# Parameter groups for Amazon RDS
*Database parameters* specify how the database is configured. For example, database parameters can specify the amount of resources, such as memory, to allocate to a database.
You manage your database configuration by associating your DB instances and Multi-AZ DB clusters with parameter groups. Amazon RDS defines parameter groups with default settings. You can also define your own parameter groups with customized settings.
**Note**
Some DB engines offer additional features that you can add to your database as options in an option group. For information about option groups, see [Working with option groups](USER_WorkingWithOptionGroups.md).
**Topics**
+ [
# Overview of parameter groups
](parameter-groups-overview.md)
+ [
# DB parameter groups for Amazon RDS DB instances
](USER_WorkingWithDBInstanceParamGroups.md)
+ [
# Working with DB cluster parameter groups for Multi-AZ DB clusters
](USER_WorkingWithDBClusterParamGroups.md)
+ [
# Comparing DB parameter groups
](USER_WorkingWithParamGroups.Comparing.md)
+ [
# Specifying DB parameters
](USER_ParamValuesRef.md)
# Overview of parameter groups
A *DB parameter group* acts as a container for engine configuration values that are applied to one or more DB instances.
*DB cluster parameter groups* apply to Multi-AZ DB clusters only. In a Multi-AZ DB cluster, the settings in the DB cluster parameter group apply to all of the DB instances in the cluster. The default DB parameter group for the DB engine and DB engine version is used for each DB instance in the DB cluster.
**Topics**
+ [
## Default and custom parameter groups
](#parameter-groups-overview.custom)
+ [
## Static and dynamic DB instance parameters
](#parameter-groups-overview.db-instance)
+ [
## Static and dynamic DB cluster parameters
](#parameter-groups-overview.maz)
+ [
## Character set parameters
](#parameter-groups-overview.char-sets)
+ [
## Supported parameters and parameter values
](#parameter-groups-overview.supported)
## Default and custom parameter groups
If you create a DB instance without specifying a DB parameter group, the DB instance uses a default DB parameter group. Likewise, if you create a Multi-AZ DB cluster without specifying a DB cluster parameter group, the DB cluster uses a default DB cluster parameter group. Each default parameter group contains database engine defaults and Amazon RDS system defaults based on the engine, compute class, and allocated storage of the instance.
You can't modify the parameter settings of a default parameter group. Instead, you can do the following:
1. Create a new parameter group.
1. Change the settings of your desired parameters. Not all DB engine parameters in a parameter group are eligible to be modified.
1. Modify your DB instance or DB cluster to associate the new parameter group.
When you associate a new DB parameter group with a DB instance, the association happens immediately. For information about modifying a DB instance, see [Modifying an Amazon RDS DB instance](Overview.DBInstance.Modifying.md). For information about modifying a Multi-AZ DB clusters, see [Modifying a Multi-AZ DB cluster for Amazon RDS](modify-multi-az-db-cluster.md).
**Note**
If you have modified your DB instance to use a custom parameter group, and you start the DB instance, RDS automatically reboots the DB instance as part of the startup process. For RDS for SQL Server Multi-AZ instances with AlwaysOn or Mirroring option enabled, a failover is expected when instance is rebooted after the startup process.
RDS applies the modified static and dynamic parameters in a newly associated parameter group only after the DB instance is rebooted. However, if you modify dynamic parameters in the DB parameter group after you associate it with the DB instance, these changes are applied immediately without a reboot. For more information about changing the DB parameter group, see [Modifying an Amazon RDS DB instance](Overview.DBInstance.Modifying.md).
If you update parameters within a DB parameter group, the changes apply to all DB instances that are associated with that parameter group. Likewise, if you update parameters within a Multi-AZ DB cluster parameter group, the changes apply to all Aurora DB clusters that are associated with that DB cluster parameter group.
If you don't want to create a parameter group from scratch, you can copy an existing parameter group with the AWS CLI [copy-db-parameter-group](https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-parameter-group.html) command or [copy-db-cluster-parameter-group](https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-cluster-parameter-group.html) command. You might find that copying a parameter group is useful in some cases. For example, you might want to include most of an existing DB parameter group's custom parameters and values in a new DB parameter group.
## Static and dynamic DB instance parameters
DB instance parameters are either static or dynamic. They differ as follows:
+ When you change a static parameter and save the DB parameter group, the parameter change takes effect after you manually reboot the associated DB instances. For static parameters, the console always uses `pending-reboot` for the `ApplyMethod`.
+ When you change a dynamic parameter, by default the parameter change takes effect immediately, without requiring a reboot. When you use the AWS Management Console to change DB instance parameter values, it always uses `immediate` for the `ApplyMethod` for dynamic parameters. To defer the parameter change until after you reboot an associated DB instance, use the AWS CLI or RDS API. Set the `ApplyMethod` to `pending-reboot` for the parameter change.
**Note**
Using `pending-reboot` with dynamic parameters in the AWS CLI or RDS API on RDS for SQL Server DB instances generates an error. Use `apply-immediately` on RDS for SQL Server.
For more information about using the AWS CLI to change a parameter value, see [modify-db-parameter-group](https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-parameter-group.html). For more information about using the RDS API to change a parameter value, see [ModifyDBParameterGroup](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBParameterGroup.html).
If a DB instance isn't using the latest changes to its associated DB parameter group, the console shows a status of **pending-reboot** for the DB parameter group. This status doesn't result in an automatic reboot during the next maintenance window. To apply the latest parameter changes to that DB instance, manually reboot the DB instance.
## Static and dynamic DB cluster parameters
DB cluster parameters are either static or dynamic. They differ as follows:
+ When you change a static parameter and save the DB cluster parameter group, the parameter change takes effect after you manually reboot the associated DB clusters. For static parameters, the console always uses `pending-reboot` for the `ApplyMethod`.
+ When you change a dynamic parameter, by default the parameter change takes effect immediately, without requiring a reboot. When you use the AWS Management Console to change DB cluster parameter values, it always uses `immediate` for the `ApplyMethod` for dynamic parameters. To defer the parameter change until after an associated DB cluster is rebooted, use the AWS CLI or RDS API. Set the `ApplyMethod` to `pending-reboot` for the parameter change.
For more information about using the AWS CLI to change a parameter value, see [modify-db-cluster-parameter-group](https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-cluster-parameter-group.html). For more information about using the RDS API to change a parameter value, see [ModifyDBClusterParameterGroup](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBClusterParameterGroup.html).
