ERROR: there are still “xyz” tasks not in state READY (RUN_RRC_READYFINAL)

In phase MAIN_DTTRANS/SUBMOD_RRC_STOP/RUN_RRC_READYFINAL, below error prompted,

====MARK ANALYZED SECTION==== END OF RUN_RRC_READYFINAL ====== BEGIN OF RUN_RRC_READYFINAL ========
-------------------------------------------------------------------------
Report name ...: "RSUPG_RRC_CRR"
Log name: "U:\SUM\abap\tmp\RRC_READYFINAL.SID"
Start time.....: "24.04.2021" "10:01:13"
-------------------------------------------------------------------------
All WP's on Server:

WP: "Nr20 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr21 , ReportSAPLSDEB, Client000, UserDDIC, Status""On Hold"" "" "
WP: "Nr22 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr23 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr24 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr25 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr26 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr27 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr28 , Report, Client, User, StatusWaiting"" "" "" "
WP: "Nr29 , Report, Client, User, StatusWaiting"" "" "" "
Using "13" of "16" free batch processes
Control Report RSUPG_RRC_CRR started with action "READYFINAL" at "10:01:13" ("24.04.2021")
ERROR: there are still "6.591" tasks not in state READY
END OF SECTION BEING ANALYZED END OF RUN_RRC_READYFINAL ==========================

Solution

Taken from SAP Note 1678564 – Restrictions, Database-specific Settings, and Troubleshooting of nZDM for SUM,

The first 12 steps are always the same, no matter if you are still in uptime or already in downtime (passing phase DOWNCONF_DT_TRANS). Then additional steps, depending on uptime/downtime, are needed.

For uptime and downtime:

1. Log on with DDIC to the shadow(!) system.
2. Start transaction SM50; notice the replication jobs.
3. In a second window, start transaction SE37.
4. Enter function module CRR_TRANSFER_CONTROL.
5. Execute (F8) the function module as test with parameter IV_ACTION = STOP.
6. Check the other window (SM50) and wait until all replication jobs are stopped. This should only take a few seconds at most.
7. Return to the SE37 window; the process will still be running (up to 20 minutes), but the wait is not needed: cancel the process (Menu symbol -> Stop Transaction).
8. Start SE37 again, and enter function module CRR_TRANSFER_CONTROL again.
9. Execute the function module as test with parameter IV_ACTION = START and IV_REQUESTED_BATCHES =[number of uptime replication processes].
10. Observe SM50; within a few seconds the replication jobs should return. There should also be a new process called RSUPG_ASYN_RUN_REPLICATE (the previously aborted job, now restarted)
11. Start transaction AL11, and navigate to the SUM/abap/tmp directory
12. Check that file RRC_REPLICATE.SID has been updated at the restart of the replication

For uptime only, after completing previous steps 1 to 12:

1. Go to the CRR Control Center of the SUM Utilities and start the replication
2. Check using transaction AL11 that file CRR_TRANSFER_CONTROL_STATUS. is updated again about every 15 seconds

For downtime only, after completing previous steps 1 to 12:

1. Switch to the window with SE37 and function module CRR_TRANSFER_CONTROL.
2. Execute (F8) the function module as test with parameter IV_ACTION = STOP, wait until the process finishes.
3. Resume SUM; if the phase RUN_RRC_READYFINAL passes, the issue is solved.