Re: [HACKERS] Re: vacuum timings
От | Bruce Momjian |
---|---|
Тема | Re: [HACKERS] Re: vacuum timings |
Дата | |
Msg-id | 200001221733.MAA21558@candle.pha.pa.us обсуждение исходный текст |
Ответ на | RE: [HACKERS] Re: vacuum timings ("Hiroshi Inoue" <Inoue@tpf.co.jp>) |
Список | pgsql-hackers |
> > Quite a few people have reported finding the opposite in practice. > > You should probably try vacuuming after deleting or updating some > > fraction of the rows, rather than just the all or none cases. > > > > Vacuum after delelting all rows isn't a worst case. > There's no moving in that case and vacuum doesn't need to call > index_insert() corresponding to the moving of heap tuples. > > Vacuum after deleting half of rows may be one of the worst case. > In this case,index_delete() is called as many times as 'delete all' > case and expensive index_insert() is called for moved_in tuples. I will test that. -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania19026
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