On 2016/03/10 2:56, Robert Haas wrote:
I see that you went and changed all of the places that tested for !=
CMD_SELECT and made them test for == CMD_INSERT || == CMD_UPDATE || ==
CMD_DELETE instead.  I think that's the wrong direction.  I think that
we should use the != CMD_SELECT version of the test everywhere.
That's a single test instead of three, so marginally faster, and maybe
marginally more future-proof.

I think deparsePushedDownUpdateSql should be renamed to use the new
"direct modify" naming, like deparseDirectUpdateSql, maybe.

I would suggest not numbering the tests in postgresPlanDirectModify.
That just becomes a nuisance to keep up to date as things change.

Agreed. I updated the patch to address these comments. Attached is the updated version of the patch.

Best regards,
Etsuro Fujita
*** a/contrib/postgres_fdw/deparse.c
--- b/contrib/postgres_fdw/deparse.c
***************
*** 1315,1320 **** deparseUpdateSql(StringInfo buf, PlannerInfo *root,
--- 1315,1383 ----
  }
  
  /*
+  * deparse remote UPDATE statement
+  *
+  * The statement text is appended to buf, and we also create an integer List
+  * of the columns being retrieved by RETURNING (if any), which is returned
+  * to *retrieved_attrs.
+  */
+ void
+ deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
+ 					   Index rtindex, Relation rel,
+ 					   List *targetlist,
+ 					   List *targetAttrs,
+ 					   List *remote_conds,
+ 					   List **params_list,
+ 					   List *returningList,
+ 					   List **retrieved_attrs)
+ {
+ 	RelOptInfo *baserel = root->simple_rel_array[rtindex];
+ 	deparse_expr_cxt context;
+ 	int			nestlevel;
+ 	bool		first;
+ 	ListCell   *lc;
+ 
+ 	/* Set up context struct for recursion */
+ 	context.root = root;
+ 	context.foreignrel = baserel;
+ 	context.buf = buf;
+ 	context.params_list = params_list;
+ 
+ 	appendStringInfoString(buf, "UPDATE ");
+ 	deparseRelation(buf, rel);
+ 	appendStringInfoString(buf, " SET ");
+ 
+ 	/* Make sure any constants in the exprs are printed portably */
+ 	nestlevel = set_transmission_modes();
+ 
+ 	first = true;
+ 	foreach(lc, targetAttrs)
+ 	{
+ 		int			attnum = lfirst_int(lc);
+ 		TargetEntry *tle = get_tle_by_resno(targetlist, attnum);
+ 
+ 		if (!first)
+ 			appendStringInfoString(buf, ", ");
+ 		first = false;
+ 
+ 		deparseColumnRef(buf, rtindex, attnum, root, false);
+ 		appendStringInfoString(buf, " = ");
+ 		deparseExpr((Expr *) tle->expr, &context);
+ 	}
+ 
+ 	reset_transmission_modes(nestlevel);
+ 
+ 	if (remote_conds)
+ 	{
+ 		appendStringInfo(buf, " WHERE ");
+ 		appendConditions(remote_conds, &context);
+ 	}
+ 
+ 	deparseReturningList(buf, root, rtindex, rel, false,
+ 						 returningList, retrieved_attrs);
+ }
+ 
+ /*
   * deparse remote DELETE statement
   *
   * The statement text is appended to buf, and we also create an integer List
***************
*** 1337,1342 **** deparseDeleteSql(StringInfo buf, PlannerInfo *root,
--- 1400,1442 ----
  }
  
  /*
+  * deparse remote DELETE statement
+  *
+  * The statement text is appended to buf, and we also create an integer List
+  * of the columns being retrieved by RETURNING (if any), which is returned
+  * to *retrieved_attrs.
+  */
+ void
+ deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
+ 					   Index rtindex, Relation rel,
+ 					   List *remote_conds,
+ 					   List **params_list,
+ 					   List *returningList,
+ 					   List **retrieved_attrs)
+ {
+ 	RelOptInfo *baserel = root->simple_rel_array[rtindex];
+ 	deparse_expr_cxt context;
+ 
+ 	/* Set up context struct for recursion */
+ 	context.root = root;
+ 	context.foreignrel = baserel;
+ 	context.buf = buf;
+ 	context.params_list = params_list;
+ 
+ 	appendStringInfoString(buf, "DELETE FROM ");
+ 	deparseRelation(buf, rel);
+ 
+ 	if (remote_conds)
+ 	{
+ 		appendStringInfo(buf, " WHERE ");
+ 		appendConditions(remote_conds, &context);
+ 	}
+ 
+ 	deparseReturningList(buf, root, rtindex, rel, false,
+ 						 returningList, retrieved_attrs);
+ }
+ 
+ /*
   * Add a RETURNING clause, if needed, to an INSERT/UPDATE/DELETE.
   */
  static void
*** a/contrib/postgres_fdw/expected/postgres_fdw.out
--- b/contrib/postgres_fdw/expected/postgres_fdw.out
***************
*** 2259,2265 **** INSERT INTO ft2 (c1,c2,c3)
--- 2259,2284 ----
  (3 rows)
  
  INSERT INTO ft2 (c1,c2,c3) VALUES (1104,204,'ddd'), (1105,205,'eee');
+ EXPLAIN (verbose, costs off)
+ UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;              -- can be pushed down
+                                                       QUERY PLAN                                                      
+ ----------------------------------------------------------------------------------------------------------------------
+  Update on public.ft2
+    ->  Foreign Update on public.ft2
+          Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 300), c3 = (c3 || '_update3'::text) WHERE ((("C 1" % 10) = 3))
+ (3 rows)
+ 
  UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;
+ EXPLAIN (verbose, costs off)
+ UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;  -- can be pushed down
+                                                                             QUERY PLAN                                                                            
+ ------------------------------------------------------------------------------------------------------------------------------------------------------------------
+  Update on public.ft2
+    Output: c1, c2, c3, c4, c5, c6, c7, c8
+    ->  Foreign Update on public.ft2
+          Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 400), c3 = (c3 || '_update7'::text) WHERE ((("C 1" % 10) = 7)) RETURNING "C 1", c2, c3, c4, c5, c6, c7, c8
+ (4 rows)
+ 
  UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;
    c1  | c2  |         c3         |              c4              |            c5            | c6 |     c7     | c8  
  ------+-----+--------------------+------------------------------+--------------------------+----+------------+-----
***************
*** 2369,2375 **** UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING
  
  EXPLAIN (verbose, costs off)
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
!   FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
                                                                                                                                          QUERY PLAN                                                                                                                                        
  ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   Update on public.ft2
--- 2388,2394 ----
  
  EXPLAIN (verbose, costs off)
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
!   FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;                               -- can't be pushed down
                                                                                                                                          QUERY PLAN                                                                                                                                        
  ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   Update on public.ft2
***************
*** 2394,2409 **** UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
    FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
  EXPLAIN (verbose, costs off)
!   DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
!                                        QUERY PLAN                                       
! ----------------------------------------------------------------------------------------
   Delete on public.ft2
     Output: c1, c4
!    Remote SQL: DELETE FROM "S 1"."T 1" WHERE ctid = $1 RETURNING "C 1", c4
!    ->  Foreign Scan on public.ft2
!          Output: ctid
!          Remote SQL: SELECT ctid FROM "S 1"."T 1" WHERE ((("C 1" % 10) = 5)) FOR UPDATE
! (6 rows)
  
  DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
    c1  |              c4              
--- 2413,2426 ----
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
    FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
  EXPLAIN (verbose, costs off)
!   DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;                               -- can be pushed down
!                                          QUERY PLAN                                         
! --------------------------------------------------------------------------------------------
   Delete on public.ft2
     Output: c1, c4
!    ->  Foreign Delete on public.ft2
!          Remote SQL: DELETE FROM "S 1"."T 1" WHERE ((("C 1" % 10) = 5)) RETURNING "C 1", c4
! (4 rows)
  
  DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
    c1  |              c4              
***************
*** 2514,2520 **** DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
  (103 rows)
  
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;
                                                                                                                QUERY PLAN                                                                                                              
  --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   Delete on public.ft2
--- 2531,2537 ----
  (103 rows)
  
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;                -- can't be pushed down
                                                                                                                QUERY PLAN                                                                                                              
  --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
   Delete on public.ft2
***************
*** 3379,3394 **** INSERT INTO ft2 (c1,c2,c3) VALUES (9999,999,'foo') RETURNING tableoid::regclass;
  (1 row)
  
  EXPLAIN (verbose, costs off)
! UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
!                                                     QUERY PLAN                                                     
! -------------------------------------------------------------------------------------------------------------------
   Update on public.ft2
     Output: (tableoid)::regclass
!    Remote SQL: UPDATE "S 1"."T 1" SET c3 = $2 WHERE ctid = $1
!    ->  Foreign Scan on public.ft2
!          Output: c1, c2, NULL::integer, 'bar'::text, c4, c5, c6, c7, c8, ctid
!          Remote SQL: SELECT "C 1", c2, c4, c5, c6, c7, c8, ctid FROM "S 1"."T 1" WHERE (("C 1" = 9999)) FOR UPDATE
! (6 rows)
  
  UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
   tableoid 
--- 3396,3409 ----
  (1 row)
  
  EXPLAIN (verbose, costs off)
! UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;             -- can be pushed down
!                                      QUERY PLAN                                     
! ------------------------------------------------------------------------------------
   Update on public.ft2
     Output: (tableoid)::regclass
!    ->  Foreign Update on public.ft2
!          Remote SQL: UPDATE "S 1"."T 1" SET c3 = 'bar'::text WHERE (("C 1" = 9999))
! (4 rows)
  
  UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
   tableoid 
***************
*** 3397,3412 **** UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
  (1 row)
  
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;
!                                      QUERY PLAN                                     
! ------------------------------------------------------------------------------------
   Delete on public.ft2
     Output: (tableoid)::regclass
!    Remote SQL: DELETE FROM "S 1"."T 1" WHERE ctid = $1
!    ->  Foreign Scan on public.ft2
!          Output: ctid
!          Remote SQL: SELECT ctid FROM "S 1"."T 1" WHERE (("C 1" = 9999)) FOR UPDATE
! (6 rows)
  
  DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;
   tableoid 
--- 3412,3425 ----
  (1 row)
  
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;                       -- can be pushed down
!                              QUERY PLAN                             
! --------------------------------------------------------------------
   Delete on public.ft2
     Output: (tableoid)::regclass
!    ->  Foreign Delete on public.ft2
!          Remote SQL: DELETE FROM "S 1"."T 1" WHERE (("C 1" = 9999))
! (4 rows)
  
  DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;
   tableoid 
***************
*** 3560,3566 **** CONTEXT:  Remote SQL command: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6,
  UPDATE ft1 SET c2 = -c2 WHERE c1 = 1;  -- c2positive
  ERROR:  new row for relation "T 1" violates check constraint "c2positive"
  DETAIL:  Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1         , foo).
! CONTEXT:  Remote SQL command: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
  -- Test savepoint/rollback behavior
  select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
   c2  | count 
--- 3573,3579 ----
  UPDATE ft1 SET c2 = -c2 WHERE c1 = 1;  -- c2positive
  ERROR:  new row for relation "T 1" violates check constraint "c2positive"
  DETAIL:  Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1         , foo).
! CONTEXT:  Remote SQL command: UPDATE "S 1"."T 1" SET c2 = (- c2) WHERE (("C 1" = 1))
  -- Test savepoint/rollback behavior
  select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
   c2  | count 
***************
*** 3719,3725 **** savepoint s3;
  update ft2 set c2 = -2 where c2 = 42 and c1 = 10; -- fail on remote side
  ERROR:  new row for relation "T 1" violates check constraint "c2positive"
  DETAIL:  Failing row contains (10, -2, 00010_trig_update_trig_update, 1970-01-11 08:00:00+00, 1970-01-11 00:00:00, 0, 0         , foo).
! CONTEXT:  Remote SQL command: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
  rollback to savepoint s3;
  select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
   c2  | count 
--- 3732,3738 ----
  update ft2 set c2 = -2 where c2 = 42 and c1 = 10; -- fail on remote side
  ERROR:  new row for relation "T 1" violates check constraint "c2positive"
  DETAIL:  Failing row contains (10, -2, 00010_trig_update_trig_update, 1970-01-11 08:00:00+00, 1970-01-11 00:00:00, 0, 0         , foo).
! CONTEXT:  Remote SQL command: UPDATE "S 1"."T 1" SET c2 = (-2) WHERE ((c2 = 42)) AND (("C 1" = 10))
  rollback to savepoint s3;
  select c2, count(*) from ft2 where c2 < 500 group by 1 order by 1;
   c2  | count 
***************
*** 3939,3945 **** CONTEXT:  Remote SQL command: INSERT INTO "S 1"."T 1"("C 1", c2, c3, c4, c5, c6,
  UPDATE ft1 SET c2 = -c2 WHERE c1 = 1;  -- c2positive
  ERROR:  new row for relation "T 1" violates check constraint "c2positive"
  DETAIL:  Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1         , foo).
! CONTEXT:  Remote SQL command: UPDATE "S 1"."T 1" SET c2 = $2 WHERE ctid = $1
  ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2positive;
  -- But inconsistent check constraints provide inconsistent results
  ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2negative CHECK (c2 < 0);
--- 3952,3958 ----
  UPDATE ft1 SET c2 = -c2 WHERE c1 = 1;  -- c2positive
  ERROR:  new row for relation "T 1" violates check constraint "c2positive"
  DETAIL:  Failing row contains (1, -1, 00001_trig_update, 1970-01-02 08:00:00+00, 1970-01-02 00:00:00, 1, 1         , foo).
! CONTEXT:  Remote SQL command: UPDATE "S 1"."T 1" SET c2 = (- c2) WHERE (("C 1" = 1))
  ALTER FOREIGN TABLE ft1 DROP CONSTRAINT ft1_c2positive;
  -- But inconsistent check constraints provide inconsistent results
  ALTER FOREIGN TABLE ft1 ADD CONSTRAINT ft1_c2negative CHECK (c2 < 0);
***************
*** 4332,4337 **** NOTICE:  NEW: (13,"test triggered !")
--- 4345,4543 ----
   (0,27)
  (1 row)
  
