Disconnected from the server, with ERROR 2013 reported

This topic describes how to handle ERROR 2013, where the connection to the server is disconnected in the MySQL-compatible mode of OceanBase Database.

Symptom

The session has been idle for a long period of time after the connection to the database is established. In this case, when you execute an SQL statement for viewing data in the ordr table, an error is reported, indicating that the connection is disconnected.

obclient [test]> SELECT * FROM ordr;
ERROR 2013 (HY000): Lost connection to MySQL server during query

Possible causes

In OceanBase Database, when the idle time of a session exceeds the specified threshold, the system closes the current connection and reports ERROR 2013 for the next operation.

Troubleshooting procedure

Take the following steps to view and modify the values of session-related variables. The following variable setting method takes effect only for the current session. To make the settings permanent, use the SET GLOBAL syntax to configure these variables, and then restart the session for the settings to take effect.

1. Reconnect to the corresponding MySQL tenant.

2. View time-related variables.

   obclient [test]> SHOW VARIABLES LIKE '%time%';
   +---------------------------------+------------------+
   | Variable_name                   | Value            |
   +---------------------------------+------------------+
   | connect_timeout                 | 10               |
   | default_password_lifetime       | 0                |
   | error_on_overlap_time           | OFF              |
   | explicit_defaults_for_timestamp | ON               |
   | interactive_timeout             | 10000            |
   | lock_wait_timeout               | 31536000         |
   | long_query_time                 | 10               |
   | max_execution_time              | 0                |
   | net_read_timeout                | 30               |
   | net_write_timeout               | 60               |
   | ob_pl_block_timeout             | 3216672000000000 |
   | ob_query_timeout                | 10000000         |
   | ob_trx_idle_timeout             | 86400000000      |
   | ob_trx_lock_timeout             | -1               |
   | ob_trx_timeout                  | 86400000000      |
   | system_time_zone                | +08:00           |
   | timestamp                       | 0                |
   | time_format                     | %H:%i:%s         |
   | time_zone                       | +8:00            |
   | wait_timeout                    | 10000            |
   +---------------------------------+------------------+
   20 rows in set
   

3. Set the value of the wait_timeout variable to 28800.

   obclient [test]> SET wait_timeout = 28800;
   Query OK, 0 rows affected
   

4. Set the value of the interactive_timeout variable to 28800.

   obclient [test]> SET interactive_timeout = 28800;
   Query OK, 0 rows affected
   

5. Query the ordr table again. You can query data properly.

   obclient [test]> SELECT * FROM ordr;
   +----+---------------------+---------------------+
   | id | gmt_create          | gmt_modified        |
   +----+---------------------+---------------------+
   |  1 | 2022-03-16 14:23:10 | 2022-03-16 14:23:10 |
   |  2 | 2022-03-16 14:23:10 | 2022-03-16 14:23:10 |
   |  3 | 2022-03-16 14:23:10 | 2022-03-16 14:23:10 |
   +----+---------------------+---------------------+
   3 rows in set
   

References

• For more information about the wait_timeout parameter, see wait_timeout.

• For more information about the interactive_timeout parameter, see interactive_timeout.