Fix whole-row references in postgres_fdw.

The optimization to not retrieve unnecessary columns wasn't smart enough.
Noted by Thom Brown.

3 files changed, 39 insertions, 1 deletions

diff --git a/contrib/postgres_fdw/deparse.c b/contrib/postgres_fdw/deparse.c
index 93f2541cfc1..0293115054f 100644
--- a/contrib/postgres_fdw/deparse.c
+++ b/contrib/postgres_fdw/deparse.c
@@ -364,6 +364,7 @@ deparseSimpleSql(StringInfo buf,
 {
 	RangeTblEntry *rte = root->simple_rte_array[baserel->relid];
 	Bitmapset  *attrs_used = NULL;
+	bool		have_wholerow;
 	bool		first;
 	AttrNumber	attr;
 	ListCell   *lc;
@@ -381,6 +382,10 @@ deparseSimpleSql(StringInfo buf,
 					   &attrs_used);
 	}
 
+	/* If there's a whole-row reference, we'll need all the columns. */
+	have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
+								  attrs_used);
+
 	/*
 	 * Construct SELECT list
 	 *
@@ -401,7 +406,8 @@ deparseSimpleSql(StringInfo buf,
 			appendStringInfo(buf, ", ");
 		first = false;
 
-		if (bms_is_member(attr - FirstLowInvalidHeapAttributeNumber,
+		if (have_wholerow ||
+			bms_is_member(attr - FirstLowInvalidHeapAttributeNumber,
 						  attrs_used))
 			deparseColumnRef(buf, baserel->relid, attr, root);
 		else
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 8af496a5467..f8418baba30 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -180,6 +180,35 @@ SELECT * FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
  110 |  0 | 00110 | Sun Jan 11 00:00:00 1970 PST | Sun Jan 11 00:00:00 1970 | 0  | 0          | foo
 (10 rows)
 
+-- whole-row reference
+EXPLAIN (VERBOSE, COSTS false) SELECT t1 FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                     QUERY PLAN                                      
+-------------------------------------------------------------------------------------
+ Limit
+   Output: t1.*, c3, c1
+   ->  Sort
+         Output: t1.*, c3, c1
+         Sort Key: t1.c3, t1.c1
+         ->  Foreign Scan on public.ft1 t1
+               Output: t1.*, c3, c1
+               Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1"
+(8 rows)
+
+SELECT t1 FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+                                             t1                                             
+--------------------------------------------------------------------------------------------
+ (101,1,00101,"Fri Jan 02 00:00:00 1970 PST","Fri Jan 02 00:00:00 1970",1,"1         ",foo)
+ (102,2,00102,"Sat Jan 03 00:00:00 1970 PST","Sat Jan 03 00:00:00 1970",2,"2         ",foo)
+ (103,3,00103,"Sun Jan 04 00:00:00 1970 PST","Sun Jan 04 00:00:00 1970",3,"3         ",foo)
+ (104,4,00104,"Mon Jan 05 00:00:00 1970 PST","Mon Jan 05 00:00:00 1970",4,"4         ",foo)
+ (105,5,00105,"Tue Jan 06 00:00:00 1970 PST","Tue Jan 06 00:00:00 1970",5,"5         ",foo)
+ (106,6,00106,"Wed Jan 07 00:00:00 1970 PST","Wed Jan 07 00:00:00 1970",6,"6         ",foo)
+ (107,7,00107,"Thu Jan 08 00:00:00 1970 PST","Thu Jan 08 00:00:00 1970",7,"7         ",foo)
+ (108,8,00108,"Fri Jan 09 00:00:00 1970 PST","Fri Jan 09 00:00:00 1970",8,"8         ",foo)
+ (109,9,00109,"Sat Jan 10 00:00:00 1970 PST","Sat Jan 10 00:00:00 1970",9,"9         ",foo)
+ (110,0,00110,"Sun Jan 11 00:00:00 1970 PST","Sun Jan 11 00:00:00 1970",0,"0         ",foo)
+(10 rows)
+
 -- empty result
 SELECT * FROM ft1 WHERE false;
  c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8 
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 0fb2b41117c..8569474694e 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -136,6 +136,9 @@ EXPLAIN (COSTS false) SELECT * FROM ft1 ORDER BY c3, c1 OFFSET 100 LIMIT 10;
 SELECT * FROM ft1 ORDER BY c3, c1 OFFSET 100 LIMIT 10;
 EXPLAIN (VERBOSE, COSTS false) SELECT * FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
 SELECT * FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+-- whole-row reference
+EXPLAIN (VERBOSE, COSTS false) SELECT t1 FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
+SELECT t1 FROM ft1 t1 ORDER BY t1.c3, t1.c1 OFFSET 100 LIMIT 10;
 -- empty result
 SELECT * FROM ft1 WHERE false;
 -- with WHERE clause