TODO: Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options

Started by Joshua D. Drakeover 19 years ago4 messages
#1Joshua D. Drake
jd@commandprompt.com

Doesn't this exist in:

src/tools/fsync?

Do we just need to make it more user friendly?

Joshua D. Drake
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#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Joshua D. Drake (#1)
Re: TODO: Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options

"Joshua D. Drake" <jd@commandprompt.com> writes:

Doesn't this exist in:
src/tools/fsync?

No, that only tells you if the various alternatives *work*. Not which
one performs best.

regards, tom lane

#3Josh Berkus
josh@agliodbs.com
In reply to: Tom Lane (#2)
Re: TODO: Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options

Tom, JD,

No, that only tells you if the various alternatives *work*. Not which
one performs best.

"Performs best" is pretty elusive. On Solaris 10, for example, fdatasync
does best on pgbench on x86, but opendatasync does best on DBT2 on Sparc.
I'm not certain we can really determine this with any accuracy.

--
--Josh

Josh Berkus
PostgreSQL @ Sun
San Francisco

#4Tom Lane
tgl@sss.pgh.pa.us
In reply to: Josh Berkus (#3)
Re: TODO: Determine optimal fdatasync/fsync, O_SYNC/O_DSYNC options

Josh Berkus <josh@agliodbs.com> writes:

"Performs best" is pretty elusive. On Solaris 10, for example, fdatasync
does best on pgbench on x86, but opendatasync does best on DBT2 on Sparc.
I'm not certain we can really determine this with any accuracy.

Yeah, if it were easy we've have done it already :-(. One thing that
would be useful though is to try to gather datapoints like the above
for a range of different operating systems. Even if we could tell
people "here are the two or three settings worth trying for your OS",
we'd be ahead of the game.

regards, tom lane