Re: PostgreSQL Gotchas --- count()

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От Bruce Momjian
Тема Re: PostgreSQL Gotchas --- count()
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Msg-id 200510070214.j972Eej26805@candle.pha.pa.us
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Ответ на Re: PostgreSQL Gotchas --- count()  ("Gregory S. Williamson" <gsw@globexplorer.com>)
Ответы Re: PostgreSQL Gotchas --- count()  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-general
Gregory S. Williamson wrote:
> On Informix however it is blindingly fast, and can also be instantly
> conjured with the dbaccess tool (Info/Table/Status). They might be
> stashing this count somewhere, but it is not available when the table
> is locked, as during a load. However they do it, performance does not
> seem to suffer, and having this rapidly available is certainly nice.
> Especially when people are used to it.
>

Informix locks rows during modification so they don't have the MVCC
visibility problem we have (some rows are visible to only some
backends).

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