a question for the way-back machine
От | Ben |
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Тема | a question for the way-back machine |
Дата | |
Msg-id | Pine.LNX.4.64.0612131259320.6762@localhost.localdomain обсуждение исходный текст |
Ответы |
Re: a question for the way-back machine
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Список | pgsql-general |
I'm using an ancient version of postgresql (7.3 - don't ask) and I'm experiencing a problem where many inserts into an empty table slow down over time, even if I analyze in the middle of the insertions. pg_stat_user_tables shows lots and lots of full scans, which explains the slowdown, but leads me to wonder why the full scans. Each insert is its own transaction. This table has at least one unique index on it, and a couple other multi-column indexes, so I was wondering if maybe that was what was causing the full scans. But a an explain shows that a select for that unique column will use the index, so now I'm wondering if maybe: - 7.3 isn't smart enough to use an index on an insert? Seems unlikely. - I have to start a new session to use new planner stats, even though each insert is in it's own transaction? Something I haven't verified for myself yet but have been told by others is that if I start these inserts quickly after installing a new database cluster (which probably translates as: before running "vacuum analyze" for the first time), then these slowdowns do not occur. I can't figure out why that might be. Any other thoughts?
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