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TencentDB for MySQL
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    Parameter Modifications

    Last updated: 2024-11-27 10:52:26
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      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:
      Variable
      Description
      character_set_server
      Default character set of the server
      connect_timeout
      Connection timeout period
      long_query_time
      A query that takes longer than this time is a slow query.
      max_allowed_packet
      Maximum packet length
      max_connections
      Maximum number of connections
      sql_mode
      Current SQL mode of the server
      table_open_cache
      Number of tables opened by all threads. Increasing this value will increase the number of file descriptors that mysqld is requested to open.
      wait_timeout
      Non-interactive connection timeout period
      You can view more configuration parameters in Database Management > Parameter Settings in the console.

      Does TencentDB for MySQL Support Queries by Using Chinese Commands?

      Currently, TencentDB for MySQL does not support queries by using Chinese commands. For instance, querying the information of an instance with the ID cdb-nieng1e.

      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 MySQL Console.

      How do I view the character set collation in TencentDB?

      TencentDB for MySQL allows you to set the character set collation when creating an instance. You can select a character set to provide a case-sensitive, accent-sensitive, or binary collation for your data, but doing so will affect the results of relevant database operations. You can run the show collation command to view the collation. Sample:
      show collation where charset ='utf8mb4';
      Collation description
      Collation Option
      Description
      _CS
      Case-sensitive.
      _CI
      Case-insensitive.
      _AS
      Accent-sensitive. This option indicates that the sorting will be accent-sensitive; for example, "a" and "ấ" are different characters.
      _AI
      Accent-insensitive.
      _BIN
      Binary.
      Character set suffix description
      Instance Character Set Suffix
      Description
      _CI_AI
      Case-insensitive and accent-insensitive
      _CI_AS
      Case-insensitive and accent-sensitive
      _CS_AI
      Case-sensitive and accent-insensitive
      _CS_AS
      Case-sensitive and accent-sensitive

      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.
      Before modifying the parameter, make sure that all database and table names in the instance are lowercase; otherwise, an error will be reported if any of them is uppercase.
      The parameter cannot be modified in MySQL 8.0 as it 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));
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