Re: 7.0.3(nofsync) vs 7.1 - Mailing list pgsql-hackers

From Tom Lane
Subject Re: 7.0.3(nofsync) vs 7.1
Date
Msg-id 9578.976325543@sss.pgh.pa.us
Whole thread Raw
In response to RE: 7.0.3(nofsync) vs 7.1  ("Mikheev, Vadim" <vmikheev@SECTORBASE.COM>)
List pgsql-hackers
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM> writes:
> I have only one explanation: it reduces number of transactions ready
> to commit (because of the same FK writers will wait till first one
> committed - ie log fsynced) and WAL commit performance greatly depends
> on how many commits were done by single log fsync.
> 7.0.3+nofsync commit performance doesn't depend on this factor.

Sure, but that's not exactly a fair comparison is it?  7.0.3+nofsync
should be compared against 7.1+nofsync.  I put the pg_fsync routine
back in a little while ago, so nofsync should work again.

It occurs to me though that disabling fsync should probably also reduce
the WAL commit delay to zero, no?  What is the default commit delay now?
        regards, tom lane


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