Invalidate cached plans on FDW option changes.

tglsfdc · tglsfdc · commit 4103a2f200d6 · 2017-01-06T14:12:52.000-05:00
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
@@ -2479,12 +2479,100 @@ 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                                       
+----------------------------------------------------------------------------------------
+ Aggregate
+   Output: count(c3)
+   ->  Foreign Scan on public.ft1 t1
+         Output: c3
+         Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE (("C 1" OPERATOR(public.===) c2))
+(5 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, 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
@@ -570,12 +570,35 @@ 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, should not be sent to remote
 EXPLAIN (VERBOSE, COSTS OFF)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
@@ -11313,6 +11313,12 @@ 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
@@ -119,6 +119,8 @@ 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);
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -119,6 +119,8 @@ InitPlanCache(void)`
`119`	`119`	`CacheRegisterSyscacheCallback(NAMESPACEOID, PlanCacheSysCallback, (Datum) 0);`
`120`	`120`	`CacheRegisterSyscacheCallback(OPEROID, PlanCacheSysCallback, (Datum) 0);`
`121`	`121`	`CacheRegisterSyscacheCallback(AMOPOPID, PlanCacheSysCallback, (Datum) 0);`
	`122`	`+ CacheRegisterSyscacheCallback(FOREIGNSERVEROID, PlanCacheSysCallback, (Datum) 0);`
	`123`	`+ CacheRegisterSyscacheCallback(FOREIGNDATAWRAPPEROID, PlanCacheSysCallback, (Datum) 0);`
`122`	`124`	`}`
`123`	`125`
`124`	`126`	`/*`