help with understanding EXPLAIN

Hello

I have an application hosted on Heroku. They use postgres. It's more or less
abstracted away, but I can get some performance data from New Relic. For the
most part, performance is ok, but now and then some queries take a few
seconds, and spike up to 15 or even 16 seconds! Ouch!

This is the most detailed information I could get form New Relic. Do you
have any suggestions how I could improve the performance?

QUERY PLANLimit (cost=26.49..1893.46 rows=1 width=4) QUERY PLAN -> Unique
(cost=26.49..44833.82 rows=24 width=4) QUERY PLAN -> Nested Loop
(cost=26.49..44833.81 rows=24 width=4) QUERY PLAN -> Merge Join
(cost=26.49..44532.99 rows=4773 width=8) QUERY PLAN Merge Cond: (songs.id =
artists_songs.song_id) QUERY PLAN -> Index Scan using songs_pkey on songs
(cost=0.00..25219.30 rows=4773 width=4) QUERY PLAN Filter:
(lower((name)::text) = 'thirteen'::text) QUERY PLAN -> Index Scan using
index_artists_songs_on_song_id on artists_songs (cost=0.00..18822.04
rows=960465 width=8) QUERY PLAN -> Index Scan using artists_pkey on artists
(cost=0.00..0.06 rows=1 width=4) QUERY PLAN Index Cond: (artists.id =
artists_songs.artist_id) QUERY PLAN Filter: (lower((artists.name)::text) =
'red mountain church'::text)

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Brandon Casci
Loudcaster
http://loudcaster.com
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