+ -- cleanup
+ DROP TRIGGER trig_row_before ON rem1;
+ DROP TRIGGER trig_row_after ON rem1;
+ DROP TRIGGER trig_local_before ON loc1;
+ -- Test direct foreign table modification functionality
+ -- Test with statement-level triggers
+ CREATE TRIGGER trig_stmt_before
+ 	BEFORE DELETE OR INSERT OR UPDATE ON rem1
+ 	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+                         QUERY PLAN                        
+ ----------------------------------------------------------
+  Update on public.rem1
+    ->  Foreign Update on public.rem1
+          Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+ (3 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+                  QUERY PLAN                  
+ ---------------------------------------------
+  Delete on public.rem1
+    ->  Foreign Delete on public.rem1
+          Remote SQL: DELETE FROM public.loc1
+ (3 rows)
+ 
+ DROP TRIGGER trig_stmt_before ON rem1;
+ CREATE TRIGGER trig_stmt_after
+ 	AFTER DELETE OR INSERT OR UPDATE ON rem1
+ 	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+                         QUERY PLAN                        
+ ----------------------------------------------------------
+  Update on public.rem1
+    ->  Foreign Update on public.rem1
+          Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+ (3 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+                  QUERY PLAN                  
+ ---------------------------------------------
+  Delete on public.rem1
+    ->  Foreign Delete on public.rem1
+          Remote SQL: DELETE FROM public.loc1
+ (3 rows)
+ 
+ DROP TRIGGER trig_stmt_after ON rem1;
+ -- Test with row-level ON INSERT triggers
+ CREATE TRIGGER trig_row_before_insert
+ BEFORE INSERT ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+                         QUERY PLAN                        
+ ----------------------------------------------------------
+  Update on public.rem1
+    ->  Foreign Update on public.rem1
+          Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+ (3 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+                  QUERY PLAN                  
+ ---------------------------------------------
+  Delete on public.rem1
+    ->  Foreign Delete on public.rem1
+          Remote SQL: DELETE FROM public.loc1
+ (3 rows)
+ 
+ DROP TRIGGER trig_row_before_insert ON rem1;
+ CREATE TRIGGER trig_row_after_insert
+ AFTER INSERT ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+                         QUERY PLAN                        
+ ----------------------------------------------------------
+  Update on public.rem1
+    ->  Foreign Update on public.rem1
+          Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+ (3 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+                  QUERY PLAN                  
+ ---------------------------------------------
+  Delete on public.rem1
+    ->  Foreign Delete on public.rem1
+          Remote SQL: DELETE FROM public.loc1
+ (3 rows)
+ 
+ DROP TRIGGER trig_row_after_insert ON rem1;
+ -- Test with row-level ON UPDATE triggers
+ CREATE TRIGGER trig_row_before_update
+ BEFORE UPDATE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can't be pushed down
+                              QUERY PLAN                              
+ ---------------------------------------------------------------------
+  Update on public.rem1
+    Remote SQL: UPDATE public.loc1 SET f2 = $2 WHERE ctid = $1
+    ->  Foreign Scan on public.rem1
+          Output: f1, ''::text, ctid, rem1.*
+          Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+ (5 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+                  QUERY PLAN                  
+ ---------------------------------------------
+  Delete on public.rem1
+    ->  Foreign Delete on public.rem1
+          Remote SQL: DELETE FROM public.loc1
+ (3 rows)
+ 
+ DROP TRIGGER trig_row_before_update ON rem1;
+ CREATE TRIGGER trig_row_after_update
+ AFTER UPDATE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can't be pushed down
+                                   QUERY PLAN                                   
+ -------------------------------------------------------------------------------
+  Update on public.rem1
+    Remote SQL: UPDATE public.loc1 SET f2 = $2 WHERE ctid = $1 RETURNING f1, f2
+    ->  Foreign Scan on public.rem1
+          Output: f1, ''::text, ctid, rem1.*
+          Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+ (5 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+                  QUERY PLAN                  
+ ---------------------------------------------
+  Delete on public.rem1
+    ->  Foreign Delete on public.rem1
+          Remote SQL: DELETE FROM public.loc1
+ (3 rows)
+ 
+ DROP TRIGGER trig_row_after_update ON rem1;
+ -- Test with row-level ON DELETE triggers
+ CREATE TRIGGER trig_row_before_delete
+ BEFORE DELETE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+                         QUERY PLAN                        
+ ----------------------------------------------------------
+  Update on public.rem1
+    ->  Foreign Update on public.rem1
+          Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+ (3 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can't be pushed down
+                              QUERY PLAN                              
+ ---------------------------------------------------------------------
+  Delete on public.rem1
+    Remote SQL: DELETE FROM public.loc1 WHERE ctid = $1
+    ->  Foreign Scan on public.rem1
+          Output: ctid, rem1.*
+          Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+ (5 rows)
+ 
+ DROP TRIGGER trig_row_before_delete ON rem1;
+ CREATE TRIGGER trig_row_after_delete
+ AFTER DELETE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+                         QUERY PLAN                        
+ ----------------------------------------------------------
+  Update on public.rem1
+    ->  Foreign Update on public.rem1
+          Remote SQL: UPDATE public.loc1 SET f2 = ''::text
+ (3 rows)
+ 
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can't be pushed down
+                                QUERY PLAN                               
+ ------------------------------------------------------------------------
+  Delete on public.rem1
+    Remote SQL: DELETE FROM public.loc1 WHERE ctid = $1 RETURNING f1, f2
+    ->  Foreign Scan on public.rem1
+          Output: ctid, rem1.*
+          Remote SQL: SELECT f1, f2, ctid FROM public.loc1 FOR UPDATE
+ (5 rows)
+ 
+ DROP TRIGGER trig_row_after_delete ON rem1;
  -- ===================================================================
  -- test inheritance features
  -- ===================================================================
***************
*** 4801,4806 **** fetch from c;
--- 5007,5062 ----
  update bar set f2 = null where current of c;
  ERROR:  WHERE CURRENT OF is not supported for this table type
  rollback;
+ explain (verbose, costs off)
+ delete from foo where f1 < 5 returning *;
+                                    QUERY PLAN                                   
+ --------------------------------------------------------------------------------
+  Delete on public.foo
+    Output: foo.f1, foo.f2
+    Delete on public.foo
+    Foreign Delete on public.foo2
+    ->  Index Scan using i_foo_f1 on public.foo
+          Output: foo.ctid
+          Index Cond: (foo.f1 < 5)
+    ->  Foreign Delete on public.foo2
+          Remote SQL: DELETE FROM public.loct1 WHERE ((f1 < 5)) RETURNING f1, f2
+ (9 rows)
+ 
+ delete from foo where f1 < 5 returning *;
+  f1 | f2 
+ ----+----
+   1 |  1
+   3 |  3
+   0 |  0
+   2 |  2
+   4 |  4
+ (5 rows)
+ 
+ explain (verbose, costs off)
+ update bar set f2 = f2 + 100 returning *;
+                                   QUERY PLAN                                  
+ ------------------------------------------------------------------------------
+  Update on public.bar
+    Output: bar.f1, bar.f2
+    Update on public.bar
+    Foreign Update on public.bar2
+    ->  Seq Scan on public.bar
+          Output: bar.f1, (bar.f2 + 100), bar.ctid
+    ->  Foreign Update on public.bar2
+          Remote SQL: UPDATE public.loct2 SET f2 = (f2 + 100) RETURNING f1, f2
+ (8 rows)
+ 
+ update bar set f2 = f2 + 100 returning *;
+  f1 | f2  
+ ----+-----
+   1 | 311
+   2 | 322
+   6 | 266
+   3 | 333
+   4 | 344
+   7 | 277
+ (6 rows)
+ 
  drop table foo cascade;
  NOTICE:  drop cascades to foreign table foo2
  drop table bar cascade;
*** a/contrib/postgres_fdw/postgres_fdw.c
--- b/contrib/postgres_fdw/postgres_fdw.c
***************
*** 61,66 **** enum FdwScanPrivateIndex
--- 61,68 ----
  {
  	/* SQL statement to execute remotely (as a String node) */
  	FdwScanPrivateSelectSql,
+ 	/* List of restriction clauses that can be executed remotely */
+ 	FdwScanPrivateRemoteConds,
  	/* Integer list of attribute numbers retrieved by the SELECT */
  	FdwScanPrivateRetrievedAttrs,
  	/* Integer representing the desired fetch_size */
***************
*** 98,103 **** enum FdwModifyPrivateIndex
--- 100,126 ----
  };
  
  /*
+  * Similarly, this enum describes what's kept in the fdw_private list for
+  * a ForeignScan node that modifies a foreign table directly.  We store:
+  *
+  * 1) UPDATE/DELETE statement text to be sent to the remote server
+  * 2) Boolean flag showing if the remote query has a RETURNING clause
+  * 3) Integer list of attribute numbers retrieved by RETURNING, if any
+  * 4) Boolean flag showing if we set the command es_processed
+  */
+ enum FdwDirectModifyPrivateIndex
+ {
+ 	/* SQL statement to execute remotely (as a String node) */
+ 	FdwDirectModifyPrivateUpdateSql,
+ 	/* has-returning flag (as an integer Value node) */
+ 	FdwDirectModifyPrivateHasReturning,
+ 	/* Integer list of attribute numbers retrieved by RETURNING */
+ 	FdwDirectModifyPrivateRetrievedAttrs,
+ 	/* set-processed flag (as an integer Value node) */
+ 	FdwDirectModifyPrivateSetProcessed
+ };
+ 
+ /*
   * Execution state of a foreign scan using postgres_fdw.
   */
  typedef struct PgFdwScanState
***************
*** 164,169 **** typedef struct PgFdwModifyState
--- 187,222 ----
  } PgFdwModifyState;
  
