Re: Allowing WAL fsync to be done via O_SYNC

[ Charset ISO-8859-1 unsupported, converting... ]
> > Based on the tests we did last week, it seems clear than on many
> > platforms it's a win to sync the WAL log by writing it with open()
> > option O_SYNC (or O_DSYNC where available) rather than 
> > issuing explicit fsync() (resp. fdatasync()) calls.
> 
> I don't remember big difference in using fsync or O_SYNC in tfsync
> tests. Both depend on block size and keeping in mind that fsync
> allows us syncing after writing *multiple* blocks I would either
> use fsync as default or don't deal with O_SYNC at all.

I see what you are saying.  That the OS may be faster at fsync'ing two
blocks in one operation rather than doing to O_SYNC operations.

Seems we should just pick a default and leave the rest for a later
release.  Marc wants RC1 tomorrow, I think.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026