Optimizar MYSQL.

Si tienes la necesidad de optimizar mysql puedes usar el siguiente programa:

MySQLTunner

http://blog.mysqltuner.com/download/

Lo descargas con

wget mysqltuner.pl

y lo ejecutas

perl mysqltuner.pl

Te preguntara el usuario de la base de datos, y el password de la base de datos.

y te dara instrucciones de que variables configurar en el archivo my.cnf asi como consejos para tus aplicaciones que usen mysql.

Ejemplo

Server:~# perl mysqltuner.pl
>> MySQLTuner 1.0.1 – Major Hayden
>> Bug reports, feature requests, and downloads at http://mysqltuner.com/
>> Run with ‘–help’ for additional options and output filtering
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password:

——– General Statistics ————————————————–
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.0.51a-24+lenny3-log
[OK] Operating on 64-bit architecture

——– Storage Engine Statistics ——————————————-
[--] Status: +Archive -BDB -Federated -InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 175M (Tables: 419)
[OK] Total fragmented tables: 0

——– Performance Metrics ————————————————-
[--] Up for: 20m 47s (6K q [5.370 qps], 1K conn, TX: 21M, RX: 525K)
[--] Reads / Writes: 96% / 4%
[--] Total buffers: 138.0M global + 2.6M per thread (300 max threads)
[OK] Maximum possible memory usage: 925.5M (45% of installed RAM)
[OK] Slow queries: 0% (0/6K)
[OK] Highest usage of available connections: 1% (4/300)
[OK] Key buffer size / total MyISAM indexes: 32.0M/31.8M
[!!] Key buffer hit rate: 89.2% (14K cached / 1K reads)
[OK] Query cache efficiency: 22.9% (839 cached / 3K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 273 sorts)
[!!] Joins performed without indexes: 13
[OK] Temporary tables created on disk: 24% (96 on disk / 394 total)
[OK] Thread cache hit rate: 99% (4 created / 1K connections)
[!!] Table cache hit rate: 5% (47 open / 925 opened)
[OK] Open file limit used: 2% (95/4K)
[OK] Table locks acquired immediately: 100% (2K immediate / 2K locks)

——– Recommendations —————————————————–
General recommendations:
MySQL started within last 24 hours – recommendations may be inaccurate
Adjust your join queries to always utilize indexes
Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
join_buffer_size (> 128.0K, or always use indexes with joins)
table_cache (> 2048)