This method clears the connection pool that is associated with the provided OracleConnection object.


// C#
public static void ClearPool(OracleConnection connection);


When this method is invoked, all idle connections are closed and freed from the pool. Currently used connections are not discarded until they are returned to the pool.

Beginning with ODP.NET 12c Release 1 (12.1), ClearPool does not automatically repopulate the pool with new connections. This prevents the pool from being repopulated with invalid connections if client remains unable to connect with the database server. Developers programmatically control when the pool is repopulated by calling OracleConnection.Open(), which will repopulate the pool with at least the Min Pool Size number of connections.

Connections created after this method invocation are not cleared unless another invocation is made.

This method can be invoked with an OracleConnection object before opening the connection as well as after, provided the ConnectionString is properly set.


InvalidOperationException – Either the connection pool cannot be found or the provided connection string is invalid.


// C#
// Sample demonstrating the use of ClearPool API in OracleConnection class
using System;
using Oracle.DataAccess.Client;
class ClearPoolSample
  static void Main()
    Console.WriteLine("Running ClearPool sample..." );
    // Set the connection string
    string strConn = "User Id=scott;Password=tiger;Data Source=oracle;" +
                     "Min pool size=5;";
    OracleConnection conn = new OracleConnection(strConn);
    // Open the connection
    // Clears the connection pool associated with connection 'conn'
    OracleConnection.ClearPool (conn);
    // This connection will be placed back into the pool
    conn.Close ();
    // Open the connection again to create additional connections in the pool
    // Create a new connection object
    OracleConnection connNew = new OracleConnection(strConn);
    // Clears the pool associated with Connection 'connNew'
    // Since the same connection string is set for both the connections,
    // connNew and conn, they will be part of the same connection pool.
    // We need not do an Open() on the connection object before calling
    // ClearPool
    OracleConnection.ClearPool (connNew);
    // cleanup