Updating SAP ABAP Systems on UNIX and Linux: SAP HANA DB

Using the Record & Replay Technique in nZDM

With the introduction of the Record & Replay technique in nZDM, which uses the Change Recording and Replication (CRR) framework, you can now capture database changes in tables on the production instance during uptime.

Context

This trigger-based change recording technique allows importing new content into the shadow instance and adjusting table structures to the new release while all users are still able to work in the production system. The Software Update Manager starts the recording of data changes automatically and transfers it to the shadow instance iteratively after the table structure adjustment.

To control the change recording, you can perform the following actions:

Procedure

  • Control the Data Transfer (Monitoring, Stop, and Restart)

    Use the CRR Control Center to monitor, stop, and restart the data transfer. You find it in the SUM Utilities (Extended UI) and there as part of the Process Control Center.

  • Include or Exclude Tables into or from the Data Transfer

    Proceed as follows:

    1. From the subdirectory <SUM directory>/abap/control open the template file CRRTABLIST.LST.

    2. Add an entry to the existing entries in the CRRTABLIST.LST file using the following format:

      • To include a single table: I <Tabname>

      • To exclude a single table: E <Tabname>

  • Include Large Tables

    The Software Update Manager checks whether a table is larger than 50 Gigabytes. Such large tables are excluded by default from the data transfer.

    However, you have the option to include them as described previously.

  • Stop the Shadow Instance During the Data Transfer
    You can perform this action, for example, when you make an offline backup.

    1. Stop the data transfer in the CRR Control Center.

    2. In the command-line tool, enter the following command:

      <SUM directory>/abap/bin/SAPup stopshd

  • Start the Shadow Instance

    1. In the command-line tool, enter the following command:

      <SUM directory>/abap/bin/SAPup startshd

    2. Restart the Data Transfer in the CRR Control Center.