From 0a7ccee8fe9ffaff09ad45f4890a3457c69e80b7 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 17 Jul 2022 17:27:50 -0400
Subject: [PATCH] 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
---
.../postgres_fdw/expected/postgres_fdw.out | 20 +++++++++++++++++++
contrib/postgres_fdw/postgres_fdw.c | 8 ++++++++
contrib/postgres_fdw/sql/postgres_fdw.sql | 9 +++++++++
3 files changed, 37 insertions(+)
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 5f2ef88cf3..a6c1b16275 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -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
-- ===================================================================
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 955a428e3d..f3b93954ee 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -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;
}
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index ae1fc8f58b..a4f988fdb8 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -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
-- ===================================================================