Parameter Modifications

Last updated: 2021-11-30 15:54:20

    How do I modify the configuration parameters of a TencentDB for MySQL instance?

    In the TencentDB for MySQL console, click the instance ID in the instance list and enter the management page. Select Database Management > Parameter Settings. Common var\_name includes:

    VariableDescription
    character_set_serverDefault character set of the server
    connect_timeoutConnection timeout period
    long_query_timeA query that takes longer than this time is a slow query.
    max_allowed_packetMaximum packet length
    max_connectionsMaximum number of connections
    sql_modeCurrent SQL mode of the server
    table_open_cacheNumber of tables opened by all threads. Increasing this value will increase the number of file descriptors that mysqld is requested to open.
    wait_timeoutNon-interactive connection timeout period

    You can view more configuration parameters in Database Management > Parameter Settings in the console.

    How do I set Chinese queries in TencentDB for MySQL?

    Chinese characters are currently not supported in TencentDB for MySQL.

    How do I enable the scheduler feature in TencentDB for MySQL?

    In the TencentDB for MySQL console, click the instance ID in the instance list and enter the management page. Select Database Management > Parameter Settings and set the event_scheduler parameter to ON.

    How do I increase the connection timeout period in TencentDB for MySQL?

    In the TencentDB for MySQL console, click the instance ID in the instance list and enter the management page. Select Database Management > Parameter Settings and modify the wait_timeout parameter.

    How do I modify the group_concat_max_len parameter in TencentDB for MySQL?

    In the TencentDB for MySQL console, click the instance ID in the instance list and enter the management page. Select Database Management > Parameter Settings and modify the group_concat_max_len parameter.

    How do I locate the SQL statements for full-table scan in TencentDB for MySQL?

    Full-table scan statements are not recorded by default. To locate them, set the log_queries_not_using_indexes parameter to ON in Parameter Settings in the TencentDB for MySQL console. We recommend that you only enable this parameter for a short period of time.

    How do I change the default character set in TencentDB?

    TencentDB for MySQL supports LATIN1, GBK, UTF8 (default), and UTF8MB4 character sets.

    Although TencentDB supports changing the default character set, we recommend that you explicitly specify the table encoding when creating a table and specify the connection encoding when establishing a connection for more portable application experience. For more information on MySQL default character set and how to modify it, see Use Limits. You can also modify the character set in the TencentDB for MySQL console.

    What should I do if the lower_case_table_names parameter failed to be modified?

    You can modify the lower_case_table_names parameter in the TencentDB for MySQL console. If it is set to 1, the case-insensitive mode is enabled. Pay attention to the following when modifying the parameter:

    • Modifying the parameter will restart the instance.
    • Make sure that all database names and table names in the instance are using lowercase letters before modifying the parameter; otherwise, an error will be reported if there is any database name or table name using uppercase letters.
    • The parameter cannot be modified in MySQL v8.0 which supports the case-sensitive mode by default.

    Check uppercase table names:

    select table_schema,table_name from information_schema.tables where   table_schema not in("mysql","information_schema") and (md5(table_name)<>md5(lower(table_name)) or md5(table_schema)<>md5(lower(table_schema)));
    

    Check uppercase database names:

    select SCHEMA_NAME from information_schema.SCHEMATA where md5(SCHEMA_NAME)<>md5(lower(SCHEMA_NAME));