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 OceanBase Database in MySQL mode.

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 the ERROR 2013 error 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%';
   +---------------------------------+------------------+
   | Parameter                       | 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.

   Note

   wait_timeout specifies the time in seconds that the server waits for an interactive connection to become active before closing it.

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

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

   Note

   interactive_timeout specifies the time in seconds that the server waits for an non-interactive connection to become active before closing it.

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

5. View the ordr table again. The table can be queried normally.

   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