Program BTCTRNS2 is used to reschdule jobs, that were suspended by BTCTRNS1. But it also initializes the job repository. The job repository needs to run in order to handle the remaining part of the data conversion, the so-called Silent Data Migration (SDM).
Conversion of application data usually happens during release upgrades or updates during downtime. In contrast, the Silent Data Migration Infrastructure (SDMI) allows zero downtime upgrades and runs after the upgrade (or conversion) during business operations.
Note
Although it is called Silent Data Migration, this is not part of the migration - but of the conversion! So it should actually be Silent Data Conversion!An SDMI supports uptime capability for at least one release. Therefore, zero downtime upgrades are possible if every release is taken into account. If an upgrade jumps over a certain release (for example, if the upgrade goes from SAP S/4HANA 2021 straight to SAP S/4HANA 2023), the SDMIs from the release that was jumped over (in this example, SAP S/4HANA 2022) are done during business downtime (if they do not support uptime capability for the target release).
When the system comes out of the maintenance mode after the upgrade (or conversion), the SDMI job from the job repository starts and calls the SDMIs in each client individually. To see all relevant SDMIs, call transaction SDM_MON.
A user is therefore required in every client. The user can be maintained in transaction SDM_USER and can also be created during the SUM process, when a dialog box appears asking you whether technical users for SDMIs should be created. In this dialog, choose Yes, to allow the SUM to create the technical users. If you choose No, the SUM will not create the technical users in clients where they are missing. During the post-processing phase, the SUM checks if the technical user exists. If not, a message will be created in the update log. If the users are not created, the SDMIs cannot be started and the data will not be migrated. The SDMIs need to be done before the next upgrade can happen.
The technical user for SDMI requires user type SYSTEM and profile SAP_ALL. For more details, see SAP Note 2850918.
For more details, see SAP Notes 2664638, 2907976, and 2821421.