Visual Composer does not close RFC sessions in the backend

[mark_moshkovich]

While running VC applications, any connection opened from the NetWeaver portal remains open until the application closes it: when you close the browser or when the HTTP session expires. However, this does not mean that the session in the back end has been released at that time.

Closing the connection does not terminate the session. What really occurs is that the connection is returned to a connection pool as a free connection. If, during the time that the connection is in the pool, another iView or application needs a connection with the same properties, the application will receive that connection from the free connections pool.

After the Connection Lifetime timeout, the connection is no longer valid, the cleanup thread destroys it and the session in the back end is released.

The cleanup thread actually checks each free connection in the pool and cleans out any connections that have timed out. For example, if the iView connects to BI or any R/3 back end, the connection in SM04 will be removed from the display only after the cleanup thread has cleaned up all connections for which their Connection Lifetime has expired.

You can optimize the connection pool settings in order to make the connection pooling mechanism more effective. To do so, use the following settings:

• Max connection set in the Admin tool too low
  The maximum number of connections allowed in the connection pool has been reached. Check the connector properties in the Visual Administrator for an explanation of the values:
• Expiration
  When enables, this option lets you configure the Connection Lifetime and the cleanup interval (more details following)
• Connection Lifetime
  Defines how long a connection may be retained in the connection pool. Once the period specified (in seconds) expires, the connection is removed from the pool and is replaced by a newer one. To maintain a connection indefinitely (never expiring), specify 0.
• Cleanup Thread
  Defines how often the system runs a thread, to destroy all unused connections. To prevent the thread from ever running (no cleanup), enter 0.
• Maximum Connections
  Specifies to the underlying EIS the maximum number of connections that can be stored in the connection pool. Default is 100.
• Maximum Time to Wait for Connection
  Used if the connection pool does not hold a connection that satisfies the client request; that is, the parameters of the available connections differ from those required. This property defines the time (in seconds) that the system must wait before creating a new connection when no suitable connection is available. Default is 60.
• JCO limit too low
  Defined in environment variable CPIC_MAX_CONV. Check attached SAP Note 314530.
• Backend limit too low
  The back end may limit the number of concurrent users or maximum number of sessions allowed for a single user. You can use SM04 to see how many sessions are currently open for each user. To set the maximum values for concurrent users and sessions, you must contact your BI / CRM / ERP system administrator.

By adjusting these settings, you should be able to solve the problem.