Re: Memory usage during vacuum
От | Shelby Cain |
---|---|
Тема | Re: Memory usage during vacuum |
Дата | |
Msg-id | 20040325184928.46721.qmail@web41613.mail.yahoo.com обсуждение исходный текст |
Ответ на | Re: Memory usage during vacuum (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-general |
I had thought that I had dropped and reloaded this table but apparently I hadn't and I had set the statistics target for one column to 500 while experimenting. Resetting it to -1 and running with a default of 300 gets ~ 70 megs memory footprint during the analyze now. Thanks Tom for indulging my curiosity on the matter. I've learned something that I didn't readily pick up from reading the documentation. Regards, Shelby Cain --- Tom Lane <tgl@sss.pgh.pa.us> wrote: > Shelby Cain <alyandon@yahoo.com> writes: > > It still decided to sample 150000 rows. Am I > missing > > something obvious here? Shouldn't fewer rows be > > sampled when I set the collection target to 1? > > The sample size is 300 rows times the largest > per-column analysis > target, where default_statistics_target is used if > the recorded > per-column setting is -1. I would say that you have > set a target of 500 > for at least one of the columns of that table, using > ALTER TABLE SET > STATISTICS. Try this to see which: > > select attname, attstattarget from pg_attribute > where attrelid = 'table_name_here'::regclass; > > regards, tom lane __________________________________ Do you Yahoo!? Yahoo! Finance Tax Center - File online. File on time. http://taxes.yahoo.com/filing.html
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