## Character set parameters
Before you create a DB instance or Multi-AZ DB cluster, set any parameters that relate to the character set or collation of your database in your parameter group. Also do so before you create a database in it. In this way, you ensure that the default database and new databases use the character set and collation values that you specify. If you change character set or collation parameters, the parameter changes aren't applied to existing databases.
For some DB engines, you can change character set or collation values for an existing database using the `ALTER DATABASE` command, for example:
```
ALTER DATABASE database_name CHARACTER SET character_set_name COLLATE collation;
```
For more information about changing the character set or collation values for a database, check the documentation for your DB engine.
## Supported parameters and parameter values
To determine the supported parameters for your DB engine, view the parameters in the DB parameter group and DB cluster parameter group used by the DB instance or DB cluster. For more information, see [Viewing parameter values for a DB parameter group in Amazon RDS](USER_WorkingWithParamGroups.Viewing.md) and [Viewing parameter values for a DB cluster parameter group](USER_WorkingWithParamGroups.ViewingCluster.md).
In many cases, you can specify integer and Boolean parameter values using expressions, formulas, and functions. Functions can include a mathematical log expression. However, not all parameters support expressions, formulas, and functions for parameter values. For more information, see [Specifying DB parameters](USER_ParamValuesRef.md).
Improperly setting parameters in a parameter group can have unintended adverse effects, including degraded performance and system instability. Always be cautious when modifying database parameters, and back up your data before modifying a parameter group. Try parameter group setting changes on a test DB instance or DB cluster before applying those parameter group changes to a production DB instance or DB cluster.
# DB parameter groups for Amazon RDS DB instances
DB instances use DB parameter groups. The following sections describe configuring and managing DB instance parameter groups.
**Topics**
+ [
# Creating a DB parameter group in Amazon RDS
](USER_WorkingWithParamGroups.Creating.md)
+ [
# Associating a DB parameter group with a DB instance in Amazon RDS
](USER_WorkingWithParamGroups.Associating.md)
+ [
# Modifying parameters in a DB parameter group in Amazon RDS
](USER_WorkingWithParamGroups.Modifying.md)
+ [
# Resetting parameters in a DB parameter group to their default values in Amazon RDS
](USER_WorkingWithParamGroups.Resetting.md)
+ [
# Copying a DB parameter group in Amazon RDS
](USER_WorkingWithParamGroups.Copying.md)
+ [
# Listing DB parameter groups in Amazon RDS
](USER_WorkingWithParamGroups.Listing.md)
+ [
# Viewing parameter values for a DB parameter group in Amazon RDS
](USER_WorkingWithParamGroups.Viewing.md)
+ [
# Deleting a DB parameter group in Amazon RDS
](USER_WorkingWithParamGroups.Deleting.md)
# Creating a DB parameter group in Amazon RDS
You can create a new DB parameter group using the AWS Management Console, the AWS CLI, or the RDS API.
The following limitations apply to the DB parameter group name:
+ The name must be 1 to 255 letters, numbers, or hyphens.
Default parameter group names can include a period, such as `default.mysql8.0`. However, custom parameter group names can't include a period.
+ The first character must be a letter.
+ The name can't end with a hyphen or contain two consecutive hyphens.
## Console
**To create 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/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. Choose **Create parameter group**.
1. For **Parameter group name**, enter the name of your new DB parameter group.
1. For **Description**, enter a description for your new DB parameter group.
1. For **Engine type**, choose your DB engine.
1. For **Parameter group family**, choose a DB parameter group family.
1. For **Type**, if applicable, choose **DB Parameter Group**.
1. Choose **Create**.
## AWS CLI
To create a DB parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/create-db-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/create-db-parameter-group.html) command. The following example creates a DB parameter group named *mydbparametergroup* for MySQL version 8.0 with a description of "*My new parameter group*."
Include the following required parameters:
+ `--db-parameter-group-name`
+ `--db-parameter-group-family`
+ `--description`
To list all of the available parameter group families, use the following command:
```
aws rds describe-db-engine-versions --query "DBEngineVersions[].DBParameterGroupFamily"
```
**Note**
The output contains duplicates.
**Example**
For Linux, macOS, or Unix:
```
aws rds create-db-parameter-group \
--db-parameter-group-name mydbparametergroup \
--db-parameter-group-family MySQL8.0 \
--description "My new parameter group"
```
For Windows:
```
aws rds create-db-parameter-group ^
--db-parameter-group-name mydbparametergroup ^
--db-parameter-group-family MySQL8.0 ^
--description "My new parameter group"
```
This command produces output similar to the following:
```
DBPARAMETERGROUP mydbparametergroup mysql8.0 My new parameter group
```
## RDS API
To create a DB parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CreateDBParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CreateDBParameterGroup.html) operation.
Include the following required parameters:
+ `DBParameterGroupName`
+ `DBParameterGroupFamily`
+ `Description`
# Associating a DB parameter group with a DB instance in Amazon RDS
You can create your own DB parameter groups with customized settings. You can associate a DB parameter group with a DB instance using the AWS Management Console, the AWS CLI, or the RDS API. You can do so when you create or modify a DB instance.
For information about creating a DB parameter group, see [Creating a DB parameter group in Amazon RDS](USER_WorkingWithParamGroups.Creating.md). For information about creating a DB instance, see [Creating an Amazon RDS DB instance](USER_CreateDBInstance.md). For information about modifying a DB instance, see [Modifying an Amazon RDS DB instance](Overview.DBInstance.Modifying.md).
**Note**
When you associate a new DB parameter group with a DB instance, the modified static and dynamic parameters are applied only after the DB instance is rebooted. However, if you modify dynamic parameters in the DB parameter group after you associate it with the DB instance, these changes are applied immediately without a reboot.
## Console
**To associate a DB parameter group with a DB instance**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Databases**, and then choose the DB instance that you want to modify.
1. Choose **Modify**. The **Modify DB instance** page appears.
1. Change the **DB parameter group** setting.
1. Choose **Continue** and check the summary of modifications.
1. (Optional) Choose **Apply immediately** to apply the changes immediately. Choosing this option can cause an outage in some cases. For more information, see [Using the schedule modifications setting](USER_ModifyInstance.ApplyImmediately.md).
