From 8b6da83d162cb0ac9f6d21082727bbd45c972c53 Mon Sep 17 00:00:00 2001
From: Etsuro Fujita <efujita@postgresql.org>
Date: Thu, 13 Jun 2019 17:59:09 +0900
Subject: postgres_fdw: Account for triggers in non-direct remote UPDATE
 planning.

Previously, in postgresPlanForeignModify, we planned an UPDATE operation
on a foreign table so that we transmit only columns that were explicitly
targets of the UPDATE, so as to avoid unnecessary data transmission, but
if there were BEFORE ROW UPDATE triggers on the foreign table, those
triggers might change values for non-target columns, in which case we
would miss sending changed values for those columns.  Prevent optimizing
away transmitting all columns if there are BEFORE ROW UPDATE triggers on
the foreign table.

This is an oversight in commit 7cbe57c34 which added triggers on foreign
tables, so apply the patch all the way back to 9.4 where that came in.

Author: Shohei Mochizuki
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/201905270152.x4R1q3qi014550@toshiba.co.jp
---
 contrib/postgres_fdw/sql/postgres_fdw.sql | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'contrib/postgres_fdw/sql/postgres_fdw.sql')

diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 73852f1ae69..2a8e6c7b282 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1553,6 +1553,11 @@ SELECT * from loc1;
 UPDATE rem1 set f2 = 'skidoo' RETURNING f2;
 SELECT * from loc1;
 
+EXPLAIN (verbose, costs off)
+UPDATE rem1 set f1 = 10;          -- all columns should be transmitted
+UPDATE rem1 set f1 = 10;
+SELECT * from loc1;
+
 DELETE FROM rem1;
 
 -- Add a second trigger, to check that the changes are propagated correctly
-- 
cgit v1.2.3

