Re: [HACKERS] Why is that so slow?
От | Bruce Momjian |
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Тема | Re: [HACKERS] Why is that so slow? |
Дата | |
Msg-id | 199903071127.GAA15132@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [HACKERS] Why is that so slow? (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: [HACKERS] Why is that so slow?
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Список | pgsql-hackers |
> Tatsuo Ishii <t-ishii@sra.co.jp> writes: > >> Something is fishy here. Have you done a "vacuum analyze" since loading > >> the data in these tables? > > > Oh, I never thought about that. > > Ah. OK, that explains the system's poor choice of plan --- it was > effectively operating on the assumption that these tables were small. > > (Note to hackers: maybe a freshly created table should be given dummy > statistics, say having 1000 rows instead of 0 rows? That would help > to prevent the optimizer from making really foolish choices when no > vacuum's been done yet for the table. But I dunno whether we could > invent plausible default values for all the stats...) No way to really make a default. Zero is the correct number when the table is created, right? Improved optimize may be even worse or better for un-analyzed tables. -- Bruce Momjian | http://www.op.net/~candle maillist@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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