1. On the confirmation page, review your changes. If they are correct, choose **Modify DB instance** to save your changes.
Or choose **Back** to edit your changes or **Cancel** to cancel your changes.
## AWS CLI
To associate a DB parameter group with a DB instance, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-instance.html](https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-instance.html) command with the following options:
+ `--db-instance-identifier`
+ `--db-parameter-group-name`
The following example associates the `mydbpg` DB parameter group with the `database-1` DB instance. The changes are applied immediately by using `--apply-immediately`. Use `--no-apply-immediately` to apply the changes during the next maintenance window. For more information, see [Using the schedule modifications setting](USER_ModifyInstance.ApplyImmediately.md).
**Example**
For Linux, macOS, or Unix:
```
aws rds modify-db-instance \
--db-instance-identifier database-1 \
--db-parameter-group-name mydbpg \
--apply-immediately
```
For Windows:
```
aws rds modify-db-instance ^
--db-instance-identifier database-1 ^
--db-parameter-group-name mydbpg ^
--apply-immediately
```
## RDS API
To associate a DB parameter group with a DB instance, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBInstance.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBInstance.html) operation with the following parameters:
+ `DBInstanceName`
+ `DBParameterGroupName`
# Modifying parameters in a DB parameter group in Amazon RDS
You can modify parameter values in a customer-created DB parameter group; you can't change the parameter values in a default DB parameter group. Changes to parameters in a customer-created DB parameter group are applied to all DB instances that are associated with the DB parameter group.
There are two types of parameters: dynamic parameters and static parameters. Changes to dynamic parameters are applied to the DB instance immediately without a reboot. Changes to static parameters are applied only after the DB instance is rebooted.
The RDS console shows the status of the DB parameter group associated with a DB instance on the **Configuration** tab. For example, if the DB instance isn't using the latest changes to its associated DB parameter group, the RDS console shows the DB parameter group with a status of **pending-reboot**. To apply the latest parameter changes to that DB instance, manually reboot the DB instance.
![\[Parameter change pending reboot scenario\]](http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/images/param-reboot.png)
## Console
**To modify the parameters in 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/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the name of the parameter group that you want to modify.
1. For **Parameter group actions**, choose **Edit**.
1. Change the values of the parameters that you want to modify. You can scroll through the parameters using the arrow keys at the top right of the dialog box.
You can't change values in a default parameter group.
1. Choose **Save changes**.
## AWS CLI
To modify a DB parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-parameter-group.html) command with the following required options:
+ `--db-parameter-group-name`
+ `--parameters`
The following example modifies the` max_connections` and `max_allowed_packet` values in the DB parameter group named *mydbparametergroup*.
**Example**
For Linux, macOS, or Unix:
```
aws rds modify-db-parameter-group \
--db-parameter-group-name mydbparametergroup \
--parameters "ParameterName=max_connections,ParameterValue=250,ApplyMethod=immediate" \
"ParameterName=max_allowed_packet,ParameterValue=1024,ApplyMethod=immediate"
```
For Windows:
```
aws rds modify-db-parameter-group ^
--db-parameter-group-name mydbparametergroup ^
--parameters "ParameterName=max_connections,ParameterValue=250,ApplyMethod=immediate" ^
"ParameterName=max_allowed_packet,ParameterValue=1024,ApplyMethod=immediate"
```
The command produces output like the following:
```
DBPARAMETERGROUP mydbparametergroup
```
## RDS API
To modify a DB parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBParameterGroup.html) operation with the following required parameters:
+ `DBParameterGroupName`
+ `Parameters`
# Resetting parameters in a DB parameter group to their default values in Amazon RDS
You can reset parameter values in a customer-created DB parameter group to their default values. Changes to parameters in a customer-created DB parameter group are applied to all DB instances that are associated with the DB parameter group.
When you use the console, you can reset specific parameters to their default values. However, you can't easily reset all of the parameters in the DB parameter group at once. When you use the AWS CLI or RDS API, you can reset specific parameters to their default values. You can also reset all of the parameters in the DB parameter group at once.
Changes to some parameters are applied to the DB instance immediately without a reboot. Changes to other parameters are applied only after the DB instance is rebooted. The RDS console shows the status of the DB parameter group associated with a DB instance on the **Configuration** tab. For example, suppose that the DB instance isn't using the latest changes to its associated DB parameter group. If so, the RDS console shows the DB parameter group with a status of **pending-reboot**. To apply the latest parameter changes to that DB instance, manually reboot the DB instance.
![\[Parameter change pending reboot scenario\]](http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/images/param-reboot.png)
**Note**
In a default DB parameter group, parameters are always set to their default values.
## Console
**To reset parameters in a DB parameter group to their default values**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the parameter group.
1. For **Parameter group actions**, choose **Edit**.
1. Choose the parameters that you want to reset to their default values. You can scroll through the parameters using the arrow keys at the top right of the dialog box.
You can't reset values in a default parameter group.
1. Choose **Reset** and then confirm by choosing **Reset parameters**.
## AWS CLI
To reset some or all of the parameters in a DB parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/reset-db-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/reset-db-parameter-group.html) command with the following required option: `--db-parameter-group-name`.
To reset all of the parameters in the DB parameter group, specify the `--reset-all-parameters` option. To reset specific parameters, specify the `--parameters` option.
The following example resets all of the parameters in the DB parameter group named *mydbparametergroup* to their default values.
**Example**
For Linux, macOS, or Unix:
```
aws rds reset-db-parameter-group \
--db-parameter-group-name mydbparametergroup \
--reset-all-parameters
```
For Windows:
```
aws rds reset-db-parameter-group ^
--db-parameter-group-name mydbparametergroup ^
--reset-all-parameters
```
The following example resets the `max_connections` and `max_allowed_packet` options to their default values in the DB parameter group named *mydbparametergroup*.
**Example**
For Linux, macOS, or Unix:
```
aws rds reset-db-parameter-group \
--db-parameter-group-name mydbparametergroup \
--parameters "ParameterName=max_connections,ApplyMethod=immediate" \
"ParameterName=max_allowed_packet,ApplyMethod=immediate"
```
For Windows:
```
aws rds reset-db-parameter-group ^
--db-parameter-group-name mydbparametergroup ^
--parameters "ParameterName=max_connections,ApplyMethod=immediate" ^
"ParameterName=max_allowed_packet,ApplyMethod=immediate"
```
The command produces output like the following:
```
DBParameterGroupName mydbparametergroup
```
## RDS API
To reset parameters in a DB parameter group to their default values, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ResetDBParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ResetDBParameterGroup.html) command with the following required parameter: `DBParameterGroupName`.
