On Thu, Mar 07, 2002 at 09:57:54AM -0700, Sasha Pachev wrote: > On Thursday 07 March 2002 12:42 am, Jeremy Zawodny wrote: > > > > Do you have any feel for how much slower a debugging version of > > MySQL is compared to a normal version? ?I ask because my > > replication heartbeat monitor has noticed this particular slave > > falling behind on replication a fair amount. ?It usually doesn't > > get too far behind, but it's certainly farther behind that it's > > neighbor--which has a slower CPU. > > Depends on the queries. I would say it could be from 3 to 10 times > slower. To know for sure, use BUILD/compile-pentium instead of > BUILD/compile-pentium-debug. This will compile a perfectly optimal > binary.
Okay, it's not a big deal. I was going to just run the debug binary in case things go wrong and you need more detail. > > And could that fact have anything to do with SHOW SLAVE STATUS being > > slow sometimes? > > I've figured out what's up with this one, I think. SHOW SLAVE STATUS > needs to acquire a simultaneous lock on the I/O thread and on the > SQL thread, and it might be a while before both of them will > surrender that lock if they are busy. I have been rather > conservative and very possibly made the critical region wider that > what it should be. Ah, makes sense. Better safe than sorry. :-) > I think part of the problem is also in the FreeBSD mutex > implementation - the current holder of the mutex surrenders it for > only a very short time and it is possible that there could be some > starvation issues. I woder if FreeBSD has different mutex types - in > this case, we want the kind that puts fairness above speed. Right. I'll ask some of the FreeBSD folks here when I get a chance. Thanks! Jeremy -- Jeremy D. Zawodny, <[EMAIL PROTECTED]> Technical Yahoo - Yahoo Finance Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936 MySQL 3.23.47-max: up 28 days, processed 989,034,558 queries (407/sec. avg) --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
