RE: 7.0.3(nofsync) vs 7.1

From: "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "'pgsql-hackers(at)postgresql(dot)org'" <pgsql-hackers(at)postgresql(dot)org>
Subject: RE: 7.0.3(nofsync) vs 7.1
Date: 2000-12-12 18:30:04
Message-ID: 8F4C99C66D04D4118F580090272A7A234D31F6@sectorbase1.sectorbase.com
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> >> What is the default commit delay now?
>
> > As before 5 * 10^(-6) sec - pretty the same as sleep(0) -:)
> > Seems CommitDelay is not very useful parameter now - XLogFlush
> > logic and fsync time add some delay.
>
> There was a thread recently about smarter ways to handle shared fsync
> of the log --- IIRC, we talked about self-tuning commit delay,
> releasing waiting processes as soon as someone else had fsync'd, etc.
> Looks like none of those ideas are in the code now. Did you not like
> any of those ideas, or just no time to work on it yet?

We're in beta - it's better to test WAL to find/fix bugs than make
further improvements.

Also, I've run test with 100 clients inserting records into 100 tables
(to minimize contentions) - 915 tps with fsync and 1190 tps without fsync.
So, we do ~ 18 commits per fsync now and probably we'll be able to
increase commit performance by ~ 30%, no more.

Vadim

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