To reset all of the parameters in the DB parameter group, set the `ResetAllParameters` parameter to `true`. To reset specific parameters, specify the `Parameters` parameter.
# Copying a DB parameter group in Amazon RDS
You can copy custom DB parameter groups that you create. Copying a parameter group can be convenient solution. An example is when you have created a DB parameter group and want to include most of its custom parameters and values in a new DB parameter group. You can copy a DB parameter group by using the AWS Management Console. You can also use the AWS CLI [copy-db-parameter-group](https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-parameter-group.html) command or the RDS API [CopyDBParameterGroup](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CopyDBParameterGroup.html) operation.
After you copy a DB parameter group, wait at least 5 minutes before creating your first DB instance that uses that DB parameter group as the default parameter group. Doing this allows Amazon RDS to fully complete the copy action before the parameter group is used. This is especially important for parameters that are critical when creating the default database for a DB instance. An example is the character set for the default database defined by the `character_set_database` parameter. Use the **Parameter Groups** option of the [Amazon RDS console](https://console.aws.amazon.com/rds/) or the [describe-db-parameters](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-parameters.html) command to verify that your DB parameter group is created.
**Note**
You can't copy a default parameter group. However, you can create a new parameter group that is based on a default parameter group.
You can't copy a DB parameter group to a different AWS account or AWS Region.
## Console
**To copy 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/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the custom parameter group that you want to copy.
1. For **Parameter group actions**, choose **Copy**.
1. In **New DB parameter group identifier**, enter a name for the new parameter group.
1. In **Description**, enter a description for the new parameter group.
1. Choose **Copy**.
## AWS CLI
To copy a DB parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-parameter-group.html) command with the following required options:
+ `--source-db-parameter-group-identifier`
+ `--target-db-parameter-group-identifier`
+ `--target-db-parameter-group-description`
The following example creates a new DB parameter group named `mygroup2` that is a copy of the DB parameter group `mygroup1`.
**Example**
For Linux, macOS, or Unix:
```
aws rds copy-db-parameter-group \
--source-db-parameter-group-identifier mygroup1 \
--target-db-parameter-group-identifier mygroup2 \
--target-db-parameter-group-description "DB parameter group 2"
```
For Windows:
```
aws rds copy-db-parameter-group ^
--source-db-parameter-group-identifier mygroup1 ^
--target-db-parameter-group-identifier mygroup2 ^
--target-db-parameter-group-description "DB parameter group 2"
```
## RDS API
To copy a DB parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CopyDBParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CopyDBParameterGroup.html) operation with the following required parameters:
+ `SourceDBParameterGroupIdentifier`
+ `TargetDBParameterGroupIdentifier`
+ `TargetDBParameterGroupDescription`
# Listing DB parameter groups in Amazon RDS
You can list the DB parameter groups you've created for your AWS account.
**Note**
Default parameter groups are automatically created from a default parameter template when you create a DB instance for a particular DB engine and version. These default parameter groups contain preferred parameter settings and can't be modified. When you create a custom parameter group, you can modify parameter settings.
## Console
**To list all DB parameter groups for an AWS account**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
The DB parameter groups appear in a list.
## AWS CLI
To list all DB parameter groups for an AWS account, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-parameter-groups.html](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-parameter-groups.html) command.
**Example**
The following example lists all available DB parameter groups for an AWS account.
```
aws rds describe-db-parameter-groups
```
The command returns a response like the following:
```
DBPARAMETERGROUP default.mysql8.0 mysql8.0 Default parameter group for MySQL8.0
DBPARAMETERGROUP mydbparametergroup mysql8.0 My new parameter group
```
The following example describes the *mydbparamgroup1* parameter group.
For Linux, macOS, or Unix:
```
aws rds describe-db-parameter-groups \
--db-parameter-group-name mydbparamgroup1
```
For Windows:
```
aws rds describe-db-parameter-groups ^
--db-parameter-group-name mydbparamgroup1
```
The command returns a response like the following:
```
DBPARAMETERGROUP mydbparametergroup1 mysql8.0 My new parameter group
```
## RDS API
To list all DB parameter groups for an AWS account, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBParameterGroups.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBParameterGroups.html) operation.
# Viewing parameter values for a DB parameter group in Amazon RDS
You can get a list of all parameters in a DB parameter group and their values.
## Console
**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/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
The DB parameter groups appear in a list.
1. Choose the name of the parameter group to see its list of parameters.
## AWS CLI
To view the parameter values for a DB parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-parameters.html](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-parameters.html) command with the following required parameter.
+ `--db-parameter-group-name`
**Example**
The following example lists the parameters and parameter values for a DB parameter group named *mydbparametergroup.*
```
aws rds describe-db-parameters --db-parameter-group-name mydbparametergroup
```
The command returns a response like the following:
```
DBPARAMETER Parameter Name Parameter Value Source Data Type Apply Type Is Modifiable
DBPARAMETER allow-suspicious-udfs engine-default boolean static false
DBPARAMETER auto_increment_increment engine-default integer dynamic true
DBPARAMETER auto_increment_offset engine-default integer dynamic true
DBPARAMETER binlog_cache_size 32768 system integer dynamic true
DBPARAMETER socket /tmp/mysql.sock system string static false
```
## RDS API
To view the parameter values for a DB parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBParameters.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBParameters.html) command with the following required parameter.
+ `DBParameterGroupName`
# Deleting a DB parameter group in Amazon RDS
You can delete a DB parameter group using the AWS Management Console, AWS CLI, or RDS API. A parameter group is eligible for deletion only if it isn't associated with a DB instance.
## Console
**To delete 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/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
The DB parameter groups appear in a list.
1. Choose the name of the parameter groups to be deleted.
1. Choose **Actions** and then **Delete**.
1. Review the parameter group names and then choose **Delete**.
## AWS CLI
To delete a DB parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/delete-db-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/delete-db-parameter-group.html) command with the following required parameter.
+ `--db-parameter-group-name`
**Example**
The following example deletes a DB parameter group named *mydbparametergroup.*
```
aws rds delete-db-parameter-group --db-parameter-group-name mydbparametergroup
```
## RDS API
To delete a DB parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DeleteDBParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DeleteDBParameterGroup.html) command with the following required parameter.
