Message-ID: <53FD7DCC.5020005@vmware.com>
Date: Wed, 27 Aug 2014 09:42:20 +0300
From: Heikki Linnakangas <hlinnakangas@vmware.com>
Organization: VMware
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To: Jeff Davis <pgsql@j-davis.com>
CC: Greg Stark <stark@mit.edu>, Robert Haas <robertmhaas@gmail.com>, "Andres
 Freund" <andres@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>,
 Bruce Momjian <bruce@momjian.us>, Rajeev rastogi <rajeev.rastogi@huawei.com>,
 Ants Aasma <ants@cybertec.at>, PostgreSQL-development
 <pgsql-hackers@postgresql.org>, Markus Wanner <markus@bluegap.ch>
Subject: Re: Proposal for CSN based snapshots
References: <51B6C97B.1070000@bluegap.ch>		
 <BF2827DCCE55594C8D7A8F7FFD3AB7713DDBC758@SZXEML508-MBX.china.huawei.com>		
 <5370D323.1070606@vmware.com> <20140512144112.GB9619@awork2.anarazel.de>		
 <5370E267.2020904@vmware.com> <20140515183436.GD25053@momjian.us>		
 <CA+TgmoYiqga4KWz_1=O8D6ivmTAJfY=-fxO6Nk+D-o3M0M60=Q@mail.gmail.com>		
 <20140515200632.GB16014@awork2.anarazel.de>		
 <20140515213714.GB7857@eldon.alvh.no-ip.org> <53889CCB.7030005@vmware.com>		
 <20140530152721.GC30516@awork2.anarazel.de> <5388D02D.6040305@vmware.com>		
 <CA+TgmoZ4cP_1Pavwn+VX74_ksDhHf-whO5FFR1j+NdZqONu8MA@mail.gmail.com>		
 <CAM-w4HMG-YeTfWc3r_excej3Kd04q4zDDXR0hxShVbij211ABA@mail.gmail.com>		
 <539AD153.9000004@vmware.com> <1409043789.2335.330.camel@jeff-desktop>	
 <53FC6545.7000501@vmware.com> <1409116988.2335.463.camel@jeff-desktop>
 <53FD7D65.9040602@vmware.com>
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On 08/27/2014 09:40 AM, Heikki Linnakangas wrote:
> On 08/27/2014 08:23 AM, Jeff Davis wrote:
>> On Tue, 2014-08-26 at 13:45 +0300, Heikki Linnakangas wrote:
>>> Yeah. This patch in the current state is likely much much slower than
>>> unpatched master, except in extreme cases where you have thousands of
>>> connections and short transactions so that without the patch, you spend
>>> most of the time acquiring snapshots.
>>
>> What else are you looking to accomplish with this patch during this
>> 'fest? Bug finding? Design review? Performance testing?
>
> Design review, mostly. I know the performance still sucks. Although if
> you can foresee some performance problems, aside from the extra CSNLOG
> lookups, it would be good to know.

I think for this commitfest, I've gotten as much review of this patch 
that I can hope for. Marking as "Returned with Feedback". But of course, 
feel free to continue reviewing and commenting ;-).

- Heikki


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