• Relational Database Service

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  2. Relational Database Service
  3. User Guide
  4. Working with RDS for MySQL
  5. Modifying Parameters in a Parameter Group

Modifying Parameters in a Parameter Group

You can modify parameters in custom parameter groups.

NOTE:

RDS has default parameter groups whose parameter values cannot be changed. You can view them by clicking their names. If a custom parameter group is set incorrectly and causes a database reboot to fail, you can use a default parameter group to reset the database.

Procedure

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click Service List. Under Database, click Relational Database Service to go to the RDS console.
  4. On the Parameter Group Management page, click Custom Groups and then click the target parameter group.
  5. Modify the parameter values as required.

    Relevant parameters are as follows:

    • For details on parameter descriptions, visit the MySQL official website.
    • The values of innodb_spin_wait_delay, query_alloc_block_size, innodb_buffer_pool_size, innodb_log_file_size, and thread_stack are determined by the DB instance specifications. If you increase their values, database performance may be affected.
    • If key_buffer_size is set to a value smaller than 4096, the parameter modification will fail.

      If max_seeks_for_key is set to a small value, database operations such as selecting or showing global variables will be affected.

      If max_connections is set to a small value, database access will be affected.

      If max_join_size is set to a small value, the database will become unavailable.

      If sql_select_limit is set to a small value, database queries may become unavailable.

    • The values of parameters prefixed with performance_schema vary according to the performance_schema value (ON or OFF) and are determined by the MySQL engine. These parameters are left blank before being specified.

      Default values of the following parameters vary according to DB instance specifications: innodb_buffer_pool_size, innodb_log_buffer_size, innodb_log_files_in_group, slave_parallel_workers, max_connections, and back_log. Their values are default before being specified.

    Available operations are as follows:

    After you modify parameters in a parameter group, some modifications immediately take effect for the DB instances to which the parameter group applies. Exercise caution when performing this operation.

    • To save the modifications, click Save.
    • To cancel the modifications, click Cancel.
    • To preview the modifications, click Preview.
    NOTE:

    For details on the description of parameter group statuses, see section Parameter Group Statuses.

    After you modify parameters in a parameter group, you need to click the DB instance to view the status of the parameter group. On the displayed Basic Information page, if the status of the parameter group is Pending reboot, you must reboot the DB instance for the modifications to take effect.

    Rebooting is always required after modifying parameters in a parameter group under the following circumstances:

    • The modified parameter group applies to primary/standby DB instances. In this case, the standby DB instance will also be changed accordingly after the reboot.
    • The modified parameter group applies to a read replica.

NOTE:

You can also modify parameters in a parameter group by clicking the DB instance to which the parameter group applies on the Instance Management page. In the Instance Information area on the displayed Basic Information page, click the parameter group name in the Parameter Group field. On the displayed page, modify relevant parameters as required.