+ `DBParameterGroupName`
# Working with DB cluster parameter groups for Multi-AZ DB clusters
Multi-AZ DB clusters use DB cluster parameter groups. The following sections describe configuring and managing DB cluster parameter groups.
**Topics**
+ [
# Creating a DB cluster parameter group
](USER_WorkingWithParamGroups.CreatingCluster.md)
+ [
# Modifying parameters in a DB cluster parameter group
](USER_WorkingWithParamGroups.ModifyingCluster.md)
+ [
# Resetting parameters in a DB cluster parameter group
](USER_WorkingWithParamGroups.ResettingCluster.md)
+ [
# Copying a DB cluster parameter group
](USER_WorkingWithParamGroups.CopyingCluster.md)
+ [
# Listing DB cluster parameter groups
](USER_WorkingWithParamGroups.ListingCluster.md)
+ [
# Viewing parameter values for a DB cluster parameter group
](USER_WorkingWithParamGroups.ViewingCluster.md)
+ [
# Deleting a DB cluster parameter group
](USER_WorkingWithParamGroups.DeletingCluster.md)
# Creating a DB cluster parameter group
You can create a new DB cluster parameter group using the AWS Management Console, the AWS CLI, or the RDS API.
After you create a DB cluster parameter group, wait at least 5 minutes before creating a DB cluster that uses that DB cluster parameter group. Doing this allows Amazon RDS to fully create the parameter group before it is used by the new DB cluster. You can use the **Parameter groups** page in the [Amazon RDS console](https://console.aws.amazon.com/rds/) or the [describe-db-cluster-parameters](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-cluster-parameters.html) command to verify that your DB cluster parameter group is created.
The following limitations apply to the DB cluster parameter group name:
+ The name must be 1 to 255 letters, numbers, or hyphens.
Default parameter group names can include a period, such as `default.mysql5.7`. However, custom parameter group names can't include a period.
+ The first character must be a letter.
+ The name can't end with a hyphen or contain two consecutive hyphens.
## Console
**To create a DB cluster parameter group**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. Choose **Create parameter group**.
1. For **Parameter group name**, enter the name of the new DB cluster parameter group.
1. For **Description**, enter a description for the new DB cluster parameter group.
1. For **Engine type**, choose your database engine.
1. For **Parameter group family**, choose a DB parameter group family.
1. Choose **Create**.
## AWS CLI
To create a DB cluster parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/create-db-cluster-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/create-db-cluster-parameter-group.html) command.
The following example creates a DB cluster parameter group named *mydbclusterparametergroup* for RDS for MySQL version 8.0 with a description of "*My new cluster parameter group*."
Include the following required parameters:
+ `--db-cluster-parameter-group-name`
+ `--db-parameter-group-family`
+ `--description`
To list all of the available parameter group families, use the following command:
```
aws rds describe-db-engine-versions --query "DBEngineVersions[].DBParameterGroupFamily"
```
**Note**
The output contains duplicates.
**Example**
For Linux, macOS, or Unix:
```
aws rds create-db-cluster-parameter-group \
--db-cluster-parameter-group-name mydbclusterparametergroup \
--db-parameter-group-family mysql8.0 \
--description "My new cluster parameter group"
```
For Windows:
```
aws rds create-db-cluster-parameter-group ^
--db-cluster-parameter-group-name mydbclusterparametergroup ^
--db-parameter-group-family mysql8.0 ^
--description "My new cluster parameter group"
```
This command produces output similar to the following:
```
{
"DBClusterParameterGroup": {
"DBClusterParameterGroupName": "mydbclusterparametergroup",
"DBParameterGroupFamily": "mysql8.0",
"Description": "My new cluster parameter group",
"DBClusterParameterGroupArn": "arn:aws:rds:us-east-1:123456789012:cluster-pg:mydbclusterparametergroup2"
}
}
```
## RDS API
To create a DB cluster parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CreateDBClusterParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CreateDBClusterParameterGroup.html) action.
Include the following required parameters:
+ `DBClusterParameterGroupName`
+ `DBParameterGroupFamily`
+ `Description`
# Modifying parameters in a DB cluster parameter group
You can modify parameter values in a customer-created DB cluster parameter group. You can't change the parameter values in a default DB cluster parameter group. Changes to parameters in a customer-created DB cluster parameter group are applied to all DB clusters that are associated with the DB cluster parameter group.
## Console
**To modify a DB cluster parameter group**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the parameter group that you want to modify.
1. For **Parameter group actions**, choose **Edit**.
1. Change the values of the parameters you want to modify. You can scroll through the parameters using the arrow keys at the top right of the dialog box.
You can't change values in a default parameter group.
1. Choose **Save changes**.
1. Reboot the cluster to apply the changes to it.
If you don't reboot the cluster, then a failover operation could take longer than normal.
## AWS CLI
To modify a DB cluster parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-cluster-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-cluster-parameter-group.html) command with the following required parameters:
+ `--db-cluster-parameter-group-name`
+ `--parameters`
The following example modifies the `server_audit_logging` and `server_audit_logs_upload` values in the DB cluster parameter group named *mydbclusterparametergroup*.
**Example**
For Linux, macOS, or Unix:
```
aws rds modify-db-cluster-parameter-group \
--db-cluster-parameter-group-name mydbclusterparametergroup \
--parameters "ParameterName=server_audit_logging,ParameterValue=1,ApplyMethod=immediate" \
"ParameterName=server_audit_logs_upload,ParameterValue=1,ApplyMethod=immediate"
```
For Windows:
```
aws rds modify-db-cluster-parameter-group ^
--db-cluster-parameter-group-name mydbclusterparametergroup ^
--parameters "ParameterName=server_audit_logging,ParameterValue=1,ApplyMethod=immediate" ^
"ParameterName=server_audit_logs_upload,ParameterValue=1,ApplyMethod=immediate"
```
The command produces output like the following:
```
DBCLUSTERPARAMETERGROUP mydbclusterparametergroup
```
## RDS API
To modify a DB cluster parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBClusterParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBClusterParameterGroup.html) command with the following required parameters:
+ `DBClusterParameterGroupName`
+ `Parameters`
# Resetting parameters in a DB cluster parameter group
You can reset parameters to their default values in a customer-created DB cluster parameter group. Changes to parameters in a customer-created DB cluster parameter group are applied to all DB clusters that are associated with the DB cluster parameter group.
