> > So seems we can use O_DSYNC without losing log write performance
> > comparing with write() + fsync. Though, we didn't tested write() +
> > fdatasync() yet...
> 
> Good point, we should check fdatasync() too --- although I have no
> machines where it's different from fsync().

I've tested it on Solaris - not better than O_DSYNC (expected, taking
in account that O_DSYNC results don't depend on block counts).

Ok, I've made changes in xlog.c and run tests: 50 clients inserted
(int4, text[1-256]) into 50 tables,
-B 16384, -wal_buffers 256, -wal_files 0.

FSYNC:        257tps
O_DSYNC:      333tps   

Just(?) 30% faster, -:(
But I had no ability to place log on separate disk, yet...

Vadim

Fri, 9 Mar 2001 20:15:14 -0800 
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
RE: AW: AW: AW: WAL does not recover gracefully from ou
	t-of -dis k-sp ace
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM> writes:
> Ok, I've made changes in xlog.c and run tests:

Could you send me your diffs?

			regards, tom lane

Fri, 09 Mar 2001 23:33:07 -0500
Tom Lane <tgl@sss.pgh.pa.us>
Re: AW: AW: AW: WAL does not recover gracefully from ou t-of -dis
	k-sp ace
> > Ok, I've made changes in xlog.c and run tests:
> 
> Could you send me your diffs?

Sorry, Monday only.

Vadim



Sat, 10 Mar 2001 23:24:19 -0800
"Vadim Mikheev" <vmikheev@sectorbase.com>
Re: AW: AW: AW: WAL does not recover gracefully from ou t-of -dis
	k-sp ace