Cross-Transaction Locks

Stopping Cross-System Locks

Simple cross-system locks always terminate implicitly when the SAP LUW of the application terminates that requested the CSL. A CSL can also be stopped for multiple LUWs. To do this, the application program in the LUW generates a reference to the cross-system lock (a reference to the token), which is then transferred to an application program in another LUW. The CSL recognizes at the end of the update that there are still references to the token and rejects all requests from other applications that do not have a reference.

A prerequisite for a cross-transaction lock is a lock request by the initial LUW (function module CSLEO_ENQUEUE) with PSCOPE=2 (standard lock duration until the update).

Using References

When a reference is assigned to a token, the CSL increases the counter for the token by one and sets the status of the token to REFD. The reference is assigned to the LUW of the application that requested the lock. The CSL recognizes from the counter at the end of the update that there are still references to the token. If the reference counter is larger than 0, the CSL remains.

To reset the counter, the assigned references have to be used. The application that created a reference must transfer it to another application (by RFC or as part of an IDoc message, for example). First, the application program has to transfer the reference to the CSL in the dependent LUW ( CSLEO_USEREF module). The reference then has authorization to lock the token using the CSLEO_ENQUEUE module. The dependent LUW can then request additional references, which it can transfer to other LUWs. The concept can be cascaded.