  /*
+  * Execution state of a foreign scan that modifies a foreign table directly.
+  */
+ typedef struct PgFdwDirectModifyState
+ {
+ 	Relation	rel;			/* relcache entry for the foreign table */
+ 	AttInMetadata *attinmeta;	/* attribute datatype conversion metadata */
+ 
+ 	/* extracted fdw_private data */
+ 	char	   *query;			/* text of UPDATE/DELETE command */
+ 	bool		has_returning;	/* is there a RETURNING clause? */
+ 	List	   *retrieved_attrs;	/* attr numbers retrieved by RETURNING */
+ 	bool		set_processed;	/* do we set the command es_processed? */
+ 
+ 	/* for remote query execution */
+ 	PGconn	   *conn;			/* connection for the update */
+ 	int			numParams;		/* number of parameters passed to query */
+ 	FmgrInfo   *param_flinfo;	/* output conversion functions for them */
+ 	List	   *param_exprs;	/* executable expressions for param values */
+ 	const char **param_values;	/* textual values of query parameters */
+ 
+ 	/* for storing result tuples */
+ 	PGresult   *result;			/* result for query */
+ 	int			num_tuples;		/* # of result tuples */
+ 	int			next_tuple;		/* index of next one to return */
+ 
+ 	/* working memory context */
+ 	MemoryContext temp_cxt;		/* context for per-tuple temporary data */
+ } PgFdwDirectModifyState;
+ 
+ /*
   * Workspace for analyzing a foreign table.
   */
  typedef struct PgFdwAnalyzeState
***************
*** 263,268 **** static TupleTableSlot *postgresExecForeignDelete(EState *estate,
--- 316,328 ----
  static void postgresEndForeignModify(EState *estate,
  						 ResultRelInfo *resultRelInfo);
  static int	postgresIsForeignRelUpdatable(Relation rel);
+ static bool postgresPlanDirectModify(PlannerInfo *root,
+ 									 ModifyTable *plan,
+ 									 Index resultRelation,
+ 									 int subplan_index);
+ static void postgresBeginDirectModify(ForeignScanState *node, int eflags);
+ static TupleTableSlot *postgresIterateDirectModify(ForeignScanState *node);
+ static void postgresEndDirectModify(ForeignScanState *node);
  static void postgresExplainForeignScan(ForeignScanState *node,
  						   ExplainState *es);
  static void postgresExplainForeignModify(ModifyTableState *mtstate,
***************
*** 270,275 **** static void postgresExplainForeignModify(ModifyTableState *mtstate,
--- 330,337 ----
  							 List *fdw_private,
  							 int subplan_index,
  							 ExplainState *es);
+ static void postgresExplainDirectModify(ForeignScanState *node,
+ 										ExplainState *es);
  static bool postgresAnalyzeForeignTable(Relation relation,
  							AcquireSampleRowsFunc *func,
  							BlockNumber *totalpages);
***************
*** 311,316 **** static const char **convert_prep_stmt_params(PgFdwModifyState *fmstate,
--- 373,390 ----
  						 TupleTableSlot *slot);
  static void store_returning_result(PgFdwModifyState *fmstate,
  					   TupleTableSlot *slot, PGresult *res);
+ static void execute_dml_stmt(ForeignScanState *node);
+ static TupleTableSlot *get_returning_data(ForeignScanState *node);
+ static void prepare_query_params(PlanState *node,
+ 					 List *fdw_exprs,
+ 					 int numParams,
+ 					 FmgrInfo **param_flinfo,
+ 					 List **param_exprs,
+ 					 const char ***param_values);
+ static void process_query_params(ExprContext *econtext,
+ 					 FmgrInfo *param_flinfo,
+ 					 List *param_exprs,
+ 					 const char **param_values);
  static int postgresAcquireSampleRowsFunc(Relation relation, int elevel,
  							  HeapTuple *rows, int targrows,
  							  double *totalrows,
***************
*** 362,373 **** postgres_fdw_handler(PG_FUNCTION_ARGS)
--- 436,452 ----
  	routine->ExecForeignDelete = postgresExecForeignDelete;
  	routine->EndForeignModify = postgresEndForeignModify;
  	routine->IsForeignRelUpdatable = postgresIsForeignRelUpdatable;
+ 	routine->PlanDirectModify = postgresPlanDirectModify;
+ 	routine->BeginDirectModify = postgresBeginDirectModify;
+ 	routine->IterateDirectModify = postgresIterateDirectModify;
+ 	routine->EndDirectModify = postgresEndDirectModify;
  
  	/* Function for EvalPlanQual rechecks */
  	routine->RecheckForeignScan = postgresRecheckForeignScan;
  	/* Support functions for EXPLAIN */
  	routine->ExplainForeignScan = postgresExplainForeignScan;
  	routine->ExplainForeignModify = postgresExplainForeignModify;
+ 	routine->ExplainDirectModify = postgresExplainDirectModify;
  
  	/* Support functions for ANALYZE */
  	routine->AnalyzeForeignTable = postgresAnalyzeForeignTable;
***************
*** 1122,1128 **** postgresGetForeignPlan(PlannerInfo *root,
  	 * Build the fdw_private list that will be available to the executor.
  	 * Items in the list must match order in enum FdwScanPrivateIndex.
  	 */
! 	fdw_private = list_make4(makeString(sql.data),
  							 retrieved_attrs,
  							 makeInteger(fpinfo->fetch_size),
  							 makeInteger(foreignrel->umid));
--- 1201,1208 ----
  	 * Build the fdw_private list that will be available to the executor.
  	 * Items in the list must match order in enum FdwScanPrivateIndex.
  	 */
! 	fdw_private = list_make5(makeString(sql.data),
! 							 remote_conds,
  							 retrieved_attrs,
  							 makeInteger(fpinfo->fetch_size),
  							 makeInteger(foreignrel->umid));
***************
*** 1159,1166 **** postgresBeginForeignScan(ForeignScanState *node, int eflags)
  	PgFdwScanState *fsstate;
  	UserMapping *user;
  	int			numParams;
- 	int			i;
- 	ListCell   *lc;
  
  	/*
  	 * Do nothing in EXPLAIN (no ANALYZE) case.  node->fdw_state stays NULL.
--- 1239,1244 ----
***************
*** 1247,1288 **** postgresBeginForeignScan(ForeignScanState *node, int eflags)
  
  	fsstate->attinmeta = TupleDescGetAttInMetadata(fsstate->tupdesc);
  
- 	/* Prepare for output conversion of parameters used in remote query. */
- 	numParams = list_length(fsplan->fdw_exprs);
- 	fsstate->numParams = numParams;
- 	fsstate->param_flinfo = (FmgrInfo *) palloc0(sizeof(FmgrInfo) * numParams);
- 
- 	i = 0;
- 	foreach(lc, fsplan->fdw_exprs)
- 	{
- 		Node	   *param_expr = (Node *) lfirst(lc);
- 		Oid			typefnoid;
- 		bool		isvarlena;
- 
- 		getTypeOutputInfo(exprType(param_expr), &typefnoid, &isvarlena);
- 		fmgr_info(typefnoid, &fsstate->param_flinfo[i]);
- 		i++;
- 	}
- 
  	/*
! 	 * Prepare remote-parameter expressions for evaluation.  (Note: in
! 	 * practice, we expect that all these expressions will be just Params, so
! 	 * we could possibly do something more efficient than using the full
! 	 * expression-eval machinery for this.  But probably there would be little
! 	 * benefit, and it'd require postgres_fdw to know more than is desirable
! 	 * about Param evaluation.)
! 	 */
! 	fsstate->param_exprs = (List *)
! 		ExecInitExpr((Expr *) fsplan->fdw_exprs,
! 					 (PlanState *) node);
! 
! 	/*
! 	 * Allocate buffer for text form of query parameters, if any.
  	 */
  	if (numParams > 0)
! 		fsstate->param_values = (const char **) palloc0(numParams * sizeof(char *));
! 	else
! 		fsstate->param_values = NULL;
  }
  
  /*
--- 1325,1342 ----
  
  	fsstate->attinmeta = TupleDescGetAttInMetadata(fsstate->tupdesc);
  
  	/*
! 	 * Prepare for processing of parameters used in remote query, if any.
  	 */
+ 	numParams = list_length(fsplan->fdw_exprs);
+ 	fsstate->numParams = numParams;
  	if (numParams > 0)
! 		prepare_query_params((PlanState *) node,
! 							 fsplan->fdw_exprs,
! 							 numParams,
! 							 &fsstate->param_flinfo,
! 							 &fsstate->param_exprs,
! 							 &fsstate->param_values);
  }
  
  /*
***************
*** 1447,1459 **** postgresAddForeignUpdateTargets(Query *parsetree,
  /*
   * postgresPlanForeignModify
   *		Plan an insert/update/delete operation on a foreign table
-  *
-  * Note: currently, the plan tree generated for UPDATE/DELETE will always
-  * include a ForeignScan that retrieves ctids (using SELECT FOR UPDATE)
-  * and then the ModifyTable node will have to execute individual remote
-  * UPDATE/DELETE commands.  If there are no local conditions or joins
-  * needed, it'd be better to let the scan node do UPDATE/DELETE RETURNING
-  * and then do nothing at ModifyTable.  Room for future optimization ...
   */
  static List *
  postgresPlanForeignModify(PlannerInfo *root,
--- 1501,1506 ----
***************
*** 1992,1997 **** postgresRecheckForeignScan(ForeignScanState *node, TupleTableSlot *slot)
--- 2039,2352 ----
  }
  
