On Mon, Mar 16, 2009 at 10:57 AM, Brian Aker <[email protected]> wrote: > FYI (This was an internal reply I made, but I believe anyone on the list > would find it interesting). > > Begin forwarded message: > >> Hi! >> >> On Mar 16, 2009, at 1:29 AM, Jay Pipes wrote: >> >>> Frankly, libevent is being used entirely incorrectly in pool_of_threads >>> plugin... >> >> Yep! >> >> Though even in its current state if you are doing just primary key lookups >> it will outperform the threaded handler (spin up slap on the key test). The >> problem is that you need to be able to catch a IO event on a non-blocking >> port to make better use of it.
Jay, Can you give more details on the case where pool-of-threads makes anything faster? I have no problem making sysbench throughput 2X slower when pool-of-threads is used with MySQL 6.0. http://bugs.mysql.com/bug.php?id=42288 Did drizzle make significant changes to this when porting it? >> >> Though... the problem still exists that a port that continues to "block" >> will hold up any other transactions that will conflict. In the current state >> this is a bit worse then what it should be because we are not releasing to >> another sessions well enough (aka... we need to do this on IO event). Even >> fixing that though... this type of scheduler will only really work for cases >> were you have short transactions, or a large amount of read IO. In the end, >> libevent just gives us a scheduler for one particular type of IO. >> >> Long term? Some sort of scheduler that can grow or shrink... or possibly >> something where we can really do priority in the queries (aka... connect >> into the optimizer and use estimated cost). >> >> Cheers, >> -Brian > > -- > _______________________________________________________ > Brian "Krow" Aker, brian at tangent.org > Seattle, Washington > http://krow.net/ <-- Me > http://tangent.org/ <-- Software > _______________________________________________________ > You can't grep a dead tree. > > > > > _______________________________________________ > Mailing list: https://launchpad.net/~drizzle-discuss > Post to : [email protected] > Unsubscribe : https://launchpad.net/~drizzle-discuss > More help : https://help.launchpad.net/ListHelp > -- Mark Callaghan [email protected] _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
