Re: "Slow" query or just "Bad hardware"?
| От | PFC |
|---|---|
| Тема | Re: "Slow" query or just "Bad hardware"? |
| Дата | |
| Msg-id | op.t8opdgzscigqcu@apollo13.peufeu.com обсуждение исходный текст |
| Ответ на | "Slow" query or just "Bad hardware"? ("Jesper Krogh" <jesper@krogh.cc>) |
| Ответы |
Re: "Slow" query or just "Bad hardware"?
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| Список | pgsql-performance |
Also, sometimes offine TOASTing is evil : Say you have a forum, you want the posts table to be CLUSTER'ed on (topic_id, post_id) so displaying 1 page with 30 posts on it uses 1 seek, not 30 seeks. But CLUSTER doesn't touch the data that has been pushed offline in the toast table. So, in that case, it can pay (big time actually) to disable toasting, store the data inline, and benefit from cluster. So basically : Data that is seldom used or used only in queries returning/examining 1 row bu otherwise eats cache -> push it away (toast or partition) Data that is used very often in queries that return/examine lots of rows, especially if said rows are in sequence (cluster...) -> keep it inline
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