On Fri, Jun 24, 2005 at 09:37:23AM -0400, Tom Lane wrote: > ITAGAKI Takahiro <[EMAIL PROTECTED]> writes: > > ... So I'll post the new results: > > > checkpoint_ | writeback | > > segments | cache | open_sync | fsync=false | O_DIRECT only | > > fsync_direct | open_direct > > ------------+-----------+-----------+---------------+---------------+---------------+-------------- > > [3] 3 | off | 38.2 tps | 138.8(+263.5%)| 38.6(+ 1.2%) | > > 38.5(+ 0.9%) | 38.5(+ 0.9%) > > Yeah, this is about what I was afraid of: if you're actually fsyncing > then you get at best one commit per disk revolution, and the negotiation > with the OS is down in the noise. > > At this point I'm inclined to reject the patch on the grounds that it > adds complexity and portability issues, without actually buying any > useful performance improvement. The write-cache-on numbers are not > going to be interesting to any serious user :-(
Is there anyone with a battery-backed RAID controller that could run these tests? I suspect that in that case the differences might be closer to 1 or 2 rather than 3, which would make the patch much more valuable. Josh, is this something that could be done in the performance lab? -- Jim C. Nasby, Database Consultant [EMAIL PROTECTED] Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?" ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])