Re: how much ram do i give postgres?
От | Scott Marlowe |
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Тема | Re: how much ram do i give postgres? |
Дата | |
Msg-id | 1098287545.21035.54.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: how much ram do i give postgres? (Josh Close <narshe@gmail.com>) |
Ответы |
Re: how much ram do i give postgres?
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Список | pgsql-general |
On Wed, 2004-10-20 at 07:25, Josh Close wrote: > It's slow due to several things happening all at once. There are a lot > of inserts and updates happening. There is periodically a bulk insert > of 500k - 1 mill rows happening. I'm doing a vacuum anaylyze every > hour due to the amount of transactions happening, and a vacuum full > every night. All this has caused selects to be very slow. At times, a > "select count(1)" from a table will take several mins. I don't think > selects would have to wait on locks by inserts/updates would it? 1: Is the bulk insert being done inside of a single transaction, or as individual inserts? 2: Are your fsm settings high enough for an hourly vacuum to be effective? 3: How selective is the where clause for your select (1) query? If there is no where clause or the where clause isn't very selective, then there will be a sequential scan every time. Since PostgreSQL has to hit the table after using an index anyway, if it's going to retrieve a fair percent of a table, it just goes right to a seq scan, which for postgresql, is the right thing to do. Post "explain analyze" of your slowest queries to the performance list if you can.
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