Amazon RDS for Db2 parameters - Amazon Relational Database Service

Amazon RDS for Db2 parameters

Amazon RDS for Db2 uses three types of parameters: database manager configuration parameters, registry variables, and database configuration parameters. You can manage the first two types through parameter groups and the last type through the rdsadmin.update_db_param stored procedure.

By default, an RDS for Db2 DB instance uses a DB parameter group that is specific to a Db2 database and DB instance. This parameter group contains parameters for the IBM Db2 database engine, specifically the database manager configuration parameters and registry variables. For information about working with parameter groups, see Working with parameter groups.

RDS for Db2 database configuration parameters are set to the default values of the storage engine that you have selected. For more information about Db2 parameters, see the Db2 database configuration parameters in the IBM Db2 documentation.

Viewing the parameters in parameter groups

The database manager configuration parameters and the registry variables are set in parameter groups. You can view the database manager configuration parameters and the registry variables for a specific Db2 version by using the AWS Management Console, the AWS CLI, or the RDS API.

To view the parameter values for a DB parameter group
  1. Sign in to the AWS Management Console and open the Amazon RDS console at https://console.aws.amazon.com/rds/.

  2. In the navigation pane, choose Parameter groups.

    The DB parameter groups appear in a list.

  3. Choose the name of the parameter group to see its list of parameters.

You can view the database manager configuration parameters and the registry variables for a Db2 version by running the describe-engine-default-parameters AWS CLI command. Specify one of the following values for the --db-parameter-group-family option:

  • db2-ae-11.5

  • db2-se-11.5

For example, to view the parameters for Db2 Standard Edition 11.5, run the following command:

aws rds describe-engine-default-parameters --db-parameter-group-family db2-se-11.5

This command produces output similar to the following example:

{ "EngineDefaults": { "Parameters": [ { "ParameterName": "agent_stack_sz", "ParameterValue": "1024", "Description": "You can use this parameter to determine the amount of memory that is allocated by Db2 for each agent thread stack.", "Source": "engine-default", "ApplyType": "static", "DataType": "integer", "AllowedValues": "256-32768", "IsModifiable": false }, { "ParameterName": "agentpri", "ParameterValue": "-1", "Description": "This parameter controls the priority given to all agents and to other database manager instance processes and threads by the operating system scheduler. This priority determines how CPU time is allocated to the database manager processes, agents, and threads relative to other processes and threads running on the machine.", "Source": "engine-default", "ApplyType": "static", "DataType": "integer", "AllowedValues": "1-99", "IsModifiable": false }, ... ] } }

To list only the modifiable parameters for Db2 Standard Edition 11.5, run the following command:

For Linux, macOS, or Unix:

aws rds describe-engine-default-parameters \ --db-parameter-group-family db2-se-11.5 \ --query 'EngineDefaults.Parameters[?IsModifiable==`true`].{ParameterName:ParameterName, DefaultValue:ParameterValue}'

For Windows:

aws rds describe-engine-default-parameters ^ --db-parameter-group-family db2-se-11.5 ^ --query 'EngineDefaults.Parameters[?IsModifiable==`true`].{ParameterName:ParameterName, DefaultValue:ParameterValue}'

To view the parameter values for a DB parameter group, use the RDS API DescribeDBParameters command with the following required parameter.

  • DBParameterGroupName

Viewing all parameters with Db2 commands

You can view the settings for database manager configuration parameters, database configuration parameters, and registry variables by using Db2 commands.

To view the settings
  1. Connect to your Db2 database. In the following example, replace database_name, master_username, and master_password with your information.

    db2 "connect to database_name user master_username using master_password"
  2. Find the supported Db2 version.

    db2 "select service_level, fixpack_num from table(sysproc.env_get_inst_info()) as instanceinfo"
  3. View the parameters for a specific Db2 version.

    • View database manager configuration parameters by running the following command:

      db2 "select cast(substr(name,1,24) as varchar(24)) as name, case when value_flags = 'NONE' then '' else value_flags end flags, cast(substr(value,1,64) as varchar(64)) as current_value from sysibmadm.dbmcfg order by name asc with UR"
    • View all of your database configuration parameters by running the following command:

      db2 "select cast(substr(name,1,24) as varchar(24)) as name, case when value_flags = 'NONE' then '' else value_flags end flags, cast(substr(value,1,64) as varchar(64)) as current_value from table(db_get_cfg(null)) order by name asc, member asc with UR"
    • View the currently set registry variables by running the following command:

      db2 "select cast(substr(reg_var_name,1,50) as varchar(50)) as reg_var_name, cast(substr(reg_var_value,1,50) as varchar(50)) as reg_var_value, level from table(env_get_reg_variables(null)) order by reg_var_name,member with UR"

Modifying the parameters in parameter groups

You can modify the database manager configuration parameters and the registry variables in custom parameter groups by using the AWS Management Console, the AWS CLI, or the RDS API. For more information, see Working with DB parameter groups in a DB instance.

To modify database manager configuration parameters and registry variables
  1. Create a custom parameter group. For more information about creating a DB parameter group, see Creating a DB parameter group.

  2. Modify the parameters in that custom parameter group. For more information about modifying a parameter group, see Modifying parameters in a DB parameter group.

To modify database manager configuration parameters and registry variables
  1. Create a custom parameter group by running the create-db-parameter-group command.

    Include the following required options:

    • --db-parameter-group-name – A name for the parameter group that you are creating.

    • --db-parameter-group-family – The Db2 engine edition and major version. Valid values: db2-se-11.5, db2-ae-11.5.

    • --description – A description for this parameter group.

    For more information about creating a DB parameter group, see Creating a DB parameter group.

  2. Modify the parameters in the custom parameter group that you created by running the modify-db-parameter-group command.

    Include the following required options:

    • --db-parameter-group-name – The name of the parameter group that you created.

    • --parameters – An array of parameter names, values, and the application methods for the parameter update.

    For more information about modifying a parameter group, see Modifying parameters in a DB parameter group.

To modify database manager configuration parameters and registry variables
  1. Create a custom DB parameter group by using the CreateDBParameterGroup operation.

    Include the following required parameters:

    • DBParameterGroupName

    • DBParameterGroupFamily

    • Description

    For more information about creating a DB parameter group, see Creating a DB parameter group.

  2. Modify the parameters in the custom parameter group that you created by using the ModifyDBParameterGroup operation.

    Include the following required parameters:

    • DBParameterGroupName

    • Parameters

    For more information about modifying a parameter group, see Modifying parameters in a DB parameter group.

Modifying the database configuration parameters with Db2 commands

You can modify the database configuration parameters with Db2 commands.

To modify the database configuration parameters
  1. Connect to the rdsadmin database. In the following example, replace master_username and master_password with your information.

    db2 "connect to rdsadmin user master_username using master_password"
  2. Change the database configuration parameters by calling the rdsadmin.update_db_param stored procedure. For more information, see rdsadmin.update_db_param.

    db2 "call rdsadmin.update_db_param( 'database_name', 'parameter_to_modify', 'changed_value')"