3 files changed, 52 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 70a925c63a1..b22b36ec0ef 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -497,8 +497,9 @@ canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation)
 
 	/*
 	 * For a polymorphic-input-type opclass, just keep the same exposed type.
+	 * RECORD opclasses work like polymorphic-type ones for this purpose.
 	 */
-	if (IsPolymorphicType(req_type))
+	if (IsPolymorphicType(req_type) || req_type == RECORDOID)
 		req_type = expr_type;
 
 	/*
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index cbc882d47ba..dc6262be43a 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -2674,6 +2674,36 @@ select * from a left join b on i = x and i = y and x = i;
 
 rollback;
 --
+-- test handling of merge clauses using record_ops
+--
+begin;
+create type mycomptype as (id int, v bigint);
+create temp table tidv (idv mycomptype);
+create index on tidv (idv);
+explain (costs off)
+select a.idv, b.idv from tidv a, tidv b where a.idv = b.idv;
+                        QUERY PLAN                        
+----------------------------------------------------------
+ Merge Join
+   Merge Cond: (a.idv = b.idv)
+   ->  Index Only Scan using tidv_idv_idx on tidv a
+   ->  Materialize
+         ->  Index Only Scan using tidv_idv_idx on tidv b
+(5 rows)
+
+set enable_mergejoin = 0;
+explain (costs off)
+select a.idv, b.idv from tidv a, tidv b where a.idv = b.idv;
+                     QUERY PLAN                     
+----------------------------------------------------
+ Nested Loop
+   ->  Seq Scan on tidv a
+   ->  Index Only Scan using tidv_idv_idx on tidv b
+         Index Cond: (idv = a.idv)
+(4 rows)
+
+rollback;
+--
 -- test NULL behavior of whole-row Vars, per bug #5025
 --
 select t1.q2, count(t2.*)
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index 86c6d5be283..d3ba2a1c339 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -674,6 +674,26 @@ select * from a left join b on i = x and i = y and x = i;
 rollback;
 
 --
+-- test handling of merge clauses using record_ops
+--
+begin;
+
+create type mycomptype as (id int, v bigint);
+
+create temp table tidv (idv mycomptype);
+create index on tidv (idv);
+
+explain (costs off)
+select a.idv, b.idv from tidv a, tidv b where a.idv = b.idv;
+
+set enable_mergejoin = 0;
+
+explain (costs off)
+select a.idv, b.idv from tidv a, tidv b where a.idv = b.idv;
+
+rollback;
+
+--
 -- test NULL behavior of whole-row Vars, per bug #5025
 --
 select t1.q2, count(t2.*)