mifar07=# EXPLAIN ANALYZE SELECT id FROM ids WHERE id IN (SELECT id FROM object_t);
                                                           QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------
 Nested Loop IN Join  (cost=0.00..9851.68 rows=2140 width=4) (actual time=0.085..183.889 rows=1351 loops=1)
   ->  Seq Scan on ids  (cost=0.00..31.40 rows=2140 width=4) (actual time=0.014..24.032 rows=2009 loops=1)
   ->  Index Scan using object_t_pkey on object_t  (cost=0.00..4.58 rows=1 width=4) (actual time=0.071..0.071 rows=1 loops=2009)
         Index Cond: ("outer".id = object_t.id)
 Total runtime: 184.823 ms
(5 rows)

Time: 186.931 ms
mifar07=# EXPLAIN ANALYZE SELECT id FROM ids WHERE EXISTS (SELECT id FROM object_t o WHERE o.id = ids.id);
                                                             QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------
 Seq Scan on ids  (cost=0.00..9824.93 rows=1070 width=4) (actual time=0.086..165.053 rows=1351 loops=1)
   Filter: (subplan)
   SubPlan
     ->  Index Scan using object_t_pkey on object_t o  (cost=0.00..4.58 rows=1 width=4) (actual time=0.025..0.025 rows=1 loops=2009)
           Index Cond: (id = $0)
 Total runtime: 165.995 ms
(6 rows)

Time: 167.795 ms
mifar07=# EXPLAIN ANALYZE SELECT id FROM ids WHERE id NOT IN (SELECT id FROM object_t);
                                                        QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------
 Seq Scan on ids  (cost=36410.51..36447.26 rows=1070 width=4) (actual time=4168.247..4172.080 rows=658 loops=1)
   Filter: (NOT (hashed subplan))
   SubPlan
     ->  Seq Scan on object_t  (cost=0.00..34381.81 rows=811481 width=4) (actual time=0.044..2464.296 rows=811481 loops=1)
 Total runtime: 4210.784 ms
(5 rows)

Time: 4212.276 ms
mifar07=# EXPLAIN ANALYZE SELECT id FROM ids WHERE NOT EXISTS (SELECT id FROM object_t o WHERE o.id = ids.id);
                                                             QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------
 Seq Scan on ids  (cost=0.00..9824.93 rows=1070 width=4) (actual time=0.372..164.510 rows=658 loops=1)
   Filter: (NOT (subplan))
   SubPlan
     ->  Index Scan using object_t_pkey on object_t o  (cost=0.00..4.58 rows=1 width=4) (actual time=0.064..0.064 rows=1 loops=2009)
           Index Cond: (id = $0)
 Total runtime: 165.016 ms
(6 rows)

Time: 166.786 ms