MySQLTuner-perl/INTERNALS.md

MySQLTuner Internals

MySQLTuner steps

• Header Print
• Get login information
• Set up some OS variables
• Toss variables/status into hashes
• Get information about the tuning connexion
• Check current MySQL version
• Suggest 64-bit upgrade
• Show enabled storage engines
• Show informations about databases (option: --dbstat)
• Show informations about indexes (option: --idxstat)
• Display some security recommendations
• Calculate everything we need
• Print the server stats
• Print MyISAM stats
• Print InnoDB stats
• Print AriaDB stats
• Print replication info
• Make recommendations based on stats
• Close reportfile if needed
• Dump result if debug is on

MySQLTuner get login information steps

• Is a login possible?
  • Force socket?
  • Remote connection?
    • Specifying available RAM is required
  • Got user/pass on command line?
  • mysql-quickbackup credentials available?
  • Plesk credentials available?
  • DirectAdmin credentials available?
  • Debian maintenance account credentials available?
  • Just try a login
    • If working, and .my.cnf isn't there, WARNING
    • If working, and .my.cnf is there, okay
  • Prompt for creds on the console

MySQLTuner system checks

• 32-bit w/>2GB RAM check

MySQLTuner Server version checks

• EOL MySQL version check
• Currently MySQL < 5.1 are EOF considerated.

MySQL Storage engine general information

• Get storage engine counts/stats
  • Check for DB engines that are enabled but unused
  • Look for fragmented tables
  • Look for auto-increments near capacity

MySQLTuner security checks

• Is anonymous user present?
• Users without passwords
• Users w/username as password
• Users w/o host restriction
• Weak password check (possibly using cracklib later?)
• Using basic_passwords.txt as password database
• Password list checks can be avoid (option: --skippassword)

MySQLTuner database information

• Rows number
• Total size
• Data size
• Percentage of data size
• Index size
• Percentage of index size

MySQLTuner index information

• Top 10 worth selectivity index
• Index Cardinality
• Index Selectivity
• Misc information about index definition
• Misc information about index size

MySQLTuner Connections information

• Percentage of used connections (<85%)
• Percentage of aborted connections (<3%)

MySQLTuner server information

• Uptime: If MySQL started within last 24 hours
• Bytes received and sent
• Number of connections
• Percentage between reads and writes
• Is binary log activated ?
  • Is GTID mode activated ?

MySQLTuner global buffer information

• Key Buffer
• Max Tmp Table
• Is Query cache activated ?
  • Query Cache Buffers
  • Query Cache DISABLED, ALL REQUEST or ON DEMAND
  • Query Cache Size
• Per Thread Buffer
  • Read Buffer
  • Read RND Buffer
  • Sort Buffer
  • Thread stack
  • Join Buffer
  • Binlog Cache Buffers size if activated

MySQLTuner memory checks

• Get total RAM/swap
• Is there enought memory for max connections reached by MySQL ?
• Is there enought memory for max connections allowed by MySQL ?
• Max percentage of memory used(<85%)

MySQLTuner slow queries checks

• Percentage of Slow queries (<5%)

MySQLTuner InnoDB information

• InnoDB Buffer Pool Size
  • If possible, innodb_buffer_pool_size should be greater data and index size for Innodb Table
  • Innodb_buffer_pool_size should around 75 to 80 % of the available system memory.
• InnoDB Buffer Pool Instances
  • MySQL needs 1 instanes per 1Go of Buffer Pool
  • innodb_buffer_pool instances = round(innodb_buffer_pool_size / 1Go)
  • innodb_buffer_pool instances must be equals or lower than 64
• InnoDB Buffer Pool uUsage
  • If more than 20% of InnoDB buffer pool is not used, MySQLTuner raise an alert.
• InnoDB Read effiency
  • Ratio of read without locks
• InnoDB Write effiency
  • Ratio of write without locks
• InnoDB Log Waits
  • Checks that no lock is used on Innodb Log.

MySQLTuner ARIADB information

• TODO

MySQLTuner MYISAM information