Re: Improvement of checkpoint IO scheduler for stable transaction responses - Mailing list pgsql-hackers

From Joshua D. Drake
Subject Re: Improvement of checkpoint IO scheduler for stable transaction responses
Date
Msg-id 51D59644.2070005@commandprompt.com
Whole thread Raw
In response to Re: Improvement of checkpoint IO scheduler for stable transaction responses  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: Improvement of checkpoint IO scheduler for stable transaction responses
List pgsql-hackers
On 07/04/2013 06:05 AM, Andres Freund wrote:

>>> Presumably the smaller segsize is better because we don't
>>> completely stall the system by submitting up to 1GB of io at once. So,
>>> if we were to do it in 32MB chunks and then do a final fsync()
>>> afterwards we might get most of the benefits.
>> Yes, I try to test this setting './configure --with-segsize=0.03125' tonight.
>> I will send you this test result tomorrow.
>

I did testing on this a few years ago, I tried with 2MB segments over 
16MB thinking similarly to you. It failed miserably, performance 
completely tanked.

JD

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