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 785f520c4b127f64493eeba72fac29938faabbe1..0045f3fef8ded81914cb817b2d88e528dfac0b98 100644 (file)
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -3575,12 +3575,99 @@ 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');
+PREPARE st8 AS SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st8;
+                                       QUERY PLAN                                        
+-----------------------------------------------------------------------------------------
+ Foreign Scan
+   Output: (count(c3))
+   Relations: Aggregate on (public.ft1 t1)
+   Remote SQL: SELECT count(c3) FROM "S 1"."T 1" WHERE (("C 1" OPERATOR(public.===) c2))
+(4 rows)
+
+ALTER SERVER loopback OPTIONS (DROP extensions);
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st8;
+                        QUERY PLAN                         
+-----------------------------------------------------------
+ Aggregate
+   Output: count(c3)
+   ->  Foreign Scan on public.ft1 t1
+         Output: c3
+         Filter: (t1.c1 === t1.c2)
+         Remote SQL: SELECT "C 1", c2, c3 FROM "S 1"."T 1"
+(6 rows)
+
+EXECUTE st8;
+ count 
+-------
+     9
+(1 row)
+
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
 -- cleanup
 DEALLOCATE st1;
 DEALLOCATE st2;
 DEALLOCATE st3;
 DEALLOCATE st4;
 DEALLOCATE st5;
+DEALLOCATE st6;
+DEALLOCATE st7;
+DEALLOCATE st8;
 -- System columns, except ctid and oid, should not be sent to remote
 EXPLAIN (VERBOSE, COSTS OFF)
 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 f48743c390d80990a408bfeee7724baf46c4a7f1..919177649ed37751652b505463bd8fda1a8e43fb 100644 (file)
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -881,12 +881,35 @@ EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st5('foo', 1);
 EXPLAIN (VERBOSE, COSTS OFF) 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');
+
+PREPARE st8 AS SELECT count(c3) FROM ft1 t1 WHERE t1.c1 === t1.c2;
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st8;
+ALTER SERVER loopback OPTIONS (DROP extensions);
+EXPLAIN (VERBOSE, COSTS OFF) EXECUTE st8;
+EXECUTE st8;
+ALTER SERVER loopback OPTIONS (ADD extensions 'postgres_fdw');
+
 -- cleanup
 DEALLOCATE st1;
 DEALLOCATE st2;
 DEALLOCATE st3;
 DEALLOCATE st4;
 DEALLOCATE st5;
+DEALLOCATE st6;
+DEALLOCATE st7;
+DEALLOCATE st8;
 
 -- System columns, except ctid and oid, should not be sent to remote
 EXPLAIN (VERBOSE, COSTS OFF)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index c91bcb411a7dd593e22942c823c02de0c0afd20d..cffe2751790bd5e5f1367325e9488c373f463add 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -11940,6 +11940,12 @@ 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 29641366c06e4516ff044fa0ec37bc82f3c5ad75..e48a878dc2a99eaa4b9e25d52f6f70de6d32b272 100644 (file)
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -118,6 +118,8 @@ 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);
 }
 
 /*