Fix planner's row-mark code for inheritance from a foreign table.

Commit 428b260f8 broke planning of cases where row marks are needed
(SELECT FOR UPDATE, etc) and one of the query's tables is a foreign
table that has regular table(s) as inheritance children.  We got the
reverse case right, but apparently were thinking that foreign tables
couldn't be inheritance parents.  Not so; so we need to be able to
add a CTID junk column while adding a new child, not only a wholerow
junk column.

Back-patch to v12 where the faulty code came in.

Amit Langote

Discussion: https://postgr.es/m/CA+HiwqEmo3FV1LAQ4TVyS2h1WM=kMkZUmbNuZSCnfHvMcUcPeA@mail.gmail.com

1 files changed, 21 insertions, 0 deletions

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 78379bdea5b..17dba77d7ec 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1891,6 +1891,27 @@ explain (verbose, costs off)
 select * from bar where f1 in (select f1 from foo) for share;
 select * from bar where f1 in (select f1 from foo) for share;
 
+-- Now check SELECT FOR UPDATE/SHARE with an inherited source table,
+-- where the parent is itself a foreign table
+create table loct4 (f1 int, f2 int, f3 int);
+create foreign table foo2child (f3 int) inherits (foo2)
+  server loopback options (table_name 'loct4');
+
+explain (verbose, costs off)
+select * from bar where f1 in (select f1 from foo2) for share;
+select * from bar where f1 in (select f1 from foo2) for share;
+
+drop foreign table foo2child;
+
+-- And with a local child relation of the foreign table parent
+create table foo2child (f3 int) inherits (foo2);
+
+explain (verbose, costs off)
+select * from bar where f1 in (select f1 from foo2) for share;
+select * from bar where f1 in (select f1 from foo2) for share;
+
+drop table foo2child;
+
 -- Check UPDATE with inherited target and an inherited source table
 explain (verbose, costs off)
 update bar set f2 = f2 + 100 where f1 in (select f1 from foo);