QUERY PLAN                                 
---------------------------------------------------------------------------
 Merge Join  (cost=xxx rows=100 width=19)
   Merge Cond: (t1.c1 = t2.c1)
   ->  Index Scan using t1_i1 on t1  (cost=xxx rows=1000 width=15)
   ->  Sort  (cost=xxx rows=100 width=4)
         Sort Key: t2.c1
         ->  Seq Scan on t2  (cost=xxx rows=100 width=4)
(6 rows)

                                QUERY PLAN                                 
---------------------------------------------------------------------------
 Merge Join  (cost=xxx rows=100 width=19)
   Merge Cond: (t1.c1 = t2.c1)
   ->  Index Scan using t1_i1 on t1  (cost=xxx rows=1000 width=15)
   ->  Sort  (cost=xxx rows=100 width=4)
         Sort Key: t2.c1
         ->  Seq Scan on t2  (cost=xxx rows=100 width=4)
(6 rows)

                                QUERY PLAN                                 
---------------------------------------------------------------------------
 Merge Join  (cost=xxx rows=1 width=19)
   Merge Cond: (t1.c1 = t2.c1)
   ->  Index Scan using t1_i1 on t1  (cost=xxx rows=1000 width=15)
   ->  Sort  (cost=xxx rows=100 width=4)
         Sort Key: t2.c1
         ->  Seq Scan on t2  (cost=xxx rows=100 width=4)
(6 rows)