… was just hired by a web company and they experienced mysql crazy cpu loads since more than one year which lead every… load average, mysql master restart needed and apache servers as well. At first I did standard tuning and query tuning but it seemed… exactly what you describe: CPU context switches from 10k to 200k/300k so I observed the single mysql threads and I saw…
Post: Side load may massively impact your MySQL Performance
November 13, 2011 By 7 Comments
… mysqldump should have relatively little CPU needs and be bound by …mysql –mysql-host=localhost –mysql-table-engine=innodb –mysql-db=test –oltp-table-name=md_cache_test_small –oltp-table-size=1100000 –mysql-user=msandbox –mysql…buffer pool at all. For advanced tuning you might also look into …
Post: The Doom of Multiple Storage Engines
May 8, 2010 By 22 Comments
… it is not tuned to exploit full performance potential of any given storage engine. Synchronization The top level on MySQL side, such… transactions which require a lot of complications and performance overhead. MySQL has to do several fsync() calls per transaction commit to… could save a lot of CPU cycles by having storage format same as processing format. We could tune Optimizer to handle Innodb…
Post: Guidance for MySQL Optimizer Developers
September 20, 2009 By 4 Comments
… spend large portion of my life working on MySQL Performance Optimization and so MySQL Optimizer is quite important to me. For probably… keep database on SSD which has completely different ratio between CPU and IO cost. Focus on Execution Methods Performance problems can… to see tuning knobs (which relates to cost model and various optimizations) as well as simply hints. Any way MySQL could possibly…
Post: How fast can you sort data with MySQL ?
August 18, 2007 By 26 Comments
…as I used for MySQL Group by Performance Tests to see how much MySQL can sort 1.000…is quite smaller than even default value. The CPU in question was Pentium 4 having 1024K of …from these results: Benchmark your application Unfortunately general tuning guidelines can be wrong for your particular case,…
Post: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
…multiple cores becomes increasingly important as their number per CPU just keeps doubling. It is also rather …where already which may come in MySQL 5.2 or even MySQL 5.1. I surely would like…test properly before really enabling it. Innodb IO Tuning I should also mention Paul Tuckfield Keynote about…
Post: High Rate insertion with MySQL and Innodb
January 7, 2011 By 17 Comments
… 5.1 in this case) With MySQL 5.1 and Innodb Plugin we could see 40%+ CPU wasted on mutex spinlocks (per oprofile), which went down to about 15% in MySQL 5.5.8 with… room for more performance optimizations. Dmitri has good suggestions on tuning MySQL 5.5 and this is what I used for start…
Post: Why Swapping is bad for MySQL Performance ?
January 18, 2010 By 11 Comments
… up all Algorithms The database internals algorithms are tuned for things being in memory and if they…lets see what swapping does for concurrent (multi CPU, multi client) processing. Database Locks/Latches are …you may prefer to see slowdown instead of MySQL being killed because of out of memory but…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… 5.1: static MYSQL_SYSVAR_ULONG(thread_concurrency, srv_thread_concurrency, PLUGIN_VAR_RQCMDARG, “Helps in performance tuning in heavily concurrent environments…: Users have reported lots of InnoDB scalability problems from multicore CPU‘s. The most recent 5.0.xx behave better. We… your load is CPU bound and you’re scaling out you can get better performance by using couple of MySQL Servers on…
Post: Economics of Performance Optimization
March 13, 2008 By 9 Comments
… proper indexes or tuning couple of MySQL settings. When low hanging fruits are fixed you end up with either fine tuning which gives… have problems with latency rather than throughput. If single user CPU bound query takes 30 seconds you unlikely will be able… variety of companies on he market offering services around MySQL and LAMP and MySQL is one of them. Plus for large companies…
