Manual:Objectcache table

Objectcache table is used for a few generic cache operations if not using Memcached. Its content can be deleted and excluded from backups as it will be regenerated when needed.

keyname
Unique identifier of the cached object. e.g. :user:id:

value
Cached object.

exptime
Date the cache entry should be expired, and therefore removed.

Versions
+-++--+-+-+---+ +-++--+-+-+---+ +-++--+-+-+---+
 * Field  | Type           | Null | Key | Default | Extra |
 * keyname | varbinary(255) | NO  | PRI |         |       |
 * value  | mediumblob     | YES  |     | NULL    |       |
 * exptime | datetime      | YES  | MUL | NULL    |       |

describe objectcache; +-++--+-+-+---+ +-++--+-+-+---+ +-++--+-+-+---+
 * Field  | Type           | Null | Key | Default | Extra |
 * keyname | varbinary(255) |     | PRI |         |       |
 * value  | mediumblob     | YES  |     | NULL    |       |
 * exptime | datetime      | YES  | MUL | NULL    |       |

DESCRIBE objectcache; in MediaWiki 1.8 gives the following: +-++--+-+-+---+ +-++--+-+-+---+ +-++--+-+-+---+
 * Field  | Type       | Null | Key | Default | Extra |
 * keyname | char(255) | NO   | PRI | NULL    |       |
 * value  | mediumblob | YES  |     | NULL    |       |
 * exptime | datetime  | YES  | MUL | NULL    |       |

+-++--+-+-+---+ +-++--+-+-+---+ +-++--+-+-+---+
 * Field  | Type       | Null | Key | Default | Extra |
 * keyname | char(255) | NO   | PRI | NULL    |       |
 * value  | mediumblob | YES  |     | NULL    |       |
 * exptime | datetime  | YES  | MUL | NULL    |       |

+-+-+--+-+-+---+ +-+-+--+-+-+---+ +-+-+--+-+-+---+
 * Field  | Type            | Null | Key | Default | Extra |
 * keyname | varbinary(255) | NO   | PRI | NULL    |       |
 * value  | mediumblob      | YES  |     | NULL    |       |
 * exptime | datetime       | YES  | MUL | NULL    |       |

+-++--+-+-+---+ +-++--+-+-+---+ +-++--+-+-+---+
 * Field  | Type       | Null | Key | Default | Extra |
 * keyname | char(255) | NO   | PRI | NULL    |       |
 * value  | mediumblob | YES  |     | NULL    |       |
 * exptime | datetime  | YES  | MUL | NULL    |       |