explain select * from big join low on b=l order by b;
                                  QUERY PLAN                                  
------------------------------------------------------------------------------
 Merge Join  (cost=0.00..89.31 rows=1000 width=8)
   Merge Cond: (big.b = low.l)
   ->  Index Scan using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan using lowi on low  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join low on b=l order by b desc;
                                      QUERY PLAN                                       
---------------------------------------------------------------------------------------
 Merge Join  (cost=3266.70..3356.01 rows=1000 width=8)
   Merge Cond: (big.b = low.l)
   ->  Index Scan Backward using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan Backward using lowi on low  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join lowp on b=l order by b;
                                  QUERY PLAN                                  
------------------------------------------------------------------------------
 Merge Join  (cost=306.00..395.48 rows=1000 width=8)
   Merge Cond: (big.b = lowp.l)
   ->  Index Scan using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan using lowpi on lowp  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join lowp on b=l order by b desc;
                                      QUERY PLAN                                       
---------------------------------------------------------------------------------------
 Merge Join  (cost=2960.53..3050.01 rows=1000 width=8)
   Merge Cond: (big.b = lowp.l)
   ->  Index Scan Backward using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan Backward using lowpi on lowp  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join highm on b=h order by b;
                                  QUERY PLAN                                  
------------------------------------------------------------------------------
 Merge Join  (cost=2968.49..3057.34 rows=1000 width=8)
   Merge Cond: (big.b = highm.h)
   ->  Index Scan using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan using highmi on highm  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join highm on b=h order by b desc;
                                      QUERY PLAN                                       
---------------------------------------------------------------------------------------
 Merge Join  (cost=298.67..387.53 rows=1000 width=8)
   Merge Cond: (big.b = highm.h)
   ->  Index Scan Backward using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan Backward using highmi on highm  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join high on b=h order by b;
                                  QUERY PLAN                                  
------------------------------------------------------------------------------
 Merge Join  (cost=3267.82..3355.97 rows=1000 width=8)
   Merge Cond: (big.b = high.h)
   ->  Index Scan using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan using highi on high  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)

explain select * from big join high on b=h order by b desc;
                                      QUERY PLAN                                       
---------------------------------------------------------------------------------------
 Merge Join  (cost=0.05..88.19 rows=1000 width=8)
   Merge Cond: (big.b = high.h)
   ->  Index Scan Backward using bigi on big  (cost=0.00..3050.26 rows=100000 width=4)
   ->  Index Scan Backward using highi on high  (cost=0.00..43.25 rows=1000 width=4)
(4 rows)