**Note**
In a default DB cluster parameter group, parameters are always set to their default values.
## Console
**To reset parameters in a DB cluster parameter group to their default values**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the parameter group.
1. For **Parameter group actions**, choose **Edit**.
1. Choose the parameters that you want to reset to their default values. You can scroll through the parameters using the arrow keys at the top right of the dialog box.
You can't reset values in a default parameter group.
1. Choose **Reset** and then confirm by choosing **Reset parameters**.
1. Reboot the DB cluster.
## AWS CLI
To reset parameters in a DB cluster parameter group to their default values, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/reset-db-cluster-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/reset-db-cluster-parameter-group.html) command with the following required option: `--db-cluster-parameter-group-name`.
To reset all of the parameters in the DB cluster parameter group, specify the `--reset-all-parameters` option. To reset specific parameters, specify the `--parameters` option.
The following example resets all of the parameters in the DB parameter group named *mydbparametergroup* to their default values.
**Example**
For Linux, macOS, or Unix:
```
aws rds reset-db-cluster-parameter-group \
--db-cluster-parameter-group-name mydbparametergroup \
--reset-all-parameters
```
For Windows:
```
aws rds reset-db-cluster-parameter-group ^
--db-cluster-parameter-group-name mydbparametergroup ^
--reset-all-parameters
```
The following example resets the `server_audit_logging` and `server_audit_logs_upload` to their default values in the DB cluster parameter group named *mydbclusterparametergroup*.
**Example**
For Linux, macOS, or Unix:
```
aws rds reset-db-cluster-parameter-group \
--db-cluster-parameter-group-name mydbclusterparametergroup \
--parameters "ParameterName=server_audit_logging,ApplyMethod=immediate" \
"ParameterName=server_audit_logs_upload,ApplyMethod=immediate"
```
For Windows:
```
aws rds reset-db-cluster-parameter-group ^
--db-cluster-parameter-group-name mydbclusterparametergroup ^
--parameters "ParameterName=server_audit_logging,ParameterValue=1,ApplyMethod=immediate" ^
"ParameterName=server_audit_logs_upload,ParameterValue=1,ApplyMethod=immediate"
```
The command produces output like the following:
```
DBClusterParameterGroupName mydbclusterparametergroup
```
## RDS API
To reset parameters in a DB cluster parameter group to their default values, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ResetDBClusterParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ResetDBClusterParameterGroup.html) command with the following required parameter: `DBClusterParameterGroupName`.
To reset all of the parameters in the DB cluster parameter group, set the `ResetAllParameters` parameter to `true`. To reset specific parameters, specify the `Parameters` parameter.
# Copying a DB cluster parameter group
You can copy custom DB cluster parameter groups that you create. Copying a parameter group is a convenient solution when you have already created a DB cluster parameter group and you want to include most of the custom parameters and values from that group in a new DB cluster parameter group. You can copy a DB cluster parameter group by using the AWS CLI [copy-db-cluster-parameter-group](https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-cluster-parameter-group.html) command or the RDS API [CopyDBClusterParameterGroup](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CopyDBParameterGroup.html) operation.
After you copy a DB cluster parameter group, wait at least 5 minutes before creating a DB cluster that uses that DB cluster parameter group. Doing this allows Amazon RDS to fully copy the parameter group before it is used by the new DB cluster. You can use the **Parameter groups** page in the [Amazon RDS console](https://console.aws.amazon.com/rds/) or the [describe-db-cluster-parameters](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-cluster-parameters.html) command to verify that your DB cluster parameter group is created.
**Note**
You can't copy a default parameter group. However, you can create a new parameter group that is based on a default parameter group.
You can't copy a DB cluster parameter group to a different AWS account or AWS Region.
## Console
**To copy a DB cluster parameter group**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the custom parameter group that you want to copy.
1. For **Parameter group actions**, choose **Copy**.
1. In **New DB parameter group identifier**, enter a name for the new parameter group.
1. In **Description**, enter a description for the new parameter group.
1. Choose **Copy**.
## AWS CLI
To copy a DB cluster parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-cluster-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/copy-db-cluster-parameter-group.html) command with the following required parameters:
+ `--source-db-cluster-parameter-group-identifier`
+ `--target-db-cluster-parameter-group-identifier`
+ `--target-db-cluster-parameter-group-description`
The following example creates a new DB cluster parameter group named `mygroup2` that is a copy of the DB cluster parameter group `mygroup1`.
**Example**
For Linux, macOS, or Unix:
```
aws rds copy-db-cluster-parameter-group \
--source-db-cluster-parameter-group-identifier mygroup1 \
--target-db-cluster-parameter-group-identifier mygroup2 \
--target-db-cluster-parameter-group-description "DB parameter group 2"
```
For Windows:
```
aws rds copy-db-cluster-parameter-group ^
--source-db-cluster-parameter-group-identifier mygroup1 ^
--target-db-cluster-parameter-group-identifier mygroup2 ^
--target-db-cluster-parameter-group-description "DB parameter group 2"
```
## RDS API
To copy a DB cluster parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CopyDBClusterParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CopyDBClusterParameterGroup.html) operation with the following required parameters:
+ `SourceDBClusterParameterGroupIdentifier`
+ `TargetDBClusterParameterGroupIdentifier`
+ `TargetDBClusterParameterGroupDescription`
# Listing DB cluster parameter groups
You can list the DB cluster parameter groups you've created for your AWS account.
**Note**
Default parameter groups are automatically created from a default parameter template when you create a DB cluster for a particular DB engine and version. These default parameter groups contain preferred parameter settings and can't be modified. When you create a custom parameter group, you can modify parameter settings.
## Console
**To list all DB cluster parameter groups for an AWS account**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
The DB cluster parameter groups appear in the list with **DB cluster parameter group** for **Type**.
## AWS CLI
To list all DB cluster parameter groups for an AWS account, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-clusterparameter-groups.html](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-clusterparameter-groups.html) command.
**Example**
The following example lists all available DB cluster parameter groups for an AWS account.
```
aws rds describe-db-cluster-parameter-groups
```
The following example describes the *mydbclusterparametergroup* parameter group.