  /*
+  * postgresPlanDirectModify
+  *		Consider a direct foreign table modification
+  *
+  * Decide whether it is safe to modify a foreign table directly,  and if so,
+  * rewrite subplan accordingly.
+  */
+ static bool
+ postgresPlanDirectModify(PlannerInfo *root,
+ 						 ModifyTable *plan,
+ 						 Index resultRelation,
+ 						 int subplan_index)
+ {
+ 	CmdType		operation = plan->operation;
+ 	Plan	   *subplan = (Plan *) list_nth(plan->plans, subplan_index);
+ 	RangeTblEntry *rte = planner_rt_fetch(resultRelation, root);
+ 	Relation	rel;
+ 	StringInfoData sql;
+ 	ForeignScan *fscan;
+ 	List	   *targetAttrs = NIL;
+ 	List	   *remote_conds;
+ 	List	   *params_list = NIL;
+ 	List	   *returningList = NIL;
+ 	List	   *retrieved_attrs = NIL;
+ 
+ 	/*
+ 	 * Decide whether it is safe to modify a foreign table directly.
+ 	 */
+ 
+ 	/*
+ 	 * The table modification must be an UPDATE or DELETE.
+ 	 */
+ 	if (operation != CMD_UPDATE && operation != CMD_DELETE)
+ 		return false;
+ 
+ 	/*
+ 	 * It's unsafe to modify a foreign table directly if there are any local
+ 	 * joins needed.
+ 	 */
+ 	if (!IsA(subplan, ForeignScan))
+ 		return false;
+ 
+ 	/*
+ 	 * It's unsafe to modify a foreign table directly if there are any quals
+ 	 * that should be evaluated locally.
+ 	 */
+ 	if (subplan->qual != NIL)
+ 		return false;
+ 
+ 	/*
+ 	 * We can't handle an UPDATE or DELETE on a foreign join for now.
+ 	 */
+ 	fscan = (ForeignScan *) subplan;
+ 	if (fscan->scan.scanrelid == 0)
+ 		return false;
+ 
+ 	/*
+ 	 * It's unsafe to update a foreign table directly, if any expressions to
+ 	 * assign to the target columns are unsafe to evaluate remotely.
+ 	 */
+ 	if (operation == CMD_UPDATE)
+ 	{
+ 		RelOptInfo *baserel = root->simple_rel_array[resultRelation];
+ 		int			col;
+ 
+ 		/*
+ 		 * We transmit only columns that were explicitly targets of the UPDATE,
+ 		 * so as to avoid unnecessary data transmission.
+ 		 */
+ 		col = -1;
+ 		while ((col = bms_next_member(rte->updatedCols, col)) >= 0)
+ 		{
+ 			/* bit numbers are offset by FirstLowInvalidHeapAttributeNumber */
+ 			AttrNumber	attno = col + FirstLowInvalidHeapAttributeNumber;
+ 			TargetEntry *tle;
+ 
+ 			if (attno <= InvalidAttrNumber)		/* shouldn't happen */
+ 				elog(ERROR, "system-column update is not supported");
+ 
+ 			tle = get_tle_by_resno(subplan->targetlist, attno);
+ 
+ 			if (!is_foreign_expr(root, baserel, (Expr *) tle->expr))
+ 				return false;
+ 
+ 			targetAttrs = lappend_int(targetAttrs, attno);
+ 		}
+ 	}
+ 
+ 	/*
+ 	 * Ok, rewrite subplan so as to modify the foreign table directly.
+ 	 */
+ 	initStringInfo(&sql);
+ 
+ 	/*
+ 	 * Core code already has some lock on each rel being planned, so we can
+ 	 * use NoLock here.
+ 	 */
+ 	rel = heap_open(rte->relid, NoLock);
+ 
+ 	/*
+ 	 * Extract the baserestrictinfo clauses that can be evaluated remotely.
+ 	 */
+ 	remote_conds = (List *) list_nth(fscan->fdw_private,
+ 									 FdwScanPrivateRemoteConds);
+ 
+ 	/*
+ 	 * Extract the relevant RETURNING list if any.
+ 	 */
+ 	if (plan->returningLists)
+ 		returningList = (List *) list_nth(plan->returningLists, subplan_index);
+ 
+ 	/*
+ 	 * Construct the SQL command string.
+ 	 */
+ 	switch (operation)
+ 	{
+ 		case CMD_UPDATE:
+ 			deparseDirectUpdateSql(&sql, root, resultRelation, rel,
+ 								   ((Plan *) fscan)->targetlist,
+ 								   targetAttrs,
+ 								   remote_conds, &params_list,
+ 								   returningList, &retrieved_attrs);
+ 			break;
+ 		case CMD_DELETE:
+ 			deparseDirectDeleteSql(&sql, root, resultRelation, rel,
+ 								   remote_conds, &params_list,
+ 								   returningList, &retrieved_attrs);
+ 			break;
+ 		default:
+ 			elog(ERROR, "unexpected operation: %d", (int) operation);
+ 			break;
+ 	}
+ 
+ 	/*
+ 	 * Update the operation info.
+ 	 */
+ 	fscan->operation = operation;
+ 
+ 	/*
+ 	 * Update the fdw_exprs list that will be available to the executor.
+ 	 */
+ 	fscan->fdw_exprs = params_list;
+ 
+ 	/*
+ 	 * Update the fdw_private list that will be available to the executor.
+ 	 * Items in the list must match enum FdwDirectModifyPrivateIndex, above.
+ 	 */
+ 	fscan->fdw_private = list_make4(makeString(sql.data),
+ 									makeInteger((retrieved_attrs != NIL)),
+ 									retrieved_attrs,
+ 									makeInteger(plan->canSetTag));
+ 
+ 	heap_close(rel, NoLock);
+ 	return true;
+ }
+ 
+ /*
+  * postgresBeginDirectModify
+  *		Prepare a direct foreign table modification
+  */
+ static void
+ postgresBeginDirectModify(ForeignScanState *node, int eflags)
+ {
+ 	ForeignScan *fsplan = (ForeignScan *) node->ss.ps.plan;
+ 	EState	   *estate = node->ss.ps.state;
+ 	PgFdwDirectModifyState *dmstate;
+ 	RangeTblEntry *rte;
+ 	Oid			userid;
+ 	ForeignTable *table;
+ 	UserMapping *user;
+ 	int			numParams;
+ 
+ 	/*
+ 	 * Do nothing in EXPLAIN (no ANALYZE) case.  node->fdw_state stays NULL.
+ 	 */
+ 	if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
+ 		return;
+ 
+ 	/*
+ 	 * We'll save private state in node->fdw_state.
+ 	 */
+ 	dmstate = (PgFdwDirectModifyState *) palloc0(sizeof(PgFdwDirectModifyState));
+ 	node->fdw_state = (void *) dmstate;
+ 
+ 	/*
+ 	 * Identify which user to do the remote access as.  This should match what
+ 	 * ExecCheckRTEPerms() does.
+ 	 */
+ 	rte = rt_fetch(fsplan->scan.scanrelid, estate->es_range_table);
+ 	userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
+ 
+ 	/* Get info about foreign table. */
+ 	dmstate->rel = node->ss.ss_currentRelation;
+ 	table = GetForeignTable(RelationGetRelid(dmstate->rel));
+ 	user = GetUserMapping(userid, table->serverid);
+ 
+ 	/*
+ 	 * Get connection to the foreign server.  Connection manager will
+ 	 * establish new connection if necessary.
+ 	 */
+ 	dmstate->conn = GetConnection(user, false);
+ 
+ 	/* Initialize state variable */
+ 	dmstate->num_tuples = -1;		/* -1 means not set yet */
+ 
+ 	/* Get private info created by planner functions. */
+ 	dmstate->query = strVal(list_nth(fsplan->fdw_private,
+ 									 FdwDirectModifyPrivateUpdateSql));
+ 	dmstate->has_returning = intVal(list_nth(fsplan->fdw_private,
+ 										 FdwDirectModifyPrivateHasReturning));
+ 	dmstate->retrieved_attrs = (List *) list_nth(fsplan->fdw_private,
+ 										FdwDirectModifyPrivateRetrievedAttrs);
+ 	dmstate->set_processed = intVal(list_nth(fsplan->fdw_private,
+ 										 FdwDirectModifyPrivateSetProcessed));
+ 
+ 	/* Create context for per-tuple temp workspace. */
+ 	dmstate->temp_cxt = AllocSetContextCreate(estate->es_query_cxt,
+ 											  "postgres_fdw temporary data",
+ 											  ALLOCSET_SMALL_MINSIZE,
+ 											  ALLOCSET_SMALL_INITSIZE,
+ 											  ALLOCSET_SMALL_MAXSIZE);
+ 
+ 	/* Prepare for input conversion of RETURNING results. */
+ 	if (dmstate->has_returning)
+ 		dmstate->attinmeta = TupleDescGetAttInMetadata(RelationGetDescr(dmstate->rel));
+ 
+ 	/*
+ 	 * Prepare for processing of parameters used in remote query, if any.
+ 	 */
+ 	numParams = list_length(fsplan->fdw_exprs);
+ 	dmstate->numParams = numParams;
+ 	if (numParams > 0)
+ 		prepare_query_params((PlanState *) node,
+ 							 fsplan->fdw_exprs,
+ 							 numParams,
+ 							 &dmstate->param_flinfo,
+ 							 &dmstate->param_exprs,
+ 							 &dmstate->param_values);
+ }
+ 
+ /*
+  * postgresIterateDirectModify
+  *		Execute a direct foreign table modification
+  */
+ static TupleTableSlot *
+ postgresIterateDirectModify(ForeignScanState *node)
+ {
+ 	PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
+ 	EState	   *estate = node->ss.ps.state;
+ 	ResultRelInfo *resultRelInfo = estate->es_result_relation_info;
+ 
+ 	/*
+ 	 * If this is the first call after Begin, execute the statement.
+ 	 */
+ 	if (dmstate->num_tuples == -1)
+ 		execute_dml_stmt(node);
+ 
+ 	/*
+ 	 * If the local query doesn't specify RETURNING, just clear tuple slot.
+ 	 */
+ 	if (!resultRelInfo->ri_projectReturning)
+ 	{
+ 		TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
+ 		Instrumentation *instr = node->ss.ps.instrument;
+ 
+ 		Assert(!dmstate->has_returning);
+ 
+ 		/* Increment the command es_processed count if necessary. */
+ 		if (dmstate->set_processed)
+ 			estate->es_processed += dmstate->num_tuples;
+ 
+ 		/* Increment the tuple count for EXPLAIN ANALYZE if necessary. */
+ 		if (instr)
+ 			instr->tuplecount += dmstate->num_tuples;
+ 
+ 		return ExecClearTuple(slot);
+ 	}
+ 
+ 	/*
+ 	 * Get the next RETURNING tuple.
+ 	 */
+ 	return get_returning_data(node);
+ }
+ 
+ /*
+  * postgresEndDirectModify
+  *		Finish a direct foreign table modification
+  */
+ static void
+ postgresEndDirectModify(ForeignScanState *node)
+ {
+ 	PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
+ 
+ 	/* if dmstate is NULL, we are in EXPLAIN; nothing to do */
+ 	if (dmstate == NULL)
+ 		return;
+ 
+ 	/* Release PGresult */
+ 	if (dmstate->result)
+ 		PQclear(dmstate->result);
+ 
+ 	/* Release remote connection */
+ 	ReleaseConnection(dmstate->conn);
+ 	dmstate->conn = NULL;
+ 
+ 	/* MemoryContext will be deleted automatically. */
+ }
+ 
+ /*
   * postgresExplainForeignScan
   *		Produce extra output for EXPLAIN of a ForeignScan on a foreign table
   */
***************
*** 2044,2049 **** postgresExplainForeignModify(ModifyTableState *mtstate,
--- 2399,2423 ----
  	}
  }
  
+ /*
+  * postgresExplainDirectModify
+  *		Produce extra output for EXPLAIN of a ForeignScan that modifies a
+  *		foreign table directly
+  */
+ static void
+ postgresExplainDirectModify(ForeignScanState *node, ExplainState *es)
+ {
+ 	List	   *fdw_private;
+ 	char	   *sql;
+ 
+ 	if (es->verbose)
+ 	{
+ 		fdw_private = ((ForeignScan *) node->ss.ps.plan)->fdw_private;
+ 		sql = strVal(list_nth(fdw_private, FdwDirectModifyPrivateUpdateSql));
+ 		ExplainPropertyText("Remote SQL", sql, es);
+ 	}
+ }
+ 
  
  /*
   * estimate_path_cost_size
***************
*** 2419,2456 **** create_cursor(ForeignScanState *node)
  	 */
  	if (numParams > 0)
  	{
- 		int			nestlevel;
  		MemoryContext oldcontext;
- 		int			i;
- 		ListCell   *lc;
  
  		oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
  
! 		nestlevel = set_transmission_modes();
! 
! 		i = 0;
! 		foreach(lc, fsstate->param_exprs)
! 		{
! 			ExprState  *expr_state = (ExprState *) lfirst(lc);
! 			Datum		expr_value;
! 			bool		isNull;
! 
! 			/* Evaluate the parameter expression */
! 			expr_value = ExecEvalExpr(expr_state, econtext, &isNull, NULL);
! 
! 			/*
! 			 * Get string representation of each parameter value by invoking
! 			 * type-specific output function, unless the value is null.
! 			 */
! 			if (isNull)
! 				values[i] = NULL;
! 			else
! 				values[i] = OutputFunctionCall(&fsstate->param_flinfo[i],
! 											   expr_value);
! 			i++;
! 		}
! 
! 		reset_transmission_modes(nestlevel);
  
  		MemoryContextSwitchTo(oldcontext);
  	}
--- 2793,2806 ----
  	 */
  	if (numParams > 0)
  	{
  		MemoryContext oldcontext;
  
  		oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
  
! 		process_query_params(econtext,
! 							 fsstate->param_flinfo,
! 							 fsstate->param_exprs,
! 							 values);
  
  		MemoryContextSwitchTo(oldcontext);
  	}
***************
*** 2771,2776 **** store_returning_result(PgFdwModifyState *fmstate,
--- 3121,3317 ----
  }
  
