… Linux it is number of processes which are in “running” state or in “uninterruptable sleep” state which typically corresponds to disk IO… and performance still poor because application is not parallel enough. Similar situations can happen if there is a lot of network IO… the box it will perform well as soon as you need to do a lot of queuing performance starts to suffer. Let…
Post: Performance impact of complex queries
January 17, 2007 By 11 Comments
What is often underestimated is impact of MySQL Performance by complex queries on large data sets(ie some large … for directory with couple of files. In recent Linux Kernels deadline or cfq IO schedulers should be better with this. So what… suffer from table locks reporting queries can affect web site performance dramatically. Sometimes instead of using slave you may use database…
Post: Is there room for more MySQL IO Optimization?
January 3, 2013 By 11 Comments
….05 System | Supermicro; PDSMi; v0123456789 (Other) Service Tag | 0123456789 Platform | Linux Release | Ubuntu 12.04.1 LTS (precise) Kernel | 3.2… very close numbers for buffered and unbuffered IO for read only workloads, if anything unbuffered performance should be better as it has… is dramatically different. The good news though is even though performance advantages of buffered mode can be dramatic for some workloads…
Post: Innodb Performance Optimization Basics
November 1, 2007 By 75 Comments
… of Hardware OS And Application optimization. I call this Innodb Performance Optimization Basics so these are general guidelines which work well… – run 64bit operating system. We still see people running 32bit Linux on 64bit capable boxes with plenty of memory. Do not… setting improves performance. Though be careful if you do not have battery backed up RAID cache as when write IO may suffer…
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…_ | /mnt/nfs/dist/mysql-5.6.10-linux-glibc2. | | PERFORMANCE_SCHEMA_MAX_COND_INSTANCES | 1000 | 836 | | PERFORMANCE_SCHEMA_MAX_MUTEX_INSTANCES | 1000000 | 3282… but will increase potential starvation of queued threads especially for IO bound workloads. Most users will not be affected though as…
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
… (so no OS read-ahead) single page reads which hurt performance ? I guess we really should try Mark Callaghan patches to… also can’t wait for Christoffer Hall’s work of Linux AIO support to be merged to the mainline. This also… so thread would rarely need to stall unable to perform any quick IO and unable to progress until scheduled read ahead can…
Comment: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
… — I have yet to do IO performance testing for 5.0. In theory, the changes for more IO threads in InnoDB are not… IO, but this is disabled because async IO didn’t work too well on Linux in the past. Now that Oracle runs on Linux and uses async IO, it…
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
… than a second as they can also be a performance killer for a busy application. Recently I have started… there is no good way to measure that. InnoDB_IO_r_bytes is the corresponding value in bytes. With… is available for MySQL Community 5.0.45 on Linux. May not work on other systems. Maciek …
Post: Fusion-io atomic writes and DirectFS
September 20, 2012 By Leave a Comment
… regular Linux filesystems: ext4 and xfs. Fusion-io will explain these features during our Percona Live New York conference and share performance numbers. It is not too late to register for conference and talk with Fusion-io engineers directly. “PerconaNY…
Comment: Is there room for more MySQL IO Optimization?
January 10, 2013 By 11 Comments
Hi Peter, what I meant about buffered I/O on Linux: – reads are fine (as data prefetch on FS is usually… MySQL server start taking over 40min for ex. just because Linux was slow to decide which page to remove from FS… — see http://dimitrik.free.fr/blog/archives/2012/11/mysql-performance-linux-io-and-fusionio-part-2.html for details).. And in most…
