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Version: 0.17

MySQL

Connect​

You can connect to GreptimeDB using MySQL via port 4002.

mysql -h <host> -P 4002 -u <username> -p
  • For how to setup username and password for GreptimeDB, please refer to Authentication.
  • If you want to use other ports for MySQL, please refer to Protocol options in the configuration document.

Table management​

Please refer to Table Management.

Ingest data​

Please refer to SQL.

Query data​

Please refer to SQL.

Time zone​

GreptimeDB's MySQL protocol interface follows original MySQL on how to deal with time zone.

By default, MySQL uses its server time zone for timestamp. To override, you can set time_zone variable for current session using SQL statement SET time_zone = '<value>';. The value of time_zone can be any of:

  • The server's time zone: SYSTEM.
  • Offset to UTC such as +08:00.
  • Any named time zone like Europe/Berlin.

Some MySQL clients, such as Grafana MySQL data source, allow you to set the time zone for the current session. You can also use the above values when setting the time zone.

You can use SELECT to check the current time zone settings. For example:

SELECT @@system_time_zone, @@time_zone;

The result shows that both the system time zone and the session time zone are set to UTC:

+--------------------+-------------+
| @@system_time_zone | @@time_zone |
+--------------------+-------------+
| UTC                | UTC         |
+--------------------+-------------+

Change the session time zone to +1:00:

SET time_zone = '+1:00'

Then you can see the difference between the system time zone and the session time zone:

SELECT @@system_time_zone, @@time_zone;

+--------------------+-------------+
| @@system_time_zone | @@time_zone |
+--------------------+-------------+
| UTC                | +01:00      |
+--------------------+-------------+

For information on how the time zone affects data inserts and queries, please refer to the SQL documents in the Ingest Data and Query Data sections.

Query Timeout​

You can set the max_execution_time variable for the current session using SQL statement SET max_execution_time = <value> or SET MAX_EXECUTION_TIME = <value>, which specifies the maximum time in milliseconds for a read-only statement to execute. The server will terminate the query if it exceeds the specified time.

For example, to set the maximum query execution time to 10 seconds:

SET max_execution_time=10000;