Manual:Objectcache table

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MediaWiki database layout

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.

Fields

keyname

Unique identifier of the cached object. e.g. <instance>:user:id:<userid>

value

Cached object.

exptime

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

Versions

MediaWiki versions:

1.19 – 1.20

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

MediaWiki version:

1.18

describe objectcache;

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

MediaWiki version:

1.8

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    |       |
+---------+------------+------+-----+---------+-------+

MediaWiki version:

1.9

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

MediaWiki version:

1.11

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

MediaWiki version:

1.12

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