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

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index fa9674d1efa89383a63e65dcf9ae0ce4be8b20b2..f63636bba3bbb5890d77fa28ac61f239e4edf054 100644 (file)
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -1067,6 +1067,26 @@ SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
   1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
 (1 row)
 
+-- 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
 -- ===================================================================

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 0e24ed2a4879fe2d365d5baae1f03af8856ce845..485171db926f34e8aece88010a4586300e4ce2a9 100644 (file)
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -3899,6 +3899,14 @@ 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;
 }
 

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 89de85c03e3353190ffdf934a639bc8b80a054c2..adb32e95f214f8d905a6386d6afd60341ac25ad6 100644 (file)
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -408,6 +408,15 @@ EXPLAIN (VERBOSE, COSTS OFF)
   SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
 SELECT * FROM ft1 t1 WHERE t1.c1 === t1.c2 order by t1.c2 limit 1;
 
+-- 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
 -- ===================================================================