From: Michael Widenius Date: March 18 2009 2:23pm Subject: Re: [Maria-developers] Working on microsecond patches List-Archive: http://lists.mysql.com/maria/458 Message-Id: <18881.997.703247.618585@narttu.askmonty.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi! >>>>> "Vadim" == Vadim Tkachenko writes: Vadim> Michael, Vadim> Thread-pool should be used very carefully. Vadim> We tested it and InnoDB hangs in sysbench benchmarks when count of Vadim> client connection > size of thread-pool. Yes, this a problem when you have more locks than threads. The innodb deadlock detector has to timeout the hanged items. Vadim> The problem is transaction state. Some connections may do internals Vadim> locks and after that could not enter to pool, because all slots are busy. Vadim> I expect you will have the same problem with Maria when it can fully Vadim> support transactions. That is one of the main reasons I added --extra-port to MariaDB This allows you to connect and check/kill things if you get a hang. So things are not perfect now, but at least a little better. In the future we have to also look at creating more pool-threads when all pool-threads gets locked by a handler. Regards, Monty