPLAIN (VERBOSE, COSTS OFF)
SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------
Foreign Scan on public.ft1
Output: c1, to_tsvector('custom_search'::regconfig, c3)
Remote SQL: SELECT "C 1", c3 FROM "S 1"."T 1" WHERE (("C 1" = 642)) AND ((length(to_tsvector('public.custom_search'::regconfig, c3)) > 0))
(3 rows)
SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
c1 | to_tsvector
-----+-------------
642 | '00642':1
(1 row)
-- ===================================================================
-- JOIN queries
-- ===================================================================

View File

@ -3896,6 +3896,14 @@ set_transmission_modes(void)
PGC_USERSET, PGC_S_SESSION,
GUC_ACTION_SAVE, true, 0, false);
/*
* In addition force restrictive search_path, in case there are any
* regproc or similar constants to be printed.
*/
(void) set_config_option("search_path", "pg_catalog",
PGC_USERSET, PGC_S_SESSION,
GUC_ACTION_SAVE, true, 0, false);
return nestlevel;
}

View File

@ -442,6 +442,15 @@ SELECT * FROM ft1 WHERE CASE c3 WHEN c6 THEN true ELSE c3 < 'bar' END;
EXPLAIN (VERBOSE, COSTS OFF)
SELECT * FROM ft1 WHERE CASE c3 COLLATE "C" WHEN c6 THEN true ELSE c3 < 'bar' END;
-- check schema-qualification of regconfig constant
CREATE TEXT SEARCH CONFIGURATION public.custom_search
(COPY = pg_catalog.english);
EXPLAIN (VERBOSE, COSTS OFF)
SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
SELECT c1, to_tsvector('custom_search'::regconfig, c3) FROM ft1
WHERE c1 = 642 AND length(to_tsvector('custom_search'::regconfig, c3)) > 0;
-- ===================================================================
-- JOIN queries
-- ===================================================================