For Linux, macOS, or Unix:
```
aws rds describe-db-cluster-parameter-groups \
--db-cluster-parameter-group-name mydbclusterparametergroup
```
For Windows:
```
aws rds describe-db-cluster-parameter-groups ^
--db-cluster-parameter-group-name mydbclusterparametergroup
```
The command returns a response like the following:
```
{
"DBClusterParameterGroups": [
{
"DBClusterParameterGroupName": "mydbclusterparametergroup2",
"DBParameterGroupFamily": "mysql8.0",
"Description": "My new cluster parameter group",
"DBClusterParameterGroupArn": "arn:aws:rds:us-east-1:123456789012:cluster-pg:mydbclusterparametergroup"
}
]
}
```
## RDS API
To list all DB cluster parameter groups for an AWS account, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBClusterParameterGroups.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBClusterParameterGroups.html) action.
# Viewing parameter values for a DB cluster parameter group
You can get a list of all parameters in a DB cluster parameter group and their values.
## Console
**To view the parameter values for a DB cluster parameter group**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
The DB cluster parameter groups appear in the list with **DB cluster parameter group** for **Type**.
1. Choose the name of the DB cluster parameter group to see its list of parameters.
## AWS CLI
To view the parameter values for a DB cluster parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-cluster-parameters.html](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-cluster-parameters.html) command with the following required parameter.
+ `--db-cluster-parameter-group-name`
**Example**
The following example lists the parameters and parameter values for a DB cluster parameter group named *mydbclusterparametergroup*, in JSON format.
The command returns a response like the following:
```
aws rds describe-db-cluster-parameters --db-cluster-parameter-group-name mydbclusterparametergroup
```
```
{
"Parameters": [
{
"ParameterName": "activate_all_roles_on_login",
"ParameterValue": "0",
"Description": "Automatically set all granted roles as active after the user has authenticated successfully.",
"Source": "engine-default",
"ApplyType": "dynamic",
"DataType": "boolean",
"AllowedValues": "0,1",
"IsModifiable": true,
"ApplyMethod": "pending-reboot",
"SupportedEngineModes": [
"provisioned"
]
},
{
"ParameterName": "allow-suspicious-udfs",
"Description": "Controls whether user-defined functions that have only an xxx symbol for the main function can be loaded",
"Source": "engine-default",
"ApplyType": "static",
"DataType": "boolean",
"AllowedValues": "0,1",
"IsModifiable": false,
"ApplyMethod": "pending-reboot",
"SupportedEngineModes": [
"provisioned"
]
},
...
```
## RDS API
To view the parameter values for a DB cluster parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBParameters.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeDBParameters.html) command with the following required parameter.
+ `DBClusterParameterGroupName`
In some cases, the allowed values for a parameter aren't shown. These are always parameters where the source is the database engine default.
To view the values of these parameters, you can run the following SQL statements:
+ MySQL:
```
-- Show the value of a particular parameter
mysql$ SHOW VARIABLES LIKE '%parameter_name%';
-- Show the values of all parameters
mysql$ SHOW VARIABLES;
```
+ PostgreSQL:
```
-- Show the value of a particular parameter
postgresql=> SHOW parameter_name;
-- Show the values of all parameters
postgresql=> SHOW ALL;
```
# Deleting a DB cluster parameter group
You can delete a DB cluster parameter group using the AWS Management Console, AWS CLI, or RDS API. A DB cluster parameter group parameter group is eligible for deletion only if it isn't associated with a DB cluster.
## Console
**To delete parameter groups**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
The parameter groups appear in a list.
1. Choose the name of the DB cluster parameter groups to be deleted.
1. Choose **Actions** and then **Delete**.
1. Review the parameter group names and then choose **Delete**.
## AWS CLI
To delete a DB cluster parameter group, use the AWS CLI [https://docs.aws.amazon.com/cli/latest/reference/rds/delete-db-cluster-parameter-group.html](https://docs.aws.amazon.com/cli/latest/reference/rds/delete-db-cluster-parameter-group.html) command with the following required parameter.
+ `--db-parameter-group-name`
**Example**
The following example deletes a DB cluster parameter group named *mydbparametergroup.*
```
aws rds delete-db-cluster-parameter-group --db-parameter-group-name mydbparametergroup
```
## RDS API
To delete a DB cluster parameter group, use the RDS API [https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DeleteDBClusterParameterGroup.html](https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DeleteDBClusterParameterGroup.html) command with the following required parameter.
+ `DBParameterGroupName`
# Comparing DB parameter groups
You can use the AWS Management Console to view the differences between two DB parameter groups.
The specified parameter groups must both be DB parameter groups, or they both must be DB cluster parameter groups. This is true even when the DB engine and version are the same. For example, you can't compare an `aurora-mysql8.0` (Aurora MySQL version 3) DB parameter group and an `aurora-mysql8.0` DB cluster parameter group.
You can compare Aurora MySQL and RDS for MySQL DB parameter groups, even for different versions, but you can't compare Aurora PostgreSQL and RDS for PostgreSQL DB parameter groups.
**To compare two DB parameter groups**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Parameter groups**.
1. In the list, choose the two parameter groups that you want to compare.
**Note**
To compare a default parameter group to a custom parameter group, first choose the default parameter group on the **Default** tab, then choose the custom parameter group on the **Custom** tab.
1. From **Actions**, choose **Compare**.
# Specifying DB parameters
DB parameter types include the following:
+ Integer
+ Boolean
+ String
+ Long
+ Double
+ Timestamp
+ Object of other defined data types
+ Array of values of type integer, Boolean, string, long, double, timestamp, or object
You can also specify integer and Boolean parameters using expressions, formulas, and functions.
For the Oracle engine, you can use the `DBInstanceClassHugePagesDefault` formula variable to specify a Boolean DB parameter. See [DB parameter formula variables](#USER_FormulaVariables).
For the PostgreSQL engine, you can use an expression to specify a Boolean DB parameter. See [Boolean DB parameter expressions](#USER_ParamBooleanExpressions).
**Contents**
+ [
## DB parameter formulas
](#USER_ParamFormulas)
+ [
### DB parameter formula variables
](#USER_FormulaVariables)
+ [
### DB parameter formula operators
](#USER_FormulaOperators)
+ [
## DB parameter functions
](#USER_ParamFunctions)
+ [
## Boolean DB parameter expressions
](#USER_ParamBooleanExpressions)
+ [
## DB parameter log expressions
](#USER_ParamLogExpressions)
+ [
## DB parameter value examples
](#USER_ParamValueExamples)
## DB parameter formulas
A DB parameter formula is an expression that resolves to an integer value or a Boolean value. You enclose the expression in braces: \$1\$1. You can use a formula for either a DB parameter value or as an argument to a DB parameter function.
