Problème d'optimisation de MySQL

Bonjour,

J'aurai besoin de votre aide pour optimiser mon serveur MySQL car mon CPU est actuellement à 100% et j'ai un Load Average de malade :

Pièce jointe 152339

J'utilise donc Mysql Tuner pour l'optimisé mais j'ai un peu de mal à faire descendre la charge de mon CPU.

Voici ci-dessous ce que me retourne MysqlTuner (Par contre là ça fait moins de 24 heures que j'ai redémarrer Mysql):

Citation:

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-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.5.35-0+wheezy1-log
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics -------------------------------------------
[--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 2G (Tables: 653)
[--] Data in InnoDB tables: 289M (Tables: 462)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[!!] Total fragmented tables: 496

-------- Security Recommendations -------------------------------------------
[OK] All database users have passwords assigned

-------- Performance Metrics -------------------------------------------------
[--] Up for: 16s (19K q [1K qps], 683 conn, TX: 38M, RX: 2M)
[--] Reads / Writes: 93% / 7%
[--] Total buffers: 736.0M global + 4.6M per thread (600 max threads)
[OK] Maximum possible memory usage: 3.4G (5% of installed RAM)
[OK] Slow queries: 0% (4/19K)
[OK] Highest usage of available connections: 2% (13/600)
[OK] Key buffer size / total MyISAM indexes: 16.0M/398.5M
[OK] Key buffer hit rate: 99.3% (948K cached / 6K reads)
[OK] Query cache efficiency: 74.1% (13K cached / 17K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 1K sorts)
[!!] Joins performed without indexes: 105
[!!] Temporary tables created on disk: 42% (934 on disk / 2K total)
[OK] Thread cache hit rate: 97% (14 created / 683 connections)
[OK] Table cache hit rate: 25% (1K open / 4K opened)
[OK] Open file limit used: 0% (1K/1M)
[OK] Table locks acquired immediately: 100% (8K immediate / 8K locks)
[OK] InnoDB data size / buffer pool: 289.1M/320.0M

-------- Recommendations -----------------------------------------------------
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
MySQL started within last 24 hours - recommendations may be inaccurate
Adjust your join queries to always utilize indexes
Temporary table size is already large - reduce result set size
Reduce your SELECT DISTINCT queries without LIMIT clauses
Variables to adjust:
join_buffer_size (> 2.0M, or always use indexes with joins)

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Et voici mon fichier My.cnf :

Citation:

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#

[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock

[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0

[mysqld]

user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking

# Paramètres modifiés par les recommandations sqltuner
tmp_table_size = 256M
max_heap_table_size = 256M
wait_timeout = 24000
interactive_timeout = 24000
innodb_buffer_pool_size = 320M
join_buffer_size = 2M
# Fin des modifications d'optimisation

key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
max_connections = 600
table_cache = 512000
#thread_concurrency = 10

query_cache_limit = 1M
query_cache_size = 128M

log_slow_queries = /var/log/mysql/mysql-slow.log
long_query_time = 1
#log-queries-not-using-indexes

#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name

# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem

[mysqldump]
quick
quote-names
max_allowed_packet = 16M

[mysql]
#no-auto-rehash # faster start of mysql but no tab completition

[isamchk]
key_buffer = 16M

!includedir /etc/mysql/conf.d/

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Donc si vous avez des idées, des conseils pour m'aider a résoudre ce soucis je vous en remercie.