Subject: Re: Proposal for CSN based snapshots
To: Stephen Frost <sfrost@snowman.net>
References: 
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Cc: Robert Haas <robertmhaas@gmail.com>, Heikki Linnakangas
 <hlinnaka@iki.fi>, Tom Lane <tgl@sss.pgh.pa.us>,
 Alexander Korotkov <a.korotkov@postgrespro.ru>,
 Simon Riggs <simon@2ndquadrant.com>, Dilip Kumar <dilipbalaut@gmail.com>,
 Jeff Davis <pgsql@j-davis.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>,
 Alvaro Herrera <alvherre@2ndquadrant.com>, Greg Stark <stark@mit.edu>,
 Andres Freund <andres@2ndquadrant.com>,
 Rajeev rastogi <rajeev.rastogi@huawei.com>, Markus Wanner
 <markus@bluegap.ch>, Ants Aasma <ants@cybertec.at>,
 Bruce Momjian <bruce@momjian.us>, obartunov <obartunov@postgrespro.ru>,
 Teodor Sigaev <teodor@postgrespro.ru>
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
Message-ID: <75c0ea70-6292-6b24-ac8f-cea21134f8d8@commandprompt.com>
Date: Wed, 10 Aug 2016 09:24:22 -0700
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On 08/10/2016 09:04 AM, Stephen Frost wrote:
> * Joshua D. Drake (jd@commandprompt.com) wrote:
>> +1 for Robert here, removing async commit is a non-starter. It is
>> PostgreSQL performance 101 that you disable synchronous commit
>> unless you have a specific data/business requirement that needs it.
>> Specifically because of how much faster Pg is with async commit.
>
> I agree that we don't want to get rid of async commit, but, for the
> archive, I wouldn't recommend using it unless you specifically understand
> and accept that trade-off, so I wouldn't lump it into a "PostgreSQL
> performance 101" group- that's increasing work_mem, shared_buffers, WAL
> size, etc.  Accepting that you're going to lose *committed* transactions
> on a crash requires careful thought and consideration of what you're
> going to do when that happens, not the other way around.

Yes Stephen, you are correct which is why I said, "unless you have a 
specific data/business requirement that needs it".

Thanks!

jD

>
> Thanks!
>
> Stephen
>


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