coverdb=# explain analyze SELECT id , title, artist, music, lyrics, year FROM search_song WHERE search_title IS NOT NULL  LIMIT 20 OFFSET 0 ;
                                                                       QUERY PLAN
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 Limit  (cost=0.00..0.41 rows=20 width=28) (actual time=1.52..6.54 rows=20 loops=1)
   ->  Subquery Scan search_song  (cost=0.00..134.93 rows=6593 width=28) (actual time=1.52..6.53 rows=21 loops=1)
         ->  Seq Scan on song r  (cost=0.00..134.93 rows=6593 width=28) (actual time=1.51..6.45 rows=21 loops=1)
               Filter: (title IS NOT NULL)
               SubPlan
                 ->  Aggregate  (cost=8.14..8.14 rows=1 width=25) (actual time=0.07..0.07 rows=1 loops=21)
                       ->  Nested Loop  (cost=0.00..8.14 rows=2 width=25) (actual time=0.02..0.03 rows=1 loops=21)
                             ->  Index Scan using credit_song_idx on credit c  (cost=0.00..3.08 rows=2 width=4) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: (song_id = $0)
                                   Filter: (type_id = 0)
                             ->  Index Scan using artist_pkey on artist a  (cost=0.00..3.02 rows=1 width=21) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: ("outer".artist_id = a.id)
                 ->  Aggregate  (cost=8.14..8.14 rows=1 width=25) (actual time=0.04..0.04 rows=1 loops=21)
                       ->  Nested Loop  (cost=0.00..8.14 rows=2 width=25) (actual time=0.02..0.02 rows=1 loops=21)
                             ->  Index Scan using credit_song_idx on credit c  (cost=0.00..3.08 rows=2 width=4) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: (song_id = $0)
                                   Filter: (type_id = 0)
                             ->  Index Scan using artist_pkey on artist a  (cost=0.00..3.02 rows=1 width=21) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: ("outer".artist_id = a.id)
                 ->  Aggregate  (cost=6.35..6.35 rows=1 width=25) (actual time=0.04..0.04 rows=1 loops=21)
                       ->  Nested Loop  (cost=0.00..6.35 rows=1 width=25) (actual time=0.01..0.02 rows=1 loops=21)
                             ->  Index Scan using credit_song_idx on credit c  (cost=0.00..3.08 rows=1 width=4) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: (song_id = $0)
                                   Filter: (type_id = 1)
                             ->  Index Scan using artist_pkey on artist a  (cost=0.00..3.02 rows=1 width=21) (actual time=0.01..0.01 rows=1 loops=15)
                                   Index Cond: ("outer".artist_id = a.id)
                 ->  Aggregate  (cost=6.35..6.35 rows=1 width=25) (actual time=0.03..0.03 rows=1 loops=21)
                       ->  Nested Loop  (cost=0.00..6.35 rows=1 width=25) (actual time=0.01..0.02 rows=1 loops=21)
                             ->  Index Scan using credit_song_idx on credit c  (cost=0.00..3.08 rows=1 width=4) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: (song_id = $0)
                                   Filter: (type_id = 1)
                             ->  Index Scan using artist_pkey on artist a  (cost=0.00..3.02 rows=1 width=21) (actual time=0.01..0.01 rows=1 loops=15)
                                   Index Cond: ("outer".artist_id = a.id)
                 ->  Aggregate  (cost=6.45..6.45 rows=1 width=25) (actual time=0.04..0.04 rows=1 loops=21)
                       ->  Nested Loop  (cost=0.00..6.45 rows=1 width=25) (actual time=0.01..0.02 rows=1 loops=21)
                             ->  Index Scan using credit_song_idx on credit c  (cost=0.00..3.08 rows=1 width=4) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: (song_id = $0)
                                   Filter: (type_id = 2)
                             ->  Index Scan using artist_pkey on artist a  (cost=0.00..3.02 rows=1 width=21) (actual time=0.01..0.01 rows=1 loops=14)
                                   Index Cond: ("outer".artist_id = a.id)
                 ->  Aggregate  (cost=6.45..6.45 rows=1 width=25) (actual time=0.03..0.03 rows=1 loops=21)
                       ->  Nested Loop  (cost=0.00..6.45 rows=1 width=25) (actual time=0.01..0.02 rows=1 loops=21)
                             ->  Index Scan using credit_song_idx on credit c  (cost=0.00..3.08 rows=1 width=4) (actual time=0.01..0.01 rows=1 loops=21)
                                   Index Cond: (song_id = $0)
                                   Filter: (type_id = 2)
                             ->  Index Scan using artist_pkey on artist a  (cost=0.00..3.02 rows=1 width=21) (actual time=0.01..0.01 rows=1 loops=14)
                                   Index Cond: ("outer".artist_id = a.id)
 Total runtime: 7.23 msec
(48 rows)