From 6be84eeb8d5a72014b1b6e44d0646f69531a1ccf Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Mon, 14 Mar 2016 14:27:11 -0400
Subject: [PATCH] Update more comments for
 96198d94cb7adc664bda341842dc8db671d8be72.

Etsuro Fujita, reviewed (though not completely endorsed) by Ashutosh
Bapat, and slightly expanded by me.
---
 contrib/postgres_fdw/postgres_fdw.c   | 6 ++----
 src/backend/optimizer/path/joinpath.c | 3 ++-
 src/include/nodes/relation.h          | 4 +++-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 40bffd6f6cb..aa745f237e2 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -3349,10 +3349,8 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
  *
  * 1) Join type is INNER or OUTER (one of LEFT/RIGHT/FULL)
  * 2) Both outer and inner portions are safe to push-down
- * 3) All foreign tables in the join belong to the same foreign server and use
- *	  the same user mapping.
- * 4) All join conditions are safe to push down
- * 5) No relation has local filter (this can be relaxed for INNER JOIN, if we
+ * 3) All join conditions are safe to push down
+ * 4) No relation has local filter (this can be relaxed for INNER JOIN, if we
  *	  can move unpushable clauses upwards in the join tree).
  */
 static bool
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index 3b898dafee1..f3aced3c931 100644
--- a/src/backend/optimizer/path/joinpath.c
+++ b/src/backend/optimizer/path/joinpath.c
@@ -213,7 +213,8 @@ add_paths_to_joinrel(PlannerInfo *root,
 
 	/*
 	 * 5. If inner and outer relations are foreign tables (or joins) belonging
-	 * to the same server, give the FDW a chance to push down joins.
+	 * to the same server and using the same user mapping, give the FDW a
+	 * chance to push down joins.
 	 */
 	if (joinrel->fdwroutine &&
 		joinrel->fdwroutine->GetForeignJoinPaths)
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 641728bb0f4..bdea72c3f47 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -448,9 +448,11 @@ typedef struct PlannerInfo
  *		in just as for a baserel, except we don't bother with lateral_vars.
  *
  * If the relation is either a foreign table or a join of foreign tables that
- * all belong to the same foreign server, these fields will be set:
+ * all belong to the same foreign server and use the same user mapping, these
+ * fields will be set:
  *
  *		serverid - OID of foreign server, if foreign table (else InvalidOid)
+ *		umid - OID of user mapping, if foreign table (else InvalidOid)
  *		fdwroutine - function hooks for FDW, if foreign table (else NULL)
  *		fdw_private - private state for FDW, if foreign table (else NULL)
  *
-- 
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