  /*
+  * Execute a direct UPDATE/DELETE statement.
+  */
+ static void
+ execute_dml_stmt(ForeignScanState *node)
+ {
+ 	PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
+ 	ExprContext *econtext = node->ss.ps.ps_ExprContext;
+ 	int			numParams = dmstate->numParams;
+ 	const char **values = dmstate->param_values;
+ 
+ 	/*
+ 	 * Construct array of query parameter values in text format.
+ 	 */
+ 	if (numParams > 0)
+ 		process_query_params(econtext,
+ 							 dmstate->param_flinfo,
+ 							 dmstate->param_exprs,
+ 							 values);
+ 
+ 	/*
+ 	 * Notice that we pass NULL for paramTypes, thus forcing the remote server
+ 	 * to infer types for all parameters.  Since we explicitly cast every
+ 	 * parameter (see deparse.c), the "inference" is trivial and will produce
+ 	 * the desired result.  This allows us to avoid assuming that the remote
+ 	 * server has the same OIDs we do for the parameters' types.
+ 	 *
+ 	 * We don't use a PG_TRY block here, so be careful not to throw error
+ 	 * without releasing the PGresult.
+ 	 */
+ 	dmstate->result = PQexecParams(dmstate->conn, dmstate->query,
+ 								   numParams, NULL, values, NULL, NULL, 0);
+ 	if (PQresultStatus(dmstate->result) !=
+ 		(dmstate->has_returning ? PGRES_TUPLES_OK : PGRES_COMMAND_OK))
+ 		pgfdw_report_error(ERROR, dmstate->result, dmstate->conn, true,
+ 						   dmstate->query);
+ 
+ 	/* Get the number of rows affected. */
+ 	if (dmstate->has_returning)
+ 		dmstate->num_tuples = PQntuples(dmstate->result);
+ 	else
+ 		dmstate->num_tuples = atoi(PQcmdTuples(dmstate->result));
+ }
+ 
+ /*
+  * Get the result of a RETURNING clause.
+  */
+ static TupleTableSlot *
+ get_returning_data(ForeignScanState *node)
+ {
+ 	PgFdwDirectModifyState *dmstate = (PgFdwDirectModifyState *) node->fdw_state;
+ 	EState	   *estate = node->ss.ps.state;
+ 	ResultRelInfo *resultRelInfo = estate->es_result_relation_info;
+ 	TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
+ 
+ 	Assert(resultRelInfo->ri_projectReturning);
+ 
+ 	/* If we didn't get any tuples, must be end of data. */
+ 	if (dmstate->next_tuple >= dmstate->num_tuples)
+ 		return ExecClearTuple(slot);
+ 
+ 	/* Increment the command es_processed count if necessary. */
+ 	if (dmstate->set_processed)
+ 		estate->es_processed += 1;
+ 
+ 	/*
+ 	 * Store a RETURNING tuple.  If has_returning is false, just emit a dummy
+ 	 * tuple.  (has_returning is false when the local query is of the form
+ 	 * "UPDATE/DELETE .. RETURNING 1" for example.)
+ 	 */
+ 	if (!dmstate->has_returning)
+ 		ExecStoreAllNullTuple(slot);
+ 	else
+ 	{
+ 		/*
+ 		 * On error, be sure to release the PGresult on the way out.  Callers
+ 		 * do not have PG_TRY blocks to ensure this happens.
+ 		 */
+ 		PG_TRY();
+ 		{
+ 			HeapTuple	newtup;
+ 
+ 			newtup = make_tuple_from_result_row(dmstate->result,
+ 												dmstate->next_tuple,
+ 												dmstate->rel,
+ 												dmstate->attinmeta,
+ 												dmstate->retrieved_attrs,
+ 												NULL,
+ 												dmstate->temp_cxt);
+ 			ExecStoreTuple(newtup, slot, InvalidBuffer, false);
+ 		}
+ 		PG_CATCH();
+ 		{
+ 			if (dmstate->result)
+ 				PQclear(dmstate->result);
+ 			PG_RE_THROW();
+ 		}
+ 		PG_END_TRY();
+ 	}
+ 	dmstate->next_tuple++;
+ 
+ 	/* Make slot available for evaluation of the local query RETURNING list. */
+ 	resultRelInfo->ri_projectReturning->pi_exprContext->ecxt_scantuple = slot;
+ 
+ 	return slot;
+ }
+ 
+ /*
+  * Prepare for processing of parameters used in remote query.
+  */
+ static void
+ prepare_query_params(PlanState *node,
+ 					 List *fdw_exprs,
+ 					 int numParams,
+ 					 FmgrInfo **param_flinfo,
+ 					 List **param_exprs,
+ 					 const char ***param_values)
+ {
+ 	int			i;
+ 	ListCell   *lc;
+ 
+ 	Assert(numParams > 0);
+ 
+ 	/* Prepare for output conversion of parameters used in remote query. */
+ 	*param_flinfo = (FmgrInfo *) palloc0(sizeof(FmgrInfo) * numParams);
+ 
+ 	i = 0;
+ 	foreach(lc, fdw_exprs)
+ 	{
+ 		Node	   *param_expr = (Node *) lfirst(lc);
+ 		Oid			typefnoid;
+ 		bool		isvarlena;
+ 
+ 		getTypeOutputInfo(exprType(param_expr), &typefnoid, &isvarlena);
+ 		fmgr_info(typefnoid, &(*param_flinfo)[i]);
+ 		i++;
+ 	}
+ 
+ 	/*
+ 	 * Prepare remote-parameter expressions for evaluation.  (Note: in
+ 	 * practice, we expect that all these expressions will be just Params, so
+ 	 * we could possibly do something more efficient than using the full
+ 	 * expression-eval machinery for this.  But probably there would be little
+ 	 * benefit, and it'd require postgres_fdw to know more than is desirable
+ 	 * about Param evaluation.)
+ 	 */
+ 	*param_exprs = (List *) ExecInitExpr((Expr *) fdw_exprs, node);
+ 
+ 	/* Allocate buffer for text form of query parameters. */
+ 	*param_values = (const char **) palloc0(numParams * sizeof(char *));
+ }
+ 
+ /*
+  * Construct array of query parameter values in text format.
+  */
+ static void
+ process_query_params(ExprContext *econtext,
+ 					 FmgrInfo *param_flinfo,
+ 					 List *param_exprs,
+ 					 const char **param_values)
+ {
+ 	int			nestlevel;
+ 	int			i;
+ 	ListCell   *lc;
+ 
+ 	nestlevel = set_transmission_modes();
+ 
+ 	i = 0;
+ 	foreach(lc, param_exprs)
+ 	{
+ 		ExprState  *expr_state = (ExprState *) lfirst(lc);
+ 		Datum		expr_value;
+ 		bool		isNull;
+ 
+ 		/* Evaluate the parameter expression */
+ 		expr_value = ExecEvalExpr(expr_state, econtext, &isNull, NULL);
+ 
+ 		/*
+ 		 * Get string representation of each parameter value by invoking
+ 		 * type-specific output function, unless the value is null.
+ 		 */
+ 		if (isNull)
+ 			param_values[i] = NULL;
+ 		else
+ 			param_values[i] = OutputFunctionCall(&param_flinfo[i], expr_value);
+ 			i++;
+ 	}
+ 
+ 	reset_transmission_modes(nestlevel);
+ }
+ 
+ /*
   * postgresAnalyzeForeignTable
   *		Test whether analyzing this foreign table is supported
   */
*** a/contrib/postgres_fdw/postgres_fdw.h
--- b/contrib/postgres_fdw/postgres_fdw.h
***************
*** 130,139 **** extern void deparseUpdateSql(StringInfo buf, PlannerInfo *root,
--- 130,153 ----
  				 Index rtindex, Relation rel,
  				 List *targetAttrs, List *returningList,
  				 List **retrieved_attrs);
+ extern void deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
+ 								   Index rtindex, Relation rel,
+ 								   List *targetlist,
+ 								   List *targetAttrs,
+ 								   List *remote_conds,
+ 								   List **params_list,
+ 								   List *returningList,
+ 								   List **retrieved_attrs);
  extern void deparseDeleteSql(StringInfo buf, PlannerInfo *root,
  				 Index rtindex, Relation rel,
  				 List *returningList,
  				 List **retrieved_attrs);
+ extern void deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
+ 								   Index rtindex, Relation rel,
+ 								   List *remote_conds,
+ 								   List **params_list,
+ 								   List *returningList,
+ 								   List **retrieved_attrs);
  extern void deparseAnalyzeSizeSql(StringInfo buf, Relation rel);
  extern void deparseAnalyzeSql(StringInfo buf, Relation rel,
  				  List **retrieved_attrs);
*** a/contrib/postgres_fdw/sql/postgres_fdw.sql
--- b/contrib/postgres_fdw/sql/postgres_fdw.sql
***************
*** 604,631 **** INSERT INTO ft2 (c1,c2,c3) SELECT c1+1000,c2+100, c3 || c3 FROM ft2 LIMIT 20;
  INSERT INTO ft2 (c1,c2,c3)
    VALUES (1101,201,'aaa'), (1102,202,'bbb'), (1103,203,'ccc') RETURNING *;
  INSERT INTO ft2 (c1,c2,c3) VALUES (1104,204,'ddd'), (1105,205,'eee');
  UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;
  UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;
  EXPLAIN (verbose, costs off)
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
!   FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
    FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
  EXPLAIN (verbose, costs off)
!   DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
  DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;
  DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;
  SELECT c1,c2,c3,c4 FROM ft2 ORDER BY c1;
  EXPLAIN (verbose, costs off)
  INSERT INTO ft2 (c1,c2,c3) VALUES (9999,999,'foo') RETURNING tableoid::regclass;
  INSERT INTO ft2 (c1,c2,c3) VALUES (9999,999,'foo') RETURNING tableoid::regclass;
  EXPLAIN (verbose, costs off)
! UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
  UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;
  DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;
  
  -- Test that trigger on remote table works as expected
--- 604,635 ----
  INSERT INTO ft2 (c1,c2,c3)
    VALUES (1101,201,'aaa'), (1102,202,'bbb'), (1103,203,'ccc') RETURNING *;
  INSERT INTO ft2 (c1,c2,c3) VALUES (1104,204,'ddd'), (1105,205,'eee');
+ EXPLAIN (verbose, costs off)
+ UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;              -- can be pushed down
  UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;
+ EXPLAIN (verbose, costs off)
+ UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;  -- can be pushed down
  UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;
  EXPLAIN (verbose, costs off)
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
!   FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;                               -- can't be pushed down
  UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
    FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9;
  EXPLAIN (verbose, costs off)
!   DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;                               -- can be pushed down
  DELETE FROM ft2 WHERE c1 % 10 = 5 RETURNING c1, c4;
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;                -- can't be pushed down
  DELETE FROM ft2 USING ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 2;
  SELECT c1,c2,c3,c4 FROM ft2 ORDER BY c1;
  EXPLAIN (verbose, costs off)
  INSERT INTO ft2 (c1,c2,c3) VALUES (9999,999,'foo') RETURNING tableoid::regclass;
  INSERT INTO ft2 (c1,c2,c3) VALUES (9999,999,'foo') RETURNING tableoid::regclass;
  EXPLAIN (verbose, costs off)
! UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;             -- can be pushed down
  UPDATE ft2 SET c3 = 'bar' WHERE c1 = 9999 RETURNING tableoid::regclass;
  EXPLAIN (verbose, costs off)
! DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;                       -- can be pushed down
  DELETE FROM ft2 WHERE c1 = 9999 RETURNING tableoid::regclass;
  
  -- Test that trigger on remote table works as expected
***************
*** 954,959 **** UPDATE rem1 SET f2 = 'testo';
--- 958,1047 ----
  -- Test returning a system attribute
  INSERT INTO rem1(f2) VALUES ('test') RETURNING ctid;
  
+ -- cleanup
+ DROP TRIGGER trig_row_before ON rem1;
+ DROP TRIGGER trig_row_after ON rem1;
+ DROP TRIGGER trig_local_before ON loc1;
+ 
+ 
+ -- Test direct foreign table modification functionality
+ 
+ -- Test with statement-level triggers
+ CREATE TRIGGER trig_stmt_before
+ 	BEFORE DELETE OR INSERT OR UPDATE ON rem1
+ 	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+ DROP TRIGGER trig_stmt_before ON rem1;
+ 
+ CREATE TRIGGER trig_stmt_after
+ 	AFTER DELETE OR INSERT OR UPDATE ON rem1
+ 	FOR EACH STATEMENT EXECUTE PROCEDURE trigger_func();
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+ DROP TRIGGER trig_stmt_after ON rem1;
+ 
+ -- Test with row-level ON INSERT triggers
+ CREATE TRIGGER trig_row_before_insert
+ BEFORE INSERT ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+ DROP TRIGGER trig_row_before_insert ON rem1;
+ 
+ CREATE TRIGGER trig_row_after_insert
+ AFTER INSERT ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+ DROP TRIGGER trig_row_after_insert ON rem1;
+ 
+ -- Test with row-level ON UPDATE triggers
+ CREATE TRIGGER trig_row_before_update
+ BEFORE UPDATE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can't be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+ DROP TRIGGER trig_row_before_update ON rem1;
+ 
+ CREATE TRIGGER trig_row_after_update
+ AFTER UPDATE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can't be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can be pushed down
+ DROP TRIGGER trig_row_after_update ON rem1;
+ 
+ -- Test with row-level ON DELETE triggers
+ CREATE TRIGGER trig_row_before_delete
+ BEFORE DELETE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can't be pushed down
+ DROP TRIGGER trig_row_before_delete ON rem1;
+ 
+ CREATE TRIGGER trig_row_after_delete
+ AFTER DELETE ON rem1
+ FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
+ EXPLAIN (verbose, costs off)
+ UPDATE rem1 set f2 = '';          -- can be pushed down
+ EXPLAIN (verbose, costs off)
+ DELETE FROM rem1;                 -- can't be pushed down
+ DROP TRIGGER trig_row_after_delete ON rem1;
+ 
  -- ===================================================================
  -- test inheritance features
  -- ===================================================================
***************
*** 1085,1090 **** fetch from c;
--- 1173,1185 ----
  update bar set f2 = null where current of c;
  rollback;
  
+ explain (verbose, costs off)
+ delete from foo where f1 < 5 returning *;
+ delete from foo where f1 < 5 returning *;
+ explain (verbose, costs off)
+ update bar set f2 = f2 + 100 returning *;
+ update bar set f2 = f2 + 100 returning *;
+ 
  drop table foo cascade;
  drop table bar cascade;
  drop table loct1;
*** a/doc/src/sgml/fdwhandler.sgml
--- b/doc/src/sgml/fdwhandler.sgml
***************
*** 698,703 **** IsForeignRelUpdatable (Relation rel);
--- 698,855 ----
       updatability for display in the <literal>information_schema</> views.)
      </para>
  
