Re: Checkpoint Tuning Question - Mailing list pgsql-general

From Dan Armbrust
Subject Re: Checkpoint Tuning Question
Date
Msg-id 82f04dc40907131353hde7a613x558c5125ce20d6ad@mail.gmail.com
Whole thread Raw
In response to Re: Checkpoint Tuning Question  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Checkpoint Tuning Question
Re: Checkpoint Tuning Question
Re: Checkpoint Tuning Question
List pgsql-general
> So this thought leads to a couple of other things Dan could test.
> First, see if turning off full_page_writes makes the hiccup go away.
> If so, we know the problem is in this area (though still not exactly
> which reason); if not we need another idea.  That's not a good permanent
> fix though, since it reduces crash safety.  The other knobs to
> experiment with are synchronous_commit and wal_sync_method.  If the
> stalls are due to commits waiting for additional xlog to get written,
> then async commit should stop them.  I'm not sure if changing
> wal_sync_method can help, but it'd be worth experimenting with.
>
>                        regards, tom lane
>


All of my testing to date has been done with synchronous_commit=off

I just tried setting full_page_writes=off - and like magic, the entire
hiccup went away.

Thanks,

Dan

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