====== Percona XtraDB ======

  * [[Percona]]

  * [[https://en.wikipedia.org/wiki/Comparison_of_MySQL_database_engines|Comparison of MySQL database engines]]
  * [[http://www.mysqlperformanceblog.com/2006/07/17/show-innodb-status-walk-through/|SHOW INNODB STATUS walkthrough]]

Percona XtraDB is an enhanced version of InnoDB database engine.

InnoDB features:

  * Default storage engine in MySQL 5.5
  * InnoDB recovers from a crash or other unexpected shutdown by replaying its logs
  * InnoDB automatically groups together multiple concurrent inserts and flushes them to disk at the same time
  * ACID compliant
  * Transactional support: data integrity is guaranteed in the entire query process
  * InnoDB uses row-level locking, as opposed to table locking in MyISAM.  InnoDB can modify multiple rows concurrently, where MyISAM can only do one at a time
  * Full text search (same as MyISAM)
  * Foreign key constraints
  * Designed for high performance
  * Hot backup: do a full backup while reads/writes are still happening
  * Updates are written to the log first, and then the changes are made to the database

XtraDB features:

  * Backwards compatible with InnoDB
  * Faster performance
  * Better scalability
  * Better tunability
  * More statistics
  * Improvements in handing multiple concurrent queries
  * NoSQL support (experimental): You can access your data with both NoSQL and SQL statements
  * Increased shutdown times
  * Corrupted tables are disabled, instead of bringing down the database server
  * Can export single tables (n/a in InnoDB)
  * Buffer is saved during restarts
  * Slow query logs in microseconds instead of in seconds
  * Improved SHOW INNODB STATUS
  * Improved SHOW PROCESSLIST