Re: Impact of foreign keys on a simple count(*) ?
От | C. Bensend |
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Тема | Re: Impact of foreign keys on a simple count(*) ? |
Дата | |
Msg-id | 50512.63.227.74.41.1097295204.squirrel@63.227.74.41 обсуждение исходный текст |
Ответ на | Re: Impact of foreign keys on a simple count(*) ? (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-sql |
> Foreign keys have zero, nada, zilch to do with the performance of > count(*). OK, I just wanted to make sure. > The only plausible theory I can think of for the performance > difference is that in your "new" database the table has been through > several mass updates, leading to a whole lot of dead rows and a much > larger physical table size to scan through. I'd suggest a VACUUM > VERBOSE on both old and new copies of the table to get an idea of the > relative physical sizes. You might need a VACUUM FULL to get the new > table back down to a reasonable size... Oh good lord. *waves the Idiot Flag as he slinks back under his rock* Thank you, Tom, for your patience. That was it. I'm a potatohead, but I'm learning. :) Benny, swearing he DID do a vacuum, but obviously not... -- "Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes." -- .sig on Slashdot
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