On Tue, 27 Nov 2007, Scott Ribe wrote:
IIRC, it was later established that during those tests they had fsync enabled on OS X and disabled on Linux.
You recall correctly but I'm guessing you didn't keep up with the investigation there; I was tempted to bring this up in that last message but was already running too long.
Presumably you're talking about http://ridiculousfish.com/blog/?p=17 . The fsync theory was suggested by them and possibly others after Anandtech's first benchmarking test of this type.
The second test that I linked to rebutted that at http://www.anandtech.com/mac/showdoc.aspx?i=2520&p=6 . This specific issue is also addressed by a comment from Johan Of Anandtech on the ridiculousfish site. The short version is that the MySQL they were using had a MyISAM configuration that doesn't do fsyncs, period, so it's impossible fsyncs were to blame. You only get fsync if you're running InnoDB. I think the reason for this confusion is that at the time of the initial review, working MySQL fsync under OS X was pretty new (January 2005 I think, http://dev.mysql.com/doc/refman/4.1/en/news-4-1-9.html )
Ultimately, the exact cause here doesn't change how to clear the air here. As I suggested, the only way to refute benchmarks showing awful performance is not to theorize as to the cause, but to show new ones that disprove the first ones are still accurate. If you can point me to one of those, I'd love to see it--this is actually one of the items on the relatively short list of why I'm typing this on a Thinkpad running Linux instead of a Macbook (the other big one is Apple's string of Eclipse issues, which I already ranted about recently at http://slashdot.org/comments.pl?sid=342667&cid=21154137 )
-- * Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
