Re: pg_autovacuum vacuum cost variables patch
От | Michael Paesold |
---|---|
Тема | Re: pg_autovacuum vacuum cost variables patch |
Дата | |
Msg-id | 008901c4bb49$dc515160$ad01a8c0@zaphod обсуждение исходный текст |
Ответ на | pg_autovacuum vacuum cost variables patch ("Matthew T. O'Connor" <matthew@zeut.net>) |
Ответы |
Re: pg_autovacuum vacuum cost variables patch
Re: pg_autovacuum vacuum cost variables patch |
Список | pgsql-patches |
Matthew T. O'Connor wrote: > Two questions: > 1) It is my understanding that these new GUC vars only effect vacuum. > That is they do NOT have any effect on an analyze command right? (I ask > since I'm only setting the vars before I issue a vacuum command) No, vacuum also affects analyze alone (cvs tip here): (2.5 seconds -> 50 seconds) test=# SET vacuum_cost_delay TO 0; SET Time: 0.308 ms test=# analyze; ANALYZE Time: 2591.259 ms test=# SET vacuum_cost_delay TO 10; SET Time: 0.309 ms test=# analyze; ANALYZE Time: 51737.896 ms And it seems it affects analyze much more than vacuum, at least if there is *nothing* to vacuum... (2 seconds -> 8 seconds) test=# SET vacuum_cost_delay TO 0; SET Time: 0.261 ms test=# VACUUM; VACUUM Time: 1973.137 ms test=# SET vacuum_cost_delay TO 10; SET Time: 0.236 ms test=# vacuum; VACUUM Time: 7966.085 ms I suggest you also issue the SET commands for analyze also. ISTM that there is also no distinction between VACUUM and VACUUM FULL, but I think pg_autovacuum never does a vacuum full, so there is no problem with that. Best Regards, Michael Paesold
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