On 24 June 2010 09:52, kaifeng.zhu <cafeeee@xxxxxxxxx> wrote: > Hi All, > > I have a table named emails which created by following script: > create table emails ( > email_id bigserial primary key, > email_msg_id char(36) not null, > email_sender text not null) > > The table has more than 10 million of records and I have already > created indexes on email_msg_id and email_sender > > Following script finished very quickly (less than 1 seconds): > select * from emails where email_msg_id = > '4dba381b-f55e-02d3-4b4a-95e2e98178e2' limit 1 > But a similar script cost more than ten seconds: > select * from emails where email_msg_id = > '4dba381b-f55e-02d3-4b4a-95e2e98178e2' and email_sender_text = > 'sender@xxxxxxxxxx' limit 1 > > Both those scripts returns 0 rows of records indeed. > > Any comment are highly appreciated. > Sounds like the planner took a wrong turn in the 2nd case. Which version of PostgreSQL are you running? Thom -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
