Re: [BUG] Checkpointer on hot standby runs without looking checkpoint_segments - Mailing list pgsql-hackers

From Fujii Masao
Subject Re: [BUG] Checkpointer on hot standby runs without looking checkpoint_segments
Date
Msg-id CAHGQGwEP+bvZcCn1QMkK1z5zAy0NAv=5d9_aYtMh5LGsC_h-DA@mail.gmail.com
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In response to Re: [BUG] Checkpointer on hot standby runs without looking checkpoint_segments  (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>)
Responses Re: [BUG] Checkpointer on hot standby runs without looking checkpoint_segments
List pgsql-hackers
On Wed, Apr 18, 2012 at 10:22 AM, Kyotaro HORIGUCHI
<horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> I tried that at first. But I suppose the requirement here is 'if
> reading segments comes via replication stream, enable throttling
> by checkpoint_segments.' and WalRcvInProgress() seems fit to
> check that.

If so, what if replication is terminated and restarted repeatedly while
a restartpoint is running? It sometimes obeys and sometimes ignores
checkpoint_segments. Which seems strange behavior.

> Plus, adding SharedStartupStandbyMode into
> XLogCtlData seems accompanied with some annoyances which would
> not pay.

Hmm... what are you worried about? I don't think that sharing the variable
via XLogCtl is so difficult. Please see the code to share archiveCleanupCommand
from the startup process to the checkpointer. It looks very simple.

> By the way, do you have some advise about GetStandbyFlushRecPtr()
> and the order of the locations? I'm embarrassed with that...

Sorry. I could not parse this.... Could you explain this again?

Regards,

-- 
Fujii Masao


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