Help Center/ Relational Database Service/ User Guide (Paris Region) / Working with RDS for PostgreSQL/ Parameter Template Management/ Modifying Parameters
Updated on 2023-06-19 GMT+08:00
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Modifying Parameters

You can modify parameters in a custom parameter template to optimize RDS database performance.

You can change parameter values in custom parameter templates only and cannot change parameter values in default parameter templates.

If you modify a parameter, when the modification takes effect is determined by the type of parameter.

The RDS console displays the statuses of DB instances to which the parameter template applies. For example, if the DB instance has not used the latest modifications made to its parameter template, its status is Pending reboot. You need to manually reboot the DB instance for the latest modifications to take effect for that DB instance.

RDS has default parameter templates whose parameter values cannot be changed. You can view these parameter values by clicking the default parameter templates. If a custom parameter template is set incorrectly, the database startup may fail. You can re-configure the custom parameter template according to the configurations of the default parameter template.

Modifying Parameter Template Parameters

  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. The RDS console is displayed.
  4. Choose Parameter Template Management in the navigation pane on the left. On the Custom Templates page, click the target parameter template.
  5. Modify parameters as required.

    Relevant parameters are as follows:

    • For details on parameter descriptions, visit the PostgreSQL official website.
    • If log_statement is set to ddl, mod, or all, the operations for creating and deleting database users (including passwords and other sensitive information) are recorded. This operation affects database performance. Exercise caution when setting this parameter.
    • The search_path parameter must be set to a schema sequence where schemas are separated by commas (,). Ensure that the schemas exist. Otherwise, the database performance will be affected.
    • Enabling the following parameters will affect the database performance: log_hostname, log_duration, log_connections, and log_disconnections. Exercise caution when enabling these parameters.
    • If you enable the parameter log_duration, SQL statements containing sensitive information may be recorded in logs. You are advised to disable this parameter.
    • If the parameter log_min_duration_statement is set to 0, SQL statements containing sensitive information will be recorded in logs. You are advised to disable this parameter by setting it to -1.
    • The parameters nls_timestamp_format and nls_date_format control the input and output formats of timestamp and date. They support PostgreSQL Enhanced Edition only.
      • The nls_timestamp_format parameter defines the timestamp format. The nls_date_format defines the date format. Their functions are the same and you can change either of them.
    • The temp_file_limit parameter specifies the maximum amount of disk space (in KB) that a session can use for temporary files. It supports PostgreSQL 11 and 12 only. Changing this parameter value is a high-risk operation. Exercise caution when deciding to perform this operation.
      • If the parameter value exceeds the threshold, the DB instance will become unavailable.
      • If the parameter value is changed to a larger value for temporary use but is not changed to the original value after the use, the disk space will be continuously used to store temporary files. If the disk space is used up, services will be interrupted and the DB instance will become unavailable.

    Available operations are as follows:

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

Modifying Instance Parameters

  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. The RDS console is displayed.
  4. On the Instance Management page, click the target DB instance.
  5. In the navigation pane on the left, choose Parameters. On the displayed page, modify parameters as required.

    Relevant parameters are as follows:
    • For details on parameter descriptions, visit the PostgreSQL official website.
    • If log_statement is set to ddl, mod, or all, the operations for creating and deleting database users (including passwords and other sensitive information) are recorded. This operation affects database performance. Exercise caution when setting this parameter.
    • The search_path parameter must be set to a schema sequence where schemas are separated by commas (,). Ensure that the schemas exist. Otherwise, the database performance will be affected.
    • Enabling the following parameters will affect the database performance: log_hostname, log_duration, log_connections, and log_disconnections. Exercise caution when enabling these parameters.
    • If you enable the parameter log_duration, SQL statements containing sensitive information may be recorded in logs. You are advised to disable this parameter.
    • If the parameter log_min_duration_statement is set to 0, SQL statements containing sensitive information will be recorded in logs. You are advised to disable this parameter by setting it to -1.
    • The parameters nls_timestamp_format and nls_date_format control the input and output formats of timestamp and date. They support PostgreSQL Enhanced Edition only.
      • The nls_timestamp_format parameter defines the timestamp format. The nls_date_format defines the date format. Their functions are the same and you can change either of them.
    • The temp_file_limit parameter specifies the maximum amount of disk space (in KB) that a session can use for temporary files. It supports PostgreSQL 11 and 12 only. Changing this parameter value is a high-risk operation. Exercise caution when deciding to perform this operation.
      • If the parameter value exceeds the threshold, the DB instance will become unavailable.
      • If the parameter value is changed to a larger value for temporary use but is not changed to the original value after the use, the disk space will be continuously used to store temporary files. If the disk space is used up, services will be interrupted and the DB instance will become unavailable.

    Available operations are as follows:

    After you modify instance parameters, the modifications immediately take effect for the DB instance.

    After you modify parameters in a parameter template, you need to view the status of the DB instance to which the parameter template applies. If the status is Pending reboot, you must reboot the DB instance for the modifications to take effect.
    • If you have modified parameters of a primary DB instance, you need to reboot the primary DB instance for the modifications to take effect. (For primary/standby DB instances, the parameter modifications also apply to the standby DB instance.)
    • If you have modified parameters of a read replica, you need to reboot the read replica for the modifications to take effect.
    • To save the modifications, click Save.
    • To cancel the modifications, click Cancel.
    • To preview the modifications, click Preview.

    After parameters are modified, you can view parameter change history by referring to section Viewing Parameter Change History.