Re: [HACKERS] Why is that so slow?

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От Bruce Momjian
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?
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)
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