Re: Error correction for n_dead_tuples

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: Error correction for n_dead_tuples
Date: 2007-09-26 08:23:20
Message-ID: 200709260823.l8Q8NKa05660@momjian.us
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This patch is no longer needed. We can revisit this during 8.4 to see
if it is still needed now that we have HOT.

---------------------------------------------------------------------------

ITAGAKI Takahiro wrote:
> Here is a patch discussed in
> http://archives.postgresql.org/pgsql-hackers/2007-02/msg00010.php
>
> Concurrent vacuum will save n_dead_tuples value at the beginning.
> Stats collector will be subtract the value from n_dead_tuples
> instead of setting it to zero. The statistics accuracy of n_dead_tuples
> will be better, especially just after finish of a vacuum.
>
> The behavior in VACUUM FULL is not changed because concurrent updates
> are not allowed during VACUUM FULL.
>
> Comments welcome.
>
> Regards,
> ---
> ITAGAKI Takahiro
> NTT Open Source Software Center

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Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
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