Understanding reasons for retained locks and locking duration

The following conditions delay the release of exclusive record locks for an indefinite period of time:

A sysplex failure
An MVS™ failure
A failure of an instance of the SMSVSAM server or DFSMStvs
The last close by all users of the data set on this system image
However, when the application that closed the data set reaches the sync point, this problem is resolved.
A commit or backout processing failure

When these conditions occur, the affected exclusive record locks are converted to retained locks. Any subsequent attempt to obtain a retained record lock fails immediately rather than waiting for the lock to be released.

A VSAM request obtains the record lock and the lock is held until released by DFSMStvs during commit or backout processing.

If an application uses sequential, skip-sequential, or direct NSP (note string position) requests to modify data sets that were accessed by DFSMStvs, ensure that your application writes the modified buffers to the coupling facility before issuing a commit or backout request.