+     <para>
+      Some inserts, updates, and deletes to foreign tables can be optimized
+      by implementing an alternative set of interfaces.  The ordinary
+      interfaces for inserts, updates, and deletes fetch rows from the remote
+      server and then modify those rows one at a time.  In some cases, this
+      row-by-row approach is necessary, but it can be inefficient.  If it is
+      possible for the foreign server to determine which rows should be
+      modified without actually retrieving them, and if there are no local
+      triggers which would affect the operation, then it is possible to
+      arrange things so that the entire operation is performed on the remote
+      server.  The interfaces described below make this possible.
+     </para>
+ 
+     <para>
+ <programlisting>
+ bool
+ PlanDirectModify (PlannerInfo *root,
+                   ModifyTable *plan,
+                   Index resultRelation,
+                   int subplan_index);
+ </programlisting>
+ 
+      Decide whether it is safe to execute a direct modification
+      on the remote server.  If so, return <literal>true</> after performing
+      planning actions needed for that.  Otherwise, return <literal>false</>.
+      This optional function is called during query planning.
+      If this function succeeds, <function>BeginDirectModify</>,
+      <function>IterateDirectModify</> and <function>EndDirectModify</> will
+      be called at the execution stage, instead.  Otherwise, the table
+      modification will be executed using the table-updating functions
+      described above.
+      The parameters are the same as for <function>PlanForeignModify</>.
+     </para>
+ 
+     <para>
+      To execute the direct modification on the remote server, this function
+      must rewrite the target subplan with a <structname>ForeignScan</> plan
+      node that executes the direct modification on the remote server.  The
+      <structfield>operation</> field of the <structname>ForeignScan</> must
+      be set to the <literal>CmdType</> enumeration appropriately; that is,
+      <literal>CMD_UPDATE</> for <command>UPDATE</>,
+      <literal>CMD_INSERT</> for <command>INSERT</>, and
+      <literal>CMD_DELETE</> for <command>DELETE</>.
+     </para>
+ 
+     <para>
+      See <xref linkend="fdw-planning"> for additional information.
+     </para>
+ 
+     <para>
+      If the <function>PlanDirectModify</> pointer is set to
+      <literal>NULL</>, no attempts to execute a direct modification on the
+      remote server are taken.
+     </para>
+ 
+     <para>
+ <programlisting>
+ void
+ BeginDirectModify (ForeignScanState *node,
+                    int eflags);
+ </programlisting>
+ 
+      Prepare to execute a direct modification on the remote server.
+      This is called during executor startup.  It should perform any
+      initialization needed prior to the direct modification (that should be
+      done upon the first call to <function>IterateDirectModify</>).
+      The <structname>ForeignScanState</> node has already been created, but
+      its <structfield>fdw_state</> field is still NULL.  Information about
+      the table to modify is accessible through the
+      <structname>ForeignScanState</> node (in particular, from the underlying
+      <structname>ForeignScan</> plan node, which contains any FDW-private
+      information provided by <function>PlanDirectModify</>).
+      <literal>eflags</> contains flag bits describing the executor's
+      operating mode for this plan node.
+     </para>
+ 
+     <para>
+      Note that when <literal>(eflags &amp; EXEC_FLAG_EXPLAIN_ONLY)</> is
+      true, this function should not perform any externally-visible actions;
+      it should only do the minimum required to make the node state valid
+      for <function>ExplainDirectModify</> and <function>EndDirectModify</>.
+     </para>
+ 
+     <para>
+      If the <function>BeginDirectModify</> pointer is set to
+      <literal>NULL</>, no attempts to execute a direct modification on the
+      remote server are taken.
+     </para>
+ 
+     <para>
+ <programlisting>
+ TupleTableSlot *
+ IterateDirectModify (ForeignScanState *node);
+ </programlisting>
+ 
+      When the <command>INSERT</>, <command>UPDATE</> or <command>DELETE</>
+      query doesn't have a <literal>RETURNING</> clause, just return NULL
+      after a direct modification on the remote server.
+      When the query has the clause, fetch one result containing the data
+      needed for the <literal>RETURNING</> calculation, returning it in a
+      tuple table slot (the node's <structfield>ScanTupleSlot</> should be
+      used for this purpose).  The data that was actually inserted, updated
+      or deleted must be stored in the
+      <literal>es_result_relation_info-&gt;ri_projectReturning-&gt;pi_exprContext-&gt;ecxt_scantuple</>
+      of the node's <structname>EState</>.
+      Return NULL if no more rows are available.
+      Note that this is called in a short-lived memory context that will be
+      reset between invocations.  Create a memory context in
+      <function>BeginDirectModify</> if you need longer-lived storage, or use
+      the <structfield>es_query_cxt</> of the node's <structname>EState</>.
+     </para>
+ 
+     <para>
+      The rows returned must match the <structfield>fdw_scan_tlist</> target
+      list if one was supplied, otherwise they must match the row type of the
+      foreign table being updated.  If you choose to optimize away fetching
+      columns that are not needed for the <literal>RETURNING</> calculation,
+      you should insert nulls in those column positions, or else generate a
+      <structfield>fdw_scan_tlist</> list with those columns omitted.
+     </para>
+ 
+     <para>
+      Whether the query has the clause or not, the query's reported row count 
+      must be incremented by the FDW itself.  When the query doesn't have the
+      clause, the FDW must also increment the row count for the
+      <structname>ForeignScanState</> node in the <command>EXPLAIN ANALYZE</>
+      case.
+     </para>
+ 
+     <para>
+      If the <function>IterateDirectModify</> pointer is set to
+      <literal>NULL</>, no attempts to execute a direct modification on the
+      remote server are taken.
+     </para>
+ 
+     <para>
+ <programlisting>
+ void
+ EndDirectModify (ForeignScanState *node);
+ </programlisting>
+ 
+      Clean up following a direc modification on the remote server.  It is
+      normally not important to release palloc'd memory, but for example open
+      files and connections to the remote server should be cleaned up.
+     </para>
+ 
+     <para>
+      If the <function>EndDirectModify</> pointer is set to
+      <literal>NULL</>, no attempts to execute a direct modification on the
+      remote server are taken.
+     </para>
+ 
     </sect2>
  
     <sect2 id="fdw-callbacks-row-locking">
***************
*** 889,894 **** ExplainForeignModify (ModifyTableState *mtstate,
--- 1041,1069 ----
       <command>EXPLAIN</>.
      </para>
  
+     <para>
+ <programlisting>
+ void
+ ExplainDirectModify (ForeignScanState *node,
+                      ExplainState *es);
+ </programlisting>
+ 
+      Print additional <command>EXPLAIN</> output for a direct modification
+      on the remote server.
+      This function can call <function>ExplainPropertyText</> and
+      related functions to add fields to the <command>EXPLAIN</> output.
+      The flag fields in <literal>es</> can be used to determine what to
+      print, and the state of the <structname>ForeignScanState</> node
+      can be inspected to provide run-time statistics in the <command>EXPLAIN
+      ANALYZE</> case.
+     </para>
+ 
+     <para>
+      If the <function>ExplainDirectModify</> pointer is set to
+      <literal>NULL</>, no additional information is printed during
+      <command>EXPLAIN</>.
+     </para>
+ 
     </sect2>
  
     <sect2 id="fdw-callbacks-analyze">
***************
*** 1194,1200 **** GetForeignServerByName(const char *name, bool missing_ok);
       The FDW callback functions <function>GetForeignRelSize</>,
       <function>GetForeignPaths</>, <function>GetForeignPlan</>,
       <function>PlanForeignModify</>, <function>GetForeignJoinPaths</>,
!      and <function>GetForeignUpperPaths</>
       must fit into the workings of the <productname>PostgreSQL</> planner.
       Here are some notes about what they must do.
      </para>
--- 1369,1375 ----
       The FDW callback functions <function>GetForeignRelSize</>,
       <function>GetForeignPaths</>, <function>GetForeignPlan</>,
       <function>PlanForeignModify</>, <function>GetForeignJoinPaths</>,
!      <function>GetForeignUpperPaths</>, and <function>PlanDirectModify</>
       must fit into the workings of the <productname>PostgreSQL</> planner.
       Here are some notes about what they must do.
      </para>
***************
*** 1391,1397 **** GetForeignServerByName(const char *name, bool missing_ok);
  
      <para>
       When planning an <command>UPDATE</> or <command>DELETE</>,
!      <function>PlanForeignModify</> can look up the <structname>RelOptInfo</>
       struct for the foreign table and make use of the
       <literal>baserel-&gt;fdw_private</> data previously created by the
       scan-planning functions.  However, in <command>INSERT</> the target
--- 1566,1573 ----
  
      <para>
       When planning an <command>UPDATE</> or <command>DELETE</>,
!      <function>PlanForeignModify</> and <function>PlanDirectModify</>
!      can look up the <structname>RelOptInfo</>
       struct for the foreign table and make use of the
       <literal>baserel-&gt;fdw_private</> data previously created by the
       scan-planning functions.  However, in <command>INSERT</> the target
*** a/doc/src/sgml/postgres-fdw.sgml
--- b/doc/src/sgml/postgres-fdw.sgml
***************
*** 484,489 ****
--- 484,498 ----
     extension that's listed in the foreign server's <literal>extensions</>
     option.  Operators and functions in such clauses must
     be <literal>IMMUTABLE</> as well.
+    For an <command>UPDATE</> or <command>DELETE</> query,
+    <filename>postgres_fdw</> attempts to optimize the query execution by
+    sending the whole query to the remote server if there are no query
+    <literal>WHERE</> clauses that cannot be sent to the remote server,
+    no local joins for the query, and no row-level local <literal>BEFORE</> or
+    <literal>AFTER</> triggers on the target table.  In <command>UPDATE</>,
+    expressions to assign to target columns must use only built-in data types,
+    <literal>IMMUTABLE</> operators, or <literal>IMMUTABLE</> functions,
+    to reduce the risk of misexecution of the query.
    </para>
  
    <para>
*** a/src/backend/commands/explain.c
--- b/src/backend/commands/explain.c
***************
*** 900,906 **** ExplainNode(PlanState *planstate, List *ancestors,
  			pname = sname = "WorkTable Scan";
  			break;
  		case T_ForeignScan:
! 			pname = sname = "Foreign Scan";
  			break;
  		case T_CustomScan:
  			sname = "Custom Scan";
--- 900,928 ----
  			pname = sname = "WorkTable Scan";
  			break;
  		case T_ForeignScan:
! 			sname = "Foreign Scan";
! 			switch (((ForeignScan *) plan)->operation)
! 			{
! 				case CMD_SELECT:
! 					pname = "Foreign Scan";
! 					operation = "Select";
! 					break;
! 				case CMD_INSERT:
! 					pname = "Foreign Insert";
! 					operation = "Insert";
! 					break;
! 				case CMD_UPDATE:
! 					pname = "Foreign Update";
! 					operation = "Update";
! 					break;
! 				case CMD_DELETE:
! 					pname = "Foreign Delete";
! 					operation = "Delete";
! 					break;
! 				default:
! 					pname = "???";
! 					break;
! 			}
  			break;
  		case T_CustomScan:
  			sname = "Custom Scan";
***************
*** 1648,1653 **** show_plan_tlist(PlanState *planstate, List *ancestors, ExplainState *es)
--- 1670,1688 ----
  		return;
  	if (IsA(plan, RecursiveUnion))
  		return;
+ 	/*
+ 	 * Likewise for ForeignScan that executes a direct INSERT/UPDATE/DELETE
+ 	 *
+ 	 * Note: the tlist for a ForeignScan that executes a direct INSERT/UPDATE
+ 	 * might contain subplan output expressions that are confusing in this
+ 	 * context.  The tlist for a ForeignScan that executes a direct UPDATE/
+ 	 * DELETE always contains "junk" target columns to identify the exact row
+ 	 * to update or delete, which would be confusing in this context.  So, we
+ 	 * suppress it in all the cases.
+ 	 */
+ 	if (IsA(plan, ForeignScan) &&
+ 		((ForeignScan *) plan)->operation != CMD_SELECT)
+ 		return;
  
  	/* Set up deparsing context */
  	context = set_deparse_context_planstate(es->deparse_cxt,
***************
*** 2236,2243 **** show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es)
  	FdwRoutine *fdwroutine = fsstate->fdwroutine;
  
  	/* Let the FDW emit whatever fields it wants */
! 	if (fdwroutine->ExplainForeignScan != NULL)
! 		fdwroutine->ExplainForeignScan(fsstate, es);
  }
  
