2 rows expected on a primary key
От | Gaetano Mendola |
---|---|
Тема | 2 rows expected on a primary key |
Дата | |
Msg-id | 423971F2.3050701@bigfoot.com обсуждение исходный текст |
Список | pgsql-performance |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi all, I'm running a 7.4.x engine and I'm seeing in a explain analyze: - -> Hash (cost=4.00..4.00 rows=2 width=16) (actual time=30.542..30.542 rows=0 loops=1) -> Index Scan using user_login_login_key on user_login ul (cost=0.00..4.00 rows=2 width=16) (actual time=30.482..30.490rows=1 loops=1) Index Cond: ((login)::text = 'Zoneon'::text) why postgres perform an extimation of 2 rows knowing that column it's a primary key ? If I do an explain analyze directly on the table I get: # explain analyze select * from user_login where login = 'Zoneon'; QUERY PLAN - ---------------------------------------------------------------------------------------------------------------------------------- Index Scan using user_login_login_key on user_login (cost=0.00..4.00 rows=1 width=16) (actual time=0.050..0.052 rows=1loops=1) Index Cond: ((login)::text = 'Zoneon'::text) Total runtime: 4.627 ms (3 rows) btw, is it normal that cast ? Regards Gaetano Mendola -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (MingW32) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFCOXHy7UpzwH2SGd4RAgwAAJ9SMJ3OfYjv03IhhTbJ9GSLby4nfwCg5ezu UOH8wXRsNAvWRni7GSKlMps= =6yFm -----END PGP SIGNATURE-----
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