QUERY PLAN                                           
-----------------------------------------------------------------------------------------------
 Aggregate  (cost=xxx rows=1 width=4)
   ->  Merge Join  (cost=xxx rows=100 width=4)
         Merge Cond: (bmt1.c1 = bmt2.c1)
         ->  Index Only Scan using t1_i1 on t1 bmt1  (cost=xxx rows=1000 width=4)
         ->  Sort  (cost=xxx rows=100 width=12)
               Sort Key: bmt2.c1
               ->  Hash Join  (cost=xxx rows=100 width=12)
                     Hash Cond: (bmt3.c1 = bmt2.c1)
                     ->  Hash Join  (cost=xxx rows=1100 width=8)
                           Hash Cond: (bmt3.c1 = bmt4.c1)
                           ->  Seq Scan on t3 bmt3  (cost=xxx rows=1100 width=4)
                           ->  Hash  (cost=xxx rows=1100 width=4)
                                 ->  Seq Scan on t4 bmt4  (cost=xxx rows=1100 width=4)
                     ->  Hash  (cost=xxx rows=100 width=4)
                           ->  Seq Scan on t2 bmt2  (cost=xxx rows=100 width=4)
(15 rows)

                                         QUERY PLAN                                         
--------------------------------------------------------------------------------------------
 Aggregate  (cost=xxx rows=1 width=4)
   ->  Nested Loop  (cost=xxx rows=1 width=4)
         Join Filter: (bmt2.c1 = bmt1.c1)
         ->  Nested Loop  (cost=xxx rows=1 width=12)
               ->  Hash Join  (cost=xxx rows=1 width=8)
                     Hash Cond: (bmt3.c1 = bmt4.c1)
                     ->  Seq Scan on t3 bmt3  (cost=xxx rows=1100 width=4)
                     ->  Hash  (cost=xxx rows=1100 width=4)
                           ->  Seq Scan on t4 bmt4  (cost=xxx rows=1100 width=4)
               ->  Index Only Scan using t2_i1 on t2 bmt2  (cost=xxx rows=1 width=4)
                     Index Cond: (c1 = bmt3.c1)
         ->  Index Only Scan using t1_i1 on t1 bmt1  (cost=xxx rows=1 width=4)
               Index Cond: (c1 = bmt3.c1)
(13 rows)