**Syntax**
```
{FormulaVariable}
{FormulaVariable*Integer}
{FormulaVariable*Integer/Integer}
{FormulaVariable/Integer}
```
### DB parameter formula variables
Each formula variable returns an integer or a Boolean value. The names of the variables are case-sensitive.
*AllocatedStorage*
Returns an integer representing the size, in bytes, of the data volume.
*DBInstanceClassHugePagesDefault*
Returns a Boolean value. Currently, it's only supported for Oracle engines.
For more information, see [Turning on HugePages for an RDS for Oracle instance](Oracle.Concepts.HugePages.md).
*DBInstanceClassMemory*
Returns an integer for the number of bytes of memory available to the database process. This number is internally calculated by starting with the total amount of memory for the DB instance class. From this, the calculation subtracts memory reserved for the operating system and the RDS processes that manage the instance. Therefore, the number is always somewhat lower than the memory figures shown in the instance class tables in [DB instance classes](Concepts.DBInstanceClass.md). The exact value depends on a combination of factors. These include instance class, DB engine, and whether it applies to an RDS instance or an instance that's part of an Aurora cluster.
*DBInstanceVCPU*
Returns an integer representing the number of virtual central processing units (vCPUs) used by Amazon RDS to manage the instance.
*EndPointPort*
Returns an integer representing the port used when connecting to the DB instance.
*TrueIfReplica*
Returns `1` if the DB instance is a read replica and `0` if it is not. This is the default value for the `read_only` parameter in MySQL.
### DB parameter formula operators
DB parameter formulas support two operators: division and multiplication.
*Division operator: /*
Divides the dividend by the divisor, returning an integer quotient. Decimals in the quotient are truncated, not rounded.
Syntax
```
dividend / divisor
```
The dividend and divisor arguments must be integer expressions.
*Multiplication operator: \$1*
Multiplies the expressions, returning the product of the expressions. Decimals in the expressions are truncated, not rounded.
Syntax
```
expression * expression
```
Both expressions must be integers.
## DB parameter functions
You specify the arguments of DB parameter functions as either integers or formulas. Each function must have at least one argument. Specify multiple arguments as a comma-separated list. The list can't have any empty members, such as *argument1*,,*argument3*. Function names are case-insensitive.
*IF*
Returns an argument.
Currently, it's only supported for Oracle engines, and the only supported first argument is `{DBInstanceClassHugePagesDefault}`. For more information, see [Turning on HugePages for an RDS for Oracle instance](Oracle.Concepts.HugePages.md).
Syntax
```
IF(argument1, argument2, argument3)
```
Returns the second argument if the first argument evaluates to true. Returns the third argument otherwise.
*GREATEST*
Returns the largest value from a list of integers or parameter formulas.
Syntax
```
GREATEST(argument1, argument2,...argumentn)
```
Returns an integer.
*LEAST*
Returns the smallest value from a list of integers or parameter formulas.
Syntax
```
LEAST(argument1, argument2,...argumentn)
```
Returns an integer.
*SUM*
Adds the values of the specified integers or parameter formulas.
Syntax
```
SUM(argument1, argument2,...argumentn)
```
Returns an integer.
## Boolean DB parameter expressions
A Boolean DB parameter expression resolves to a Boolean value of 1 or 0. The expression is enclosed in quotation marks.
**Note**
Boolean DB parameter expressions are only supported for the PostgreSQL engine.
**Syntax**
```
"expression operator expression"
```
Both expressions must resolve to integers. An expression can be the following:
+ integer constant
+ DB parameter formula
+ DB parameter function
+ DB parameter variable
Boolean DB parameter expressions support the following inequality operators:
*The greater than operator: >*
Syntax
```
"expression > expression"
```
*The less than operator: <*
Syntax
```
"expression < expression"
```
* The greater than or equal to operators: >=, =>*
Syntax
```
"expression >= expression"
"expression => expression"
```
*The less than or equal to operators: <=, =<*
Syntax
```
"expression <= expression"
"expression =< expression"
```
**Example using a Boolean DB parameter expression**
The following Boolean DB parameter expression example compares the result of a parameter formula with an integer. It does so to modify the Boolean DB parameter `wal_compression` for a PostgreSQL DB instance. The parameter expression compares the number of vCPUs with the value 2. If the number of vCPUs is greater than 2, then the `wal_compression` DB parameter is set to true.
```
aws rds modify-db-parameter-group --db-parameter-group-name group-name \
--parameters "ParameterName=wal_compression,ParameterValue=\"{DBInstanceVCPU} > 2\" "
```
## DB parameter log expressions
You can set an integer DB parameter value to a log expression. You enclose the expression in braces: \$1\$1. For example:
```
{log(DBInstanceClassMemory/8187281418)*1000}
```
The `log` function represents log base 2. This example also uses the `DBInstanceClassMemory` formula variable. See [DB parameter formula variables](#USER_FormulaVariables).
**Note**
Currently, you can't specify the MySQL `innodb_log_file_size` parameter with any value other than an integer.
## DB parameter value examples
These examples show using formulas, functions, and expressions for the values of DB parameters.
**Warning**
Improperly setting parameters in a DB parameter group can have unintended adverse effects. These might include degraded performance and system instability. Use caution when modifying database parameters and back up your data before modifying your DB parameter group. Try out parameter group changes on a test DB instance, created using point-in-time-restores, before applying those parameter group changes to your production DB instances.
**Example using the DB parameter function GREATEST**
You can specify the `GREATEST` function in an Oracle processes parameter. Use it to set the number of user processes to the larger of either 80 or `DBInstanceClassMemory` divided by 9,868,951.
```
GREATEST({DBInstanceClassMemory/9868951},80)
```
**Example using the DB parameter function LEAST**
You can specify the `LEAST` function in a MySQL `max_binlog_cache_size` parameter value. Use it to set the maximum cache size a transaction can use in a MySQL instance to the lesser of 1 MB or `DBInstanceClass`/256.
```
LEAST({DBInstanceClassMemory/256},10485760)
```