  /*
--- 2271,2286 ----
  	FdwRoutine *fdwroutine = fsstate->fdwroutine;
  
  	/* Let the FDW emit whatever fields it wants */
! 	if (((ForeignScan *) fsstate->ss.ps.plan)->operation != CMD_SELECT)
! 	{
! 		if (fdwroutine->ExplainDirectModify != NULL)
! 			fdwroutine->ExplainDirectModify(fsstate, es);
! 	}
! 	else
! 	{
! 		if (fdwroutine->ExplainForeignScan != NULL)
! 			fdwroutine->ExplainForeignScan(fsstate, es);
! 	}
  }
  
  /*
***************
*** 2623,2630 **** show_modifytable_info(ModifyTableState *mtstate, List *ancestors,
  			}
  		}
  
! 		/* Give FDW a chance */
! 		if (fdwroutine && fdwroutine->ExplainForeignModify != NULL)
  		{
  			List	   *fdw_private = (List *) list_nth(node->fdwPrivLists, j);
  
--- 2666,2675 ----
  			}
  		}
  
! 		/* Give FDW a chance if needed */
! 		if (!resultRelInfo->ri_usesFdwDirectModify &&
! 			fdwroutine != NULL &&
! 			fdwroutine->ExplainForeignModify != NULL)
  		{
  			List	   *fdw_private = (List *) list_nth(node->fdwPrivLists, j);
  
*** a/src/backend/executor/execMain.c
--- b/src/backend/executor/execMain.c
***************
*** 1245,1250 **** InitResultRelInfo(ResultRelInfo *resultRelInfo,
--- 1245,1251 ----
  	else
  		resultRelInfo->ri_FdwRoutine = NULL;
  	resultRelInfo->ri_FdwState = NULL;
+ 	resultRelInfo->ri_usesFdwDirectModify = false;
  	resultRelInfo->ri_ConstraintExprs = NULL;
  	resultRelInfo->ri_junkFilter = NULL;
  	resultRelInfo->ri_projectReturning = NULL;
*** a/src/backend/executor/nodeForeignscan.c
--- b/src/backend/executor/nodeForeignscan.c
***************
*** 48,54 **** ForeignNext(ForeignScanState *node)
  
  	/* Call the Iterate function in short-lived context */
  	oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
! 	slot = node->fdwroutine->IterateForeignScan(node);
  	MemoryContextSwitchTo(oldcontext);
  
  	/*
--- 48,57 ----
  
  	/* Call the Iterate function in short-lived context */
  	oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
! 	if (plan->operation != CMD_SELECT)
! 		slot = node->fdwroutine->IterateDirectModify(node);
! 	else
! 		slot = node->fdwroutine->IterateForeignScan(node);
  	MemoryContextSwitchTo(oldcontext);
  
  	/*
***************
*** 226,232 **** ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
  	/*
  	 * Tell the FDW to initialize the scan.
  	 */
! 	fdwroutine->BeginForeignScan(scanstate, eflags);
  
  	return scanstate;
  }
--- 229,238 ----
  	/*
  	 * Tell the FDW to initialize the scan.
  	 */
! 	if (node->operation != CMD_SELECT)
! 		fdwroutine->BeginDirectModify(scanstate, eflags);
! 	else
! 		fdwroutine->BeginForeignScan(scanstate, eflags);
  
  	return scanstate;
  }
***************
*** 240,247 **** ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
  void
  ExecEndForeignScan(ForeignScanState *node)
  {
  	/* Let the FDW shut down */
! 	node->fdwroutine->EndForeignScan(node);
  
  	/* Shut down any outer plan. */
  	if (outerPlanState(node))
--- 246,258 ----
  void
  ExecEndForeignScan(ForeignScanState *node)
  {
+ 	ForeignScan *plan = (ForeignScan *) node->ss.ps.plan;
+ 
  	/* Let the FDW shut down */
! 	if (plan->operation != CMD_SELECT)
! 		node->fdwroutine->EndDirectModify(node);
! 	else
! 		node->fdwroutine->EndForeignScan(node);
  
  	/* Shut down any outer plan. */
  	if (outerPlanState(node))
*** a/src/backend/executor/nodeModifyTable.c
--- b/src/backend/executor/nodeModifyTable.c
***************
*** 138,150 **** ExecCheckPlanOutput(Relation resultRel, List *targetList)
   * tupleSlot: slot holding tuple actually inserted/updated/deleted
   * planSlot: slot holding tuple returned by top subplan node
   *
   * Returns a slot holding the result tuple
   */
  static TupleTableSlot *
! ExecProcessReturning(ProjectionInfo *projectReturning,
  					 TupleTableSlot *tupleSlot,
  					 TupleTableSlot *planSlot)
  {
  	ExprContext *econtext = projectReturning->pi_exprContext;
  
  	/*
--- 138,154 ----
   * tupleSlot: slot holding tuple actually inserted/updated/deleted
   * planSlot: slot holding tuple returned by top subplan node
   *
+  * Note: If tupleSlot is NULL, the FDW should have already provided econtext's
+  * scan tuple.
+  *
   * Returns a slot holding the result tuple
   */
  static TupleTableSlot *
! ExecProcessReturning(ResultRelInfo *resultRelInfo,
  					 TupleTableSlot *tupleSlot,
  					 TupleTableSlot *planSlot)
  {
+ 	ProjectionInfo *projectReturning = resultRelInfo->ri_projectReturning;
  	ExprContext *econtext = projectReturning->pi_exprContext;
  
  	/*
***************
*** 154,160 **** ExecProcessReturning(ProjectionInfo *projectReturning,
  	ResetExprContext(econtext);
  
  	/* Make tuple and any needed join variables available to ExecProject */
! 	econtext->ecxt_scantuple = tupleSlot;
  	econtext->ecxt_outertuple = planSlot;
  
  	/* Compute the RETURNING expressions */
--- 158,177 ----
  	ResetExprContext(econtext);
  
  	/* Make tuple and any needed join variables available to ExecProject */
! 	if (tupleSlot)
! 		econtext->ecxt_scantuple = tupleSlot;
! 	else
! 	{
! 		HeapTuple	tuple;
! 
! 		/*
! 		 * RETURNING expressions might reference the tableoid column, so
! 		 * initialize t_tableOid before evaluating them.
! 		 */
! 		Assert(!TupIsNull(econtext->ecxt_scantuple));
! 		tuple = ExecMaterializeSlot(econtext->ecxt_scantuple);
! 		tuple->t_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
! 	}
  	econtext->ecxt_outertuple = planSlot;
  
  	/* Compute the RETURNING expressions */
***************
*** 496,503 **** ExecInsert(ModifyTableState *mtstate,
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning)
! 		return ExecProcessReturning(resultRelInfo->ri_projectReturning,
! 									slot, planSlot);
  
  	return NULL;
  }
--- 513,519 ----
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning)
! 		return ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  	return NULL;
  }
***************
*** 738,745 **** ldelete:;
  			ExecStoreTuple(&deltuple, slot, InvalidBuffer, false);
  		}
  
! 		rslot = ExecProcessReturning(resultRelInfo->ri_projectReturning,
! 									 slot, planSlot);
  
  		/*
  		 * Before releasing the target tuple again, make sure rslot has a
--- 754,760 ----
  			ExecStoreTuple(&deltuple, slot, InvalidBuffer, false);
  		}
  
! 		rslot = ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  		/*
  		 * Before releasing the target tuple again, make sure rslot has a
***************
*** 1024,1031 **** lreplace:;
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning)
! 		return ExecProcessReturning(resultRelInfo->ri_projectReturning,
! 									slot, planSlot);
  
  	return NULL;
  }
--- 1039,1045 ----
  
  	/* Process RETURNING if present */
  	if (resultRelInfo->ri_projectReturning)
! 		return ExecProcessReturning(resultRelInfo, slot, planSlot);
  
  	return NULL;
  }
***************
*** 1380,1385 **** ExecModifyTable(ModifyTableState *node)
--- 1394,1419 ----
  				break;
  		}
  
+ 		/*
+ 		 * If resultRelInfo->ri_usesFdwDirectModify is true, all we need to do
+ 		 * here is compute the RETURNING expressions.
+ 		 */
+ 		if (resultRelInfo->ri_usesFdwDirectModify)
+ 		{
+ 			Assert(resultRelInfo->ri_projectReturning);
+ 
+ 			/*
+ 			 * A scan slot containing the data that was actually inserted,
+ 			 * updated or deleted has already been made available to
+ 			 * ExecProcessReturning by IterateDirectModify, so no need to
+ 			 * provide it here.
+ 			 */
+ 			slot = ExecProcessReturning(resultRelInfo, NULL, planSlot);
+ 
+ 			estate->es_result_relation_info = saved_resultRelInfo;
+ 			return slot;
+ 		}
+ 
  		EvalPlanQualSetSlot(&node->mt_epqstate, planSlot);
  		slot = planSlot;
  
***************
*** 1559,1564 **** ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
--- 1593,1602 ----
  	{
  		subplan = (Plan *) lfirst(l);
  
+ 		/* Initialize the usesFdwDirectModify flag */
+ 		resultRelInfo->ri_usesFdwDirectModify = bms_is_member(i,
+ 												node->fdwDirectModifyPlans);
+ 
  		/*
  		 * Verify result relation is a valid target for the current operation
  		 */
***************
*** 1583,1589 **** ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
  		mtstate->mt_plans[i] = ExecInitNode(subplan, estate, eflags);
  
  		/* Also let FDWs init themselves for foreign-table result rels */
! 		if (resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->BeginForeignModify != NULL)
  		{
  			List	   *fdw_private = (List *) list_nth(node->fdwPrivLists, i);
--- 1621,1628 ----
  		mtstate->mt_plans[i] = ExecInitNode(subplan, estate, eflags);
  
  		/* Also let FDWs init themselves for foreign-table result rels */
! 		if (!resultRelInfo->ri_usesFdwDirectModify &&
! 			resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->BeginForeignModify != NULL)
  		{
  			List	   *fdw_private = (List *) list_nth(node->fdwPrivLists, i);
***************
*** 1910,1916 **** ExecEndModifyTable(ModifyTableState *node)
  	{
  		ResultRelInfo *resultRelInfo = node->resultRelInfo + i;
  
! 		if (resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->EndForeignModify != NULL)
  			resultRelInfo->ri_FdwRoutine->EndForeignModify(node->ps.state,
  														   resultRelInfo);
--- 1949,1956 ----
  	{
  		ResultRelInfo *resultRelInfo = node->resultRelInfo + i;
  
! 		if (!resultRelInfo->ri_usesFdwDirectModify &&
! 			resultRelInfo->ri_FdwRoutine != NULL &&
  			resultRelInfo->ri_FdwRoutine->EndForeignModify != NULL)
  			resultRelInfo->ri_FdwRoutine->EndForeignModify(node->ps.state,
  														   resultRelInfo);
*** a/src/backend/nodes/copyfuncs.c
--- b/src/backend/nodes/copyfuncs.c
***************
*** 188,193 **** _copyModifyTable(const ModifyTable *from)
--- 188,194 ----
  	COPY_NODE_FIELD(withCheckOptionLists);
  	COPY_NODE_FIELD(returningLists);
  	COPY_NODE_FIELD(fdwPrivLists);
+ 	COPY_BITMAPSET_FIELD(fdwDirectModifyPlans);
  	COPY_NODE_FIELD(rowMarks);
  	COPY_SCALAR_FIELD(epqParam);
  	COPY_SCALAR_FIELD(onConflictAction);
***************
*** 648,653 **** _copyForeignScan(const ForeignScan *from)
--- 649,655 ----
  	/*
  	 * copy remainder of node
  	 */
+ 	COPY_SCALAR_FIELD(operation);
  	COPY_SCALAR_FIELD(fs_server);
  	COPY_NODE_FIELD(fdw_exprs);
  	COPY_NODE_FIELD(fdw_private);
*** a/src/backend/nodes/outfuncs.c
--- b/src/backend/nodes/outfuncs.c
***************
*** 356,361 **** _outModifyTable(StringInfo str, const ModifyTable *node)
--- 356,362 ----
  	WRITE_NODE_FIELD(withCheckOptionLists);
  	WRITE_NODE_FIELD(returningLists);
  	WRITE_NODE_FIELD(fdwPrivLists);
+ 	WRITE_BITMAPSET_FIELD(fdwDirectModifyPlans);
  	WRITE_NODE_FIELD(rowMarks);
  	WRITE_INT_FIELD(epqParam);
  	WRITE_ENUM_FIELD(onConflictAction, OnConflictAction);
***************
*** 608,613 **** _outForeignScan(StringInfo str, const ForeignScan *node)
--- 609,615 ----
  
