… one more point to consider. Starting the MySQL 5.1 + InnoDB-plugin and later MySQL 5.5 (or equally Percona Server 5.1 and 5.5), InnoDB uses “asynchronous” IO in Linux. Let’s…. I would still use value 2 or 4, to avoid scheduling overhead from single thread, but it does not seem critical…
Post: Linux schedulers in tpcc like benchmark
January 30, 2009 By 19 Comments
… earlier that IO scheduler CFQ coming by default in RedHat / CentOS 5.x may be not so good for MySQL. And yesterday…
Post: MySQL Limitations Part 4: One thread per connection
October 27, 2010 By 14 Comments
…the way MySQL handles connections, allocating one thread per connection to the server. MySQL is a… has had excellent threading support practically forever; Linux has very good threading now, but that… server. That increases the overhead from thread scheduling, and potentially memory usage as well. I…
Post: Linux IO Schedulers and MySQL
January 30, 2007 By 7 Comments
… about Linux IO Schedulers today which is quite interesting. It goes in details about schedulers and explains in which of workloads which of schedulers… over years. Long time ago “AS” scheduler could be several times slower than deadline for MySQL workloads such as SysBench or DBT2… the docs it is mentioned it uses “per process” scheduling while MySQL is single process but single thread – does each thread gets…
Post: What should we say about Sun buying MySQL ?
January 21, 2008 By 2 Comments
… blogging about MySQL who has not commented about announced Sun – MySQL Deal. In fact I was just on extremely busy travel schedule last… work as good as they can with Linux ? Will Sun follow Open Source spirit of MySQL Founders (and I mean Founders because… this is mostly positive development. Sun will work on expanding MySQL market further which will mean more consulting work available, and…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 11 Comments
…# Aspersa System Summary Report ############################## Platform | Linux Release | Ubuntu 10.04.2 LTS … {OUT OF SPEC} Other … # Disk Schedulers And Queue Size ############################# sda | [deadline] 128 # …not different MySQL configurations, I didn’t try out different MySQL versions …
Post: The new cool MySQL patch has landed! Check your queries performance!
October 31, 2007 By 16 Comments
…: 56 Rows_examined: 1113 LOGGING OF THE REPLICATED STATEMENTS Normally MySQL will not write into slow log any queries executed by… is the counter for the number of page read operations scheduled. The acutal number of read operations may be different, but… any important system! The patch is available for MySQL Community 5.0.45 on Linux. May not work on other systems. Maciek…
Post: How Innodb Contention may manifest itself
July 28, 2011 By 1 Comment
… though multiple fixes have been implemented in Percona Server and MySQL 5.5, there are still workloads in which case mutex… time while you’re upgrading to Percona Server or newer MySQL version or doing application/architecture changes. Reducing number of competing… to consider a high number. With modern hardware and modern Linux process scheduler you can be looking at 500.000+ context switches…
Post: Setting up XFS on Hardware RAID -- the simple edition
December 16, 2011 By 9 Comments
… boundary. /dev/sda2 * 7813120 27344895 9765888 83 Linux /dev/sda3 27344896 856422399 414538752 83 Linux Several months ago my colleague Aurimas posted… use some simple ones: /var/lib/mysql xfs nobarrier,noatime,nodiratime Setting the IO scheduler This is a commonly missed step related…
Post: Living with backups
November 6, 2008 By 28 Comments
… may be preferred by the I/O scheduler over random I/O coming from MySQL, but also such large I/O requests…. This is unfortunately not something you can do with standard Linux tools like cp, scp or tar. However for example rsync… one-liners) On Linux there is also a utility called ionice. It allows to affect how I/O scheduler will be dealing…
