How to clear a full SQL Server connection pool?

To clean up the SQL Server connection pool, you can follow these steps:

1. To confirm that the connection pool is full, you can monitor the performance counters of SQL Server, such as “User Connections,” to see the current usage of the connection pool. If the number of connections has reached or is close to the maximum limit, then the connection pool may be full.
2. You can check which connections are active in the connection pool by using the sys.dm_exec_connections dynamic management view.
3. To disconnect connections no longer needed, you can use the ALTER DATABASE statement to set them offline. For example, you can disconnect specific connections using the following command:
4. Set the database [database name] offline immediately with rollback.
5. Please note that this command will immediately rollback any unfinished transactions on the connection.
6. To increase the maximum number of connections in the connection pool: If the connection pool is often full, consider increasing the maximum number of connections in the pool. Use the following command to increase the maximum number of connections in the pool:
7. Change the maximum number of connections for the database named [database name] to [new maximum number of connections].
8. Note: Increasing the maximum number of connections may lead to an increase in server load, so it is important to balance and adjust based on actual needs.
9. Restart the SQL Server service: If the above steps are not effective, consider restarting the SQL Server service to clear the connection pool and release all connections.

Before performing any operation, it is important to backup the database and ensure a thorough understanding and appropriate permissions are in place.