Re: Improvement of checkpoint IO scheduler for stable transaction responses

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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