Defer Contention Management during Rebuild

A contention exit managing a resource request queue can request that contention processing be quiesced until the structure has either completed rebuilding or the rebuild process has been stopped. If the structure is in the rebuild process (either the CEPLREBUILD or the CEPLREBUILDORIG bit will be set ON), the contention exit can set the IXLRCCONTEXITREBUILDDEFER return code to specify that XES should not invoke the contention exit again for this resource until rebuild processing has completed. Requests for the resource continue to be queued and will be handled when the rebuild process ends.

If rebuild is not in progress (neither CEPLREBUILD nor CEPLREBUILDORIG is ON) and the contention exit returns to XES with the IXLRCCONTEXITREBUILDDEFER return code, XES issues an abend dump and terminates the connection.

Whether the contention exit actually is restarted depends on whether the contention exit is processing on behalf of the original structure or the new structure, and on the outcome of the structure rebuild.

If the contention exit is processing on behalf of the new structure (CEPLREBUILD=ON), the contention exit will be restarted when rebuild processing is complete. That is, after the connector has responded to the rebuild cleanup event with IXLEERSP EVENT=REBLDCLEANUP.
If the contention exit is processing on behalf of the original structure (CEPLREBUILDORIG=ON), the contention exit will be restarted only if the rebuild processing is stopped. That is, after the connector has issued IXLEERSP EVENT=REBLDSTOP.

At the completion of rebuild processing that was deferred with the IXLRCCONTEXITREBUILDDEFER return code, the contention exit will be restarted with the CEPLRESTARTAFTERDEFER bit set ON to indicate that this is the initial invocation of the contention exit for this resource after its deferral for rebuild processing.

When the contention exit is restarted, the contents of the CEPL will be identical to its previous contents when the request to defer processing was specified. During the previous invocation of the contention exit, if updates to the CEPL work areas were made, those updates are preserved.

A connector who was reflected on the resource request queue of the previous invocation of the contention exit might no longer be represented on that queue. This situation could occur because the connector failed or disconnected. The CEPLRECOVERY flag is set ON to indicate that the failed or disconnected user has been removed, if cleanup has completed.