Preprocessing

In this roadmap step, SUM creates the shadow system.

The shadow system is then used for various update activities while you can still use the original system in production operation. The SUM builds up the shadow system by cloning parts of the original system. All tables of the SAP NetWeaver Application Server are needed as shadow tables to operate the shadow system.

The shadow system is used to perform the modification adjustment of the ABAP Dictionary objects and the activation of new ABAP Dictionary objects that are part of the update. Finally, the Software Update Manager performs the shadow import and writes directly into the shadow tables.

Modifications to the contents of the original tables are indicated by triggers. These tables are copied and imported during downtime.

The following actions are carried out:

Checks for locked objects
ABAP Workbench locking

Note

In contrast to the standard upgrade procedure, the Software Update Manager offers during the release upgrade with DMO a second phase LOCKEU_PRE to lock the ABAP Workbench. Thus, you can lock it either in phase LOCKEU_PRE or in phase REPACHK2, in which you have to perform the step at the latest.
If you confirm the lock already in phase LOCKEU_PRE, the Software Update Manager does not stop in the REPACHK2 phase to allow you to confirm the lock on the ABAP Workbench. This increases the time in which the Software Update Manager does not need user input after the last request for a mount directory.
Furthermore, you may not perform any more transports into or out of the SAP system.
Running the shadow system for preparation of new release (ACT_UPG, PARDIST, SGEN)
(and subsequent to the following DMO-specific actions:) Transition to the downtime (system isolation)

DMO-specific actions:

Uptime migration: Repository
Execution of SMIGR_CREATE_DDL
Execution of phases related to SAP Business Warehouse

Further features:

In the phase MIG2NDDB_HANA_BW_PARAMS, provide parameters for SAP BW-specific cleanup tasks.
Temporary database space, which is required for the shadow system and is calculated during the execution of the roadmap step Checks, is too generous.

You can use the command <SUM directory>/abap/bin/SAPup dmpspc to check the used space at different points of time.
Phase REQ_PARTITIONING_MATDOC: After the completion of all EU_CLONE*CREATE phases, the Software Update Manager prompts you to provide a proper partitioning for table MATDOC, a new S/4HANA table for material documents. During database migration procedure, this table can reach or exceed the SAP HANA limit of 2 billion records for non-partitioned column-store tables depending on the posting volume of material documents. This makes a partitioning for large tables necessary.

For more information, see SAP Note 2259038 . If applicable, perform the corrections described in this SAP Note.