… with the Anticipatory scheduler, however it should be even worse by design; Anticipatory should make Mysql wait even more on IO expecting sequential reads; while it will likely make random requests. Once you find the fastest scheduler…
Comment: kernel_mutex problem cont. Or triple your throughput
December 4, 2011 By 10 Comments
… low and when there are heavy batch jobs which are IO bound and would benefit from a lot higher innodb_thread… be to some form of IO aware thread scheduling for whole MySQL not just Innodb where you can schedule something else to run when thread is to be blocked on disk/network IO…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
… as not as I typically use these terms. For me IO is IO bound workload – disks are moving and CPU sits idle… easy to see if system is IO bound or CPU bound, while to understand if MySQL goes through more rows than it… to flush – it happens in the background on its own schedule. Such flush activity is another activity which will happen in…
Post: ext4 vs xfs on SSD
March 15, 2012 By 26 Comments
… MySQL 5.1 + InnoDB-plugin and later MySQL 5.5 (or equally Percona Server 5.1 and 5.5), InnoDB uses “asynchronous” IO… question I was asked, namely: “If MySQL 5.5 uses async IO, is innodb_write_io_threads still important?”, and it seems it…. I would still use value 2 or 4, to avoid scheduling overhead from single thread, but it does not seem critical…
Comment: MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
… issue, the issue is that the threads are not being scheduled on events. The framework in 6.0 never worked, all… was done. What happened? Dead-lock galore. I deleted that scheduler out of Drizzle before we went beta. Under load testing… this front. Anything MySQL derived has a long ways to go before it can achieve an event based IO/thread system like…
Post: Innodb Fuzzy checkpointing woes
May 10, 2006 By Leave a Comment
… this case many pages fall in the same LSN range scheduled for flush and Innodb might end up flushing most of… we can stop checkpoint kind flushes, which would avoid uneeded IO. One more related problem Innodb has – too many hard coded… how much disk IO system is loaded and compare it to constant. However the shared drive at shared MySQL virtual hosting…
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
… dump and reload large database and we had pretty good IO subsystem so we started number of mysqldump processes in parallel… Christoffer was doing (I was adviseor in this project from MySQL AB side) – to improve how Innodb read-ahead works by… need to stall unable to perform any quick IO and unable to progress until scheduled read ahead can be completed. Hopefully this…
Comment: Interesting MySQL and PostgreSQL Benchmarks
December 4, 2006 By 20 Comments
… help in fine-tuning mysql and solaris. We have years experience with mysql on linux and we had … increase in performance. Further we tried with different schedulers, some settings in /etc/System – which are already … memory, so we didnt have to keep the io system the same for all platforms, and if …
Comment: Living with backups
November 18, 2008 By 28 Comments
…* dd (Idle class) and MySQL (default class) to slow down to ridiculously low speed! – Using the deadline scheduler (which was the default) gives the best performance in all tested kernels – side read operation are fast and MySQL starts… faster than using deadline, and MySQL is lagging behind significantly more than using deadline. The IO subsystem is a hardware RAID 0…
Post: RAID System performance surprises
March 5, 2008 By 7 Comments
…MySQL database in 24/7 environments we typically hope for uniform… checks periodically. When it wakes up it will some IO resources (30% by default) which will affect your performance …have and see how they can be controlled – may be schedule them during least busy intervals or something similar. Also …
