Re: [dspam-users] Postgres vs. MySQL
От | Lionel Bouton |
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Тема | Re: [dspam-users] Postgres vs. MySQL |
Дата | |
Msg-id | 41A85386.8070407@bouton.name обсуждение исходный текст |
Ответ на | Re: [dspam-users] Postgres vs. MySQL ("Casey Allen Shobe" <cshobe@osss.net>) |
Список | pgsql-performance |
Casey Allen Shobe wrote the following on 11/27/04 03:11 : >I posted about this a couple days ago on dspam-dev... > >I am using DSpam with PostgreSQL, and like you discovered the horrible >performance. The reason is because the default PostgreSQL query planner >settings determine that a sequence scan will be more efficient than an >index scan, which is wrong. To correct this behavior, adjust the query >planner settings for the appropriate table/column with this command: > >alter table "dspam_token_data" alter "token" set statistics 200; analyze; > >Let me know if it help you. It worked wonders for me. > > > In tum mode, this could help too (I'm currently testing it) : CREATE INDEX id_token_data_sumhits ON dspam_token_data ((spam_hits + innocent_hits)); Indeed each UPDATE on dspam_token_data in TUM is done with : WHERE ... AND spam_hits + innocent_hits < 50
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