Manual:User autocreate serial table

The user_autocreate_serial tables is for sequential name generation for auto-created temporary users.

uas_shard
The segment of ID space, ID mod N, referred to by this row.

uas_value
The maximum allocated ID value.

Schema summary
+---+--+--+-+-+---+ +---+--+--+-+-+---+ +---+--+--+-+-+---+
 * Field    | Type             | YES | Key | Default | Extra |
 * uas_shard | int(10) unsigned | YES  | PRI | NULL    |       |
 * uas_value | int(10) unsigned | YES  |     | NULL    |       |

Indexes
 +++--+--+-+---+-+--++--++-+---+ +++--+--+-+---+-+--++--++-+---+ +++--+--+-+---+-+--++--++-+---+
 * Table                 | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
 * user_serial |         0 | PRIMARY  |            1 | uas_shard   | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |