> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/terraform-aws-modules/terraform-aws-rds/llms.txt
> Use this file to discover all available pages before exploring further.

# db_parameter_group submodule

> Reference for the db_parameter_group submodule, which provisions an aws_db_parameter_group resource.

The `db_parameter_group` submodule creates an `aws_db_parameter_group` for a specific engine family. Parameter groups let you manage database engine settings across one or more DB instances.

## Source

```
./modules/db_parameter_group
```

## Usage

Use this submodule standalone when you want to share a parameter group across multiple DB instances or manage parameters outside the lifecycle of a single DB instance:

```hcl theme={null}
module "db_parameter_group" {
  source  = "terraform-aws-modules/rds/aws//modules/db_parameter_group"
  version = "~> 7.0"

  name            = "mysql80-production"
  use_name_prefix = false
  description     = "MySQL 8.0 parameter group for production workloads"
  family          = "mysql8.0"

  parameters = [
    {
      name  = "character_set_client"
      value = "utf8mb4"
    },
    {
      name  = "character_set_server"
      value = "utf8mb4"
    },
    {
      name         = "max_connections"
      value        = "500"
      apply_method = "immediate"
    },
    {
      name         = "innodb_buffer_pool_size"
      value        = "{DBInstanceClassMemory*3/4}"
      apply_method = "pending-reboot"
    },
  ]

  tags = {
    Environment = "production"
  }
}
```

Then reference the output in a DB instance:

```hcl theme={null}
module "db" {
  source  = "terraform-aws-modules/rds/aws"
  version = "~> 7.0"

  identifier                = "mydb"
  create_db_parameter_group = false
  parameter_group_name      = module.db_parameter_group.db_parameter_group_id

  # ... other variables
}
```

## Input variables

<ParamField path="create" type="bool">
  Whether to create the parameter group resource.

  Default: `true`
</ParamField>

<ParamField path="name" type="string">
  The name of the DB parameter group. When `use_name_prefix` is `true`, this is used as a prefix.

  Default: `""`
</ParamField>

<ParamField path="use_name_prefix" type="bool">
  Determines whether to use `name` as-is or create a unique name beginning with `name` as the prefix.

  Default: `true`
</ParamField>

<ParamField path="description" type="string">
  The description of the DB parameter group.

  Default: `null`
</ParamField>

<ParamField path="family" type="string">
  The engine family for the parameter group (e.g. `mysql8.0`, `postgres15`, `oracle-se2-19`). This must match the engine version of the DB instance.

  Default: `null`
</ParamField>

<ParamField path="parameters" type="list(object)">
  A list of DB parameters to apply to the parameter group.

  Default: `null`

  <Expandable title="Object schema">
    <ParamField path="name" type="string" required>
      The name of the DB parameter (e.g. `max_connections`).
    </ParamField>

    <ParamField path="value" type="string" required>
      The value of the parameter. May use engine formula expressions such as `{DBInstanceClassMemory*3/4}`.
    </ParamField>

    <ParamField path="apply_method" type="string">
      When to apply the parameter. Valid values: `immediate`, `pending-reboot`. Defaults to `immediate`.
    </ParamField>
  </Expandable>
</ParamField>

<ParamField path="skip_destroy" type="bool">
  Set to `true` to prevent the parameter group from being deleted at destroy time. The resource is instead just removed from Terraform state.

  Default: `null`
</ParamField>

<ParamField path="region" type="string">
  Region where the parameter group will be managed. Defaults to the region set in the provider configuration.

  Default: `null`
</ParamField>

<ParamField path="tags" type="map(string)">
  A mapping of tags to assign to the DB parameter group resource.

  Default: `{}`
</ParamField>

## Outputs

<ResponseField name="db_parameter_group_id" type="string">
  The name (ID) of the DB parameter group. Pass this to the `parameter_group_name` input of a DB instance.
</ResponseField>

<ResponseField name="db_parameter_group_arn" type="string">
  The ARN of the DB parameter group.
</ResponseField>