Invalidate cached plans on FDW option changes.

This fixes problems where a plan must change but fails to do so,
as seen in a bug report from Rajkumar Raghuwanshi.

For ALTER FOREIGN TABLE OPTIONS, do this through the standard method of
forcing a relcache flush on the table.  For ALTER FOREIGN DATA WRAPPER
and ALTER SERVER, just flush the whole plan cache on any change in
pg_foreign_data_wrapper or pg_foreign_server.  That matches the way
we handle some other low-probability cases such as opclass changes, and
it's unclear that the case arises often enough to be worth working harder.
Besides, that gives a patch that is simple enough to back-patch with
confidence.

Back-patch to 9.3.  In principle we could apply the code change to 9.2 as
well, but (a) we lack postgres_fdw to test it with, (b) it's doubtful that
anyone is doing anything exciting enough with FDWs that far back to need
this desperately, and (c) the patch doesn't apply cleanly.

Patch originally by Amit Langote, reviewed by Etsuro Fujita and Ashutosh
Bapat, who each contributed substantial changes as well.

Discussion: https://postgr.es/m/CAKcux6m5cA6rRPTKkqVdJ-R=KKDfe35Q_ZuUqxDSV_4hwga=og@mail.gmail.com

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index aceef406ae5e98b9fd02bae006d04961111c48d3..0ac5c10ddd7de49dc95f8f9feadd08939891fbb5 100644 (file)
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -853,12 +853,69 @@ EXECUTE st5('foo', 1);
   1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
 (1 row)
 
+-- altering FDW options requires replanning
+PREPARE st6 AS SELECT * FROM ft1 t1 WHERE t1.c1 = t1.c2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st6;
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = c2))
+(3 rows)
+
+PREPARE st7 AS INSERT INTO ft1 (c1,c2,c3) VALUES (1001,101,'foo');
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st7;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.ft1
+   Remote SQL: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+   ->  Result
+         Output: NULL::integer, 1001, 101, 'foo'::text, NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying, 'ft1       '::character(10), NULL::user_enum
+(4 rows)
+
+ALTER TABLE "S 1"."T 1" RENAME TO "T 0";
+ALTER FOREIGN TABLE ft1 OPTIONS (SET table_name 'T 0');
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st6;
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1 t1
+   Output: c1, c2, c3, c4, c5, c6, c7, c8
+   Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 0" WHERE (("C 1" = c2))
+(3 rows)
+
+EXECUTE st6;
+ c1 | c2 |  c3   |              c4              |            c5            | c6 |     c7     | c8  
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+  1 |  1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1  | 1          | foo
+  2 |  2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2  | 2          | foo
+  3 |  3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3  | 3          | foo
+  4 |  4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4  | 4          | foo
+  5 |  5 | 00005 | Tue Jan 06 00:00:00 1970 PST | Tue Jan 06 00:00:00 1970 | 5  | 5          | foo
+  6 |  6 | 00006 | Wed Jan 07 00:00:00 1970 PST | Wed Jan 07 00:00:00 1970 | 6  | 6          | foo
+  7 |  7 | 00007 | Thu Jan 08 00:00:00 1970 PST | Thu Jan 08 00:00:00 1970 | 7  | 7          | foo
+  8 |  8 | 00008 | Fri Jan 09 00:00:00 1970 PST | Fri Jan 09 00:00:00 1970 | 8  | 8          | foo
+  9 |  9 | 00009 | Sat Jan 10 00:00:00 1970 PST | Sat Jan 10 00:00:00 1970 | 9  | 9          | foo
+(9 rows)
+
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st7;
+                                                                                           QUERY PLAN                                                                                            
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ Insert on public.ft1
+   Remote SQL: INSERT INTO "S 1"."T 0"("C 1", c2, c3, c4, c5, c6, c7, c8) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+   ->  Result
+         Output: NULL::integer, 1001, 101, 'foo'::text, NULL::timestamp with time zone, NULL::timestamp without time zone, NULL::character varying, 'ft1       '::character(10), NULL::user_enum
+(4 rows)
+
+ALTER TABLE "S 1"."T 0" RENAME TO "T 1";
+ALTER FOREIGN TABLE ft1 OPTIONS (SET table_name 'T 1');
 -- cleanup
 DEALLOCATE st1;
 DEALLOCATE st2;
 DEALLOCATE st3;
 DEALLOCATE st4;
 DEALLOCATE st5;
+DEALLOCATE st6;
+DEALLOCATE st7;
 -- System columns, except ctid, should not be sent to remote
 EXPLAIN (VERBOSE, COSTS false)
 SELECT * FROM ft1 t1 WHERE t1.tableoid = 'pg_class'::regclass LIMIT 1;

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 4bf66ad36a0284a293afc286327fe7791cca716b..5422d65c633d1b8026563ecb5cc528dd513b188a 100644 (file)
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -246,12 +246,27 @@ EXPLAIN (VERBOSE, COSTS false) EXECUTE st5('foo', 1);
 EXPLAIN (VERBOSE, COSTS false) EXECUTE st5('foo', 1);
 EXECUTE st5('foo', 1);
 
+-- altering FDW options requires replanning
+PREPARE st6 AS SELECT * FROM ft1 t1 WHERE t1.c1 = t1.c2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st6;
+PREPARE st7 AS INSERT INTO ft1 (c1,c2,c3) VALUES (1001,101,'foo');
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st7;
+ALTER TABLE "S 1"."T 1" RENAME TO "T 0";
+ALTER FOREIGN TABLE ft1 OPTIONS (SET table_name 'T 0');
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st6;
+EXECUTE st6;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st7;
+ALTER TABLE "S 1"."T 0" RENAME TO "T 1";
+ALTER FOREIGN TABLE ft1 OPTIONS (SET table_name 'T 1');
+
 -- cleanup
 DEALLOCATE st1;
 DEALLOCATE st2;
 DEALLOCATE st3;
 DEALLOCATE st4;
 DEALLOCATE st5;
+DEALLOCATE st6;
+DEALLOCATE st7;
 
 -- System columns, except ctid, should not be sent to remote
 EXPLAIN (VERBOSE, COSTS false)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8f0e7bb2945de83922da23ec726746137f878d37..2e7d4f4e7d1a3a1bd99fb24b09bc7962cab3fd2a 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -10747,6 +10747,12 @@ ATExecGenericOptions(Relation rel, List *options)
    simple_heap_update(ftrel, &tuple->t_self, tuple);
    CatalogUpdateIndexes(ftrel, tuple);
 
+   /*
+    * Invalidate relcache so that all sessions will refresh any cached plans
+    * that might depend on the old options.
+    */
+   CacheInvalidateRelcache(rel);
+
    InvokeObjectPostAlterHook(ForeignTableRelationId,
                              RelationGetRelid(rel), 0);
 

diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index a7257e3a7fea94b06ac6481337995e806512ef28..1c6ac5f9416569434c3734d145768d7c44f39f82 100644 (file)
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -117,6 +117,8 @@ InitPlanCache(void)
    CacheRegisterSyscacheCallback(NAMESPACEOID, PlanCacheSysCallback, (Datum) 0);
    CacheRegisterSyscacheCallback(OPEROID, PlanCacheSysCallback, (Datum) 0);
    CacheRegisterSyscacheCallback(AMOPOPID, PlanCacheSysCallback, (Datum) 0);
+   CacheRegisterSyscacheCallback(FOREIGNSERVEROID, PlanCacheSysCallback, (Datum) 0);
+   CacheRegisterSyscacheCallback(FOREIGNDATAWRAPPEROID, PlanCacheSysCallback, (Datum) 0);
 }
 
 /*