On Mon, 13 Oct 2008, Mikkel Høgh wrote:
Well, in that benchmark, what you say is only true for the Niagara processors. On the Opteron page, MySQL performance only drops slightly as concurrency passes 50.
That's partly because the upper limit on the graph only goes to 100 concurrent processes. Since the Opterons are faster, that's not a broad enough scale to see how fast the right edge of the MySQL curve falls.
You are right that the Niagara processors have a sharper decline than the more traditional platforms. The MySQL 5.0.20a graphs at http://tweakers.net/reviews/657/6 has a nice comparison graph showing a few different architectures that's also interesting.
Anyway, you don't actually have to believe any of this; you've got a testbed to try for yourself if you just crank the user count up. The main thing I was trying to suggest is that MySQL being a bit faster at 5 users is not unusual, but it's not really representative of which performs better either.
In general, MySQL seems to have problems with some kinds of threading, since their perfomance on Mac OS X is crappy as well for that reason.
One of the reasons (but by no means not the only one) that PostgreSQL uses a multi-process based architecture instead of a threaded one is because thread library quality varies so much between platforms.
-- * Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
