Snippet Name: RDS_PostgreSQL_Connection_Limits

Tags:

Created Date: 2025-06-16 13:12:44
Last Modified Date: 2025-05-31 10:32:06

Dependencies:

DBA Notes:

Sample Output:

Title: RDS PostgreSQL Connection Limits
Author: user
In AWS RDS Postgres instance, are there any default parameter changes that are recommended that are not default? specifically looking for possible limits and controls on:
o	User connections and session limits
o	Idle connection timeouts
o	Query execution time restrictions
o	Maximum number of concurrent queries per user

Author: ChatGPT
???To optimize your AWS RDS PostgreSQL instance for user connections, session management, and query execution, consider adjusting the following parameters:??????

**1. User Connections and Session Limits**

- **`max_connections`**: ???This parameter sets the maximum number of concurrent connections to the database. The default value varies based on the instance class. To view the current setting, execute:??????

  ???
```sql
  SELECT name, setting FROM pg_settings WHERE name = 'max_connections';
  ```
??????

  ???Adjust this value in your custom DB parameter group to align with your application's requirements and the instance's capacity.??????

**2. Idle Connection Timeouts**

- **`idle_in_transaction_session_timeout`**: ???Terminates any session that has been idle within an open transaction for longer than the specified time. The default is 0 (disabled). Setting this helps prevent long-running idle transactions that can hold locks and lead to table bloat. For example, to set a 5-minute timeout:??????

  ???
```sql
  ALTER SYSTEM SET idle_in_transaction_session_timeout = '300000'; -- time in milliseconds
  ```
??????

  ???After setting, reload the configuration:??????

  ???
```sql
  SELECT pg_reload_conf();
  ```
??????

  ???For more details, refer to the PostgreSQL documentation.??? ???cite???turn0search4??????

- **`idle_session_timeout`**: ???Terminates sessions that are idle without an open transaction for longer than the specified time. The default is 0 (disabled). Configure this to free up resources from inactive sessions:??????

  ???
```sql
  ALTER SYSTEM SET idle_session_timeout = '300000'; -- time in milliseconds
  ```
??????

  ???Then, reload the configuration:??????

  ???
```sql
  SELECT pg_reload_conf();
  ```
??????

  ???For more information, consult the PostgreSQL documentation.??? ???cite???turn0search4??????

**3. Query Execution Time Restrictions**

- **`statement_timeout`**: ???Aborts any statement that runs longer than the specified time. The default is 0 (no timeout). Setting this prevents excessively long-running queries:??????

  ???
```sql
  ALTER SYSTEM SET statement_timeout = '60000'; -- time in milliseconds
  ```
??????

  ???After setting, reload the configuration:??????

  ???
```sql
  SELECT pg_reload_conf();
  ```
??????

  ???Detailed information is available in the PostgreSQL documentation.??? ???cite???turn0search4??????

**4. Maximum Number of Concurrent Queries per User**

???PostgreSQL does not have a built-in parameter to limit the number of concurrent queries per user directly. However, you can manage this by:??????

- **Connection Pooling**: ???Implement a connection pooler like PgBouncer to control and limit user connections effectively.??????

- **Resource Management**: ???Utilize the `pg_stat_activity` view to monitor active queries and implement application-level logic to restrict user activity as needed.??????

**Implementing Parameter Changes in AWS RDS**

???In AWS RDS, you cannot modify parameters in the default parameter group. To apply custom settings:??????

1. **Create a Custom Parameter Group**:

   Use the AWS Management Console or AWS CLI to create a new DB parameter group.

2. **Modify Parameters**:

   Set the desired parameter values in your custom parameter group.

3. **Associate with Your DB Instance**:

   Assign the custom parameter group to your RDS instance. Some parameter changes may require a reboot to take effect.

???For comprehensive guidance on working with parameter groups, refer to the AWS RDS User Guide.??? ???cite???turn0search0??????

???By configuring these parameters appropriately, you can enhance the performance, reliability, and resource utilization of your AWS RDS PostgreSQL instance.??????