Re: Need help with 8.4 Performance Testing - Mailing list pgsql-performance

From Robert Haas
Subject Re: Need help with 8.4 Performance Testing
Date
Msg-id 603c8f070812091458w14021741s61996a27e94f1c82@mail.gmail.com
Whole thread Raw
In response to Re: Need help with 8.4 Performance Testing  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Need help with 8.4 Performance Testing  (Ben Chobot <bench@silentmedia.com>)
Re: Need help with 8.4 Performance Testing  (Scott Carey <scott@richrelevance.com>)
List pgsql-performance
> Hmm ... I wonder whether this means that the current work on
> parallelizing I/O (the posix_fadvise patch in particular) is a dead
> end.  Because what that is basically going to do is expend more CPU
> to improve I/O efficiency.  If you believe this thesis then that's
> not the road we want to go down.

I don't believe the thesis.  The gap between disk speeds and memory
speeds may narrow over time, but I doubt it's likely to disappear
altogether any time soon, and certainly not for all users.

Besides which, I believe the CPU overhead of that patch is pretty darn
small when the feature is not enabled.

...Robert

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