Re: [HACKERS] fsync method checking

Josh Berkus wrote:
> Tom, Bruce,
>
> > My previous point about checking different fsync spacings corresponds to
> > different assumptions about average transaction size. I think a useful
> > tool for determining wal_sync_method has got to be able to reflect that
> > range of possibilities.
>
> Questions:
> 1) This is an OSS project. Why not just recruit a bunch of people on
> PERFORMANCE and GENERAL to test the 4 different synch methods using real
> databases? No test like reality, I say ....

Well, I wrote the program to allow testing. I don't see a complex test
as being that much better than simple one. We don't need accurate
numbers. We just need to know if fsync or O_SYNC is faster.

>
> 2) Won't Jan's work on 7.5 memory and I/O management mean that we have to
> re-evaluate synching anyway?

No, it should not change sync issues.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073