  	_outScanInfo(str, (const Scan *) node);
  
+ 	WRITE_ENUM_FIELD(operation, CmdType);
  	WRITE_OID_FIELD(fs_server);
  	WRITE_NODE_FIELD(fdw_exprs);
  	WRITE_NODE_FIELD(fdw_private);
*** a/src/backend/nodes/readfuncs.c
--- b/src/backend/nodes/readfuncs.c
***************
*** 1481,1486 **** _readModifyTable(void)
--- 1481,1487 ----
  	READ_NODE_FIELD(withCheckOptionLists);
  	READ_NODE_FIELD(returningLists);
  	READ_NODE_FIELD(fdwPrivLists);
+ 	READ_BITMAPSET_FIELD(fdwDirectModifyPlans);
  	READ_NODE_FIELD(rowMarks);
  	READ_INT_FIELD(epqParam);
  	READ_ENUM_FIELD(onConflictAction, OnConflictAction);
*** a/src/backend/optimizer/plan/createplan.c
--- b/src/backend/optimizer/plan/createplan.c
***************
*** 4903,4908 **** make_foreignscan(List *qptlist,
--- 4903,4909 ----
  	plan->lefttree = outer_plan;
  	plan->righttree = NULL;
  	node->scan.scanrelid = scanrelid;
+ 	node->operation = CMD_SELECT;
  	/* fs_server will be filled in by create_foreignscan_plan */
  	node->fs_server = InvalidOid;
  	node->fdw_exprs = fdw_exprs;
***************
*** 6018,6023 **** make_modifytable(PlannerInfo *root,
--- 6019,6025 ----
  {
  	ModifyTable *node = makeNode(ModifyTable);
  	List	   *fdw_private_list;
+ 	Bitmapset  *direct_modify_plans;
  	ListCell   *lc;
  	int			i;
  
***************
*** 6075,6086 **** make_modifytable(PlannerInfo *root,
--- 6077,6090 ----
  	 * construct private plan data, and accumulate it all into a list.
  	 */
  	fdw_private_list = NIL;
+ 	direct_modify_plans = NULL;
  	i = 0;
  	foreach(lc, resultRelations)
  	{
  		Index		rti = lfirst_int(lc);
  		FdwRoutine *fdwroutine;
  		List	   *fdw_private;
+ 		bool		direct_modify;
  
  		/*
  		 * If possible, we want to get the FdwRoutine from our RelOptInfo for
***************
*** 6107,6113 **** make_modifytable(PlannerInfo *root,
--- 6111,6133 ----
  				fdwroutine = NULL;
  		}
  
+ 		/*
+ 		 * If the target foreign table has any row-level triggers, we can't
+ 		 * modify the foreign table directly.
+ 		 */
+ 		direct_modify = false;
  		if (fdwroutine != NULL &&
+ 			fdwroutine->PlanDirectModify != NULL &&
+ 			fdwroutine->BeginDirectModify != NULL &&
+ 			fdwroutine->IterateDirectModify != NULL &&
+ 			fdwroutine->EndDirectModify != NULL &&
+ 			!has_row_triggers(root, rti, operation))
+ 			direct_modify = fdwroutine->PlanDirectModify(root, node, rti, i);
+ 		if (direct_modify)
+ 			direct_modify_plans = bms_add_member(direct_modify_plans, i);
+ 
+ 		if (!direct_modify &&
+ 			fdwroutine != NULL &&
  			fdwroutine->PlanForeignModify != NULL)
  			fdw_private = fdwroutine->PlanForeignModify(root, node, rti, i);
  		else
***************
*** 6116,6121 **** make_modifytable(PlannerInfo *root,
--- 6136,6142 ----
  		i++;
  	}
  	node->fdwPrivLists = fdw_private_list;
+ 	node->fdwDirectModifyPlans = direct_modify_plans;
  
  	return node;
  }
*** a/src/backend/optimizer/util/plancat.c
--- b/src/backend/optimizer/util/plancat.c
***************
*** 1540,1542 **** has_unique_index(RelOptInfo *rel, AttrNumber attno)
--- 1540,1589 ----
  	}
  	return false;
  }
+ 
+ 
+ /*
+  * has_row_triggers
+  *
+  * Detect whether the specified relation has any row-level triggers for event.
+  */
+ bool
+ has_row_triggers(PlannerInfo *root, Index rti, CmdType event)
+ {
+ 	RangeTblEntry *rte = planner_rt_fetch(rti, root);
+ 	Relation	relation;
+ 	TriggerDesc *trigDesc;
+ 	bool		result = false;
+ 
+ 	/* Assume we already have adequate lock */
+ 	relation = heap_open(rte->relid, NoLock);
+ 
+ 	trigDesc = relation->trigdesc;
+ 	switch (event)
+ 	{
+ 		case CMD_INSERT:
+ 			if (trigDesc &&
+ 				(trigDesc->trig_insert_after_row ||
+ 				 trigDesc->trig_insert_before_row))
+ 				result = true;
+ 			break;
+ 		case CMD_UPDATE:
+ 			if (trigDesc &&
+ 				(trigDesc->trig_update_after_row ||
+ 				 trigDesc->trig_update_before_row))
+ 				result = true;
+ 			break;
+ 		case CMD_DELETE:
+ 			if (trigDesc &&
+ 				(trigDesc->trig_delete_after_row ||
+ 				 trigDesc->trig_delete_before_row))
+ 				result = true;
+ 			break;
+ 		default:
+ 			elog(ERROR, "unrecognized CmdType: %d", (int) event);
+ 			break;
+ 	}
+ 
+ 	heap_close(relation, NoLock);
+ 	return result;
+ }
*** a/src/include/foreign/fdwapi.h
--- b/src/include/foreign/fdwapi.h
***************
*** 97,102 **** typedef void (*EndForeignModify_function) (EState *estate,
--- 97,114 ----
  
  typedef int (*IsForeignRelUpdatable_function) (Relation rel);
  
+ typedef bool (*PlanDirectModify_function) (PlannerInfo *root,
+ 										   ModifyTable *plan,
+ 										   Index resultRelation,
+ 										   int subplan_index);
+ 
+ typedef void (*BeginDirectModify_function) (ForeignScanState *node,
+ 											int eflags);
+ 
+ typedef TupleTableSlot *(*IterateDirectModify_function) (ForeignScanState *node);
+ 
+ typedef void (*EndDirectModify_function) (ForeignScanState *node);
+ 
  typedef RowMarkType (*GetForeignRowMarkType_function) (RangeTblEntry *rte,
  												LockClauseStrength strength);
  
***************
*** 114,119 **** typedef void (*ExplainForeignModify_function) (ModifyTableState *mtstate,
--- 126,134 ----
  														   int subplan_index,
  													struct ExplainState *es);
  
+ typedef void (*ExplainDirectModify_function) (ForeignScanState *node,
+ 													struct ExplainState *es);
+ 
  typedef int (*AcquireSampleRowsFunc) (Relation relation, int elevel,
  											   HeapTuple *rows, int targrows,
  												  double *totalrows,
***************
*** 181,186 **** typedef struct FdwRoutine
--- 196,205 ----
  	ExecForeignDelete_function ExecForeignDelete;
  	EndForeignModify_function EndForeignModify;
  	IsForeignRelUpdatable_function IsForeignRelUpdatable;
+ 	PlanDirectModify_function PlanDirectModify;
+ 	BeginDirectModify_function BeginDirectModify;
+ 	IterateDirectModify_function IterateDirectModify;
+ 	EndDirectModify_function EndDirectModify;
  
  	/* Functions for SELECT FOR UPDATE/SHARE row locking */
  	GetForeignRowMarkType_function GetForeignRowMarkType;
***************
*** 190,195 **** typedef struct FdwRoutine
--- 209,215 ----
  	/* Support functions for EXPLAIN */
  	ExplainForeignScan_function ExplainForeignScan;
  	ExplainForeignModify_function ExplainForeignModify;
+ 	ExplainDirectModify_function ExplainDirectModify;
  
  	/* Support functions for ANALYZE */
  	AnalyzeForeignTable_function AnalyzeForeignTable;
*** a/src/include/nodes/execnodes.h
--- b/src/include/nodes/execnodes.h
***************
*** 311,316 **** typedef struct JunkFilter
--- 311,317 ----
   *		TrigInstrument			optional runtime measurements for triggers
   *		FdwRoutine				FDW callback functions, if foreign table
   *		FdwState				available to save private state of FDW
+  *		usesFdwDirectModify		true when modifying foreign table directly
   *		WithCheckOptions		list of WithCheckOption's to be checked
   *		WithCheckOptionExprs	list of WithCheckOption expr states
   *		ConstraintExprs			array of constraint-checking expr states
***************
*** 334,339 **** typedef struct ResultRelInfo
--- 335,341 ----
  	Instrumentation *ri_TrigInstrument;
  	struct FdwRoutine *ri_FdwRoutine;
  	void	   *ri_FdwState;
+ 	bool		ri_usesFdwDirectModify;
  	List	   *ri_WithCheckOptions;
  	List	   *ri_WithCheckOptionExprs;
  	List	  **ri_ConstraintExprs;
*** a/src/include/nodes/pg_list.h
--- b/src/include/nodes/pg_list.h
***************
*** 134,149 **** list_length(const List *l)
--- 134,152 ----
  #define list_make2(x1,x2)			lcons(x1, list_make1(x2))
  #define list_make3(x1,x2,x3)		lcons(x1, list_make2(x2, x3))
  #define list_make4(x1,x2,x3,x4)		lcons(x1, list_make3(x2, x3, x4))
+ #define list_make5(x1,x2,x3,x4,x5)	lcons(x1, list_make4(x2, x3, x4, x5))
  
  #define list_make1_int(x1)			lcons_int(x1, NIL)
  #define list_make2_int(x1,x2)		lcons_int(x1, list_make1_int(x2))
  #define list_make3_int(x1,x2,x3)	lcons_int(x1, list_make2_int(x2, x3))
  #define list_make4_int(x1,x2,x3,x4) lcons_int(x1, list_make3_int(x2, x3, x4))
+ #define list_make5_int(x1,x2,x3,x4,x5)	lcons_int(x1, list_make4_int(x2, x3, x4, x5))
  
  #define list_make1_oid(x1)			lcons_oid(x1, NIL)
  #define list_make2_oid(x1,x2)		lcons_oid(x1, list_make1_oid(x2))
  #define list_make3_oid(x1,x2,x3)	lcons_oid(x1, list_make2_oid(x2, x3))
  #define list_make4_oid(x1,x2,x3,x4) lcons_oid(x1, list_make3_oid(x2, x3, x4))
+ #define list_make5_oid(x1,x2,x3,x4,x5)	lcons_oid(x1, list_make4_oid(x2, x3, x4, x5))
  
  /*
   * foreach -
*** a/src/include/nodes/plannodes.h
--- b/src/include/nodes/plannodes.h
***************
*** 189,194 **** typedef struct ModifyTable
--- 189,195 ----
  	List	   *withCheckOptionLists;	/* per-target-table WCO lists */
  	List	   *returningLists; /* per-target-table RETURNING tlists */
  	List	   *fdwPrivLists;	/* per-target-table FDW private data lists */
+ 	Bitmapset  *fdwDirectModifyPlans;	/* indices of FDW DM plans */
  	List	   *rowMarks;		/* PlanRowMarks (non-locking only) */
  	int			epqParam;		/* ID of Param for EvalPlanQual re-eval */
  	OnConflictAction onConflictAction;	/* ON CONFLICT action */
***************
*** 531,536 **** typedef struct WorkTableScan
--- 532,538 ----
  typedef struct ForeignScan
  {
  	Scan		scan;
+ 	CmdType		operation;		/* SELECT/INSERT/UPDATE/DELETE */
  	Oid			fs_server;		/* OID of foreign server */
  	List	   *fdw_exprs;		/* expressions that FDW may evaluate */
  	List	   *fdw_private;	/* private data for FDW */
*** a/src/include/optimizer/plancat.h
--- b/src/include/optimizer/plancat.h
***************
*** 55,58 **** extern Selectivity join_selectivity(PlannerInfo *root,
--- 55,60 ----
  				 JoinType jointype,
  				 SpecialJoinInfo *sjinfo);
  
+ extern bool has_row_triggers(PlannerInfo *root, Index rti, CmdType event);
+ 
  #endif   /* PLANCAT_H */
-- 
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