Extension:CheckUser/cu useragent table

A table for the CheckUser extension used to store unique values of the user agent string. The rows in this table are referenced by the cuc_agent_id , cule_agent_id , cupe_agent_id columns. While this table will in most cases only have one row for a given user agent string, this is not guaranteed in case of race conditions when inserting a user agent string not seen before.

In MediaWiki release 1.42, this table is unused. However, in future releases this table will be used.

Primary key, used to uniquely identify a cu_changes row. Referenced by the cuc_agent_id , cule_agent_id , cupe_agent_id columns.

The value of the user agent header. The value of this header may be held by other rows in this table if a race condition occurred when inserting this row, but usually the values in this column should be unique.

DESCRIBEcu_useragent;

+-----------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------------------+------+-----+---------+----------------+
| cuua_id | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| cuua_text | varbinary(255) | NO | MUL | NULL | |
+-----------+---------------------+------+-----+---------+----------------+

SHOWINDEXINcu_useragent;

+--------------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+--------------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| cu_useragent | 0 | PRIMARY | 1 | cuua_id | A | 0 | NULL | NULL | | BTREE | | |
| cu_useragent | 1 | cuua_text | 1 | cuua_text | A | 0 | NULL | NULL | | BTREE | | |
+--------------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

• Wikimedia extension database tables