Re: Too frequent checkpoints ?

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От Fujii Masao
Тема Re: Too frequent checkpoints ?
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Msg-id CAHGQGwEZQ2rpBjBg+6kptgQ7+CzdbmM=ig95MMqJoaHCFYfq6A@mail.gmail.com
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Ответ на Too frequent checkpoints ?  (Pavan Deolasee <pavan.deolasee@gmail.com>)
Ответы Re: Too frequent checkpoints ?  (Pavan Deolasee <pavan.deolasee@gmail.com>)
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On Fri, Feb 8, 2013 at 7:37 PM, Pavan Deolasee <pavan.deolasee@gmail.com> wrote:
> I wonder if this is all expected. The database is getting ZERO
> activity. There are no connections open at this time. The checkpoints
> are happening at every 30 seconds and new WAL files are being created,
> AFAIK because the old ones are getting archived. Can't we be smart
> about not archiving new files if we did not generate any new WAL since
> the last archive ?

AFAIR this problem has been discussed several times before, but has not
been fixed yet.

BTW, the cause of the problem is that the following sequences happens.

1. archive_timeout switches WAL file because checkpoint WAL record has   has been written since last switch
2. Checkpoint occurs and writes its WAL record because new WAL file was   generated since last checkpoint, i.e.,
checkpointthinks that
 
there is at least   some activity since last checkpoint.
3. Back to #1 after archive_timeout passed through.

Regards,

-- 
Fujii Masao



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