Tag: migration

Custom code adjustments for HANA database migration

If you convert ECC to S4HANA you need to execute custom code adjustments for both HANA database migration and for functional application changes. This can be read in this blog and this blog.

If you only want to migrate an existing database to HANA for a netweaver ABAP stack (either standalone or for SAP ECC), you will also need to adjust custom code.

Questions that will be answered in this blog are:

  • Which custom code ABAP changes to I need to perform mandatory for a HANA database migration?
  • Which custom code ABAP changes are highly recommended to perform for a HANA database migration?
  • Which other tools should I use to help to smoothen the HANA database migration?

Mandatory custom ABAP changes for HANA database migration

There are mandatory ABAP changes to be made for HANA database migration. The main ones are:

  • Native SQL statements
  • Use of Database hints
  • Search in pool and cluster tables
  • Use of ADBC interface
  • Search for problematic statements without ORDER BY

The first few will not appear too much and are relatively easy to fix.

The last one: the statements without ORDER BY needs some explanation. Some current custom code might work properly with the current database, since some database will present the data to the ABAP application server in a specific sorted way. When migration to HANA database the HANA database might present the same records to the ABAP application server, but in a different sorting or in a random order. This might lead to issues in further handling in custom code. The solution is to analyze the code and to add explicit sorting as per need of the custom program. To scan the usage in live system, see below chapter on SRTCM.

All these changes can be detected with the SCI variant FUNCTIONAL_DB:

Run this SCI variant via the ATC tool on your custom code:

Wait for the run to finish and go to the results. The best overview is when you click the Statistics View button:

Clicking on an item will drill down to the details.

Performance related coding changes for HANA database migration

The second set of custom code changes is from the performance side. For this set you need to run the ATC tool with SCI variant PERFORMANCE_DB:

The PERFORMANCE_DB variant has 2 main parts: mandatory fixes, good to fix.

The mandatory fix is the unsecure use of SELECT FOR ALL ENTRIES. If this is not properly checked, it might blow up the system:

What happens here? If in the current database the SELECT FOR ALL ENTRIES for whatever reason is not giving results this might be running fine. But on HANA the entire table is read in this case. To scan the usage in live system, see below chapter on SRTCM.

The other part is the performance best practices for HANA:

This ATC run can yield a very long working list:

Where to start? Since even the priority 1 and 2 can yield a very long list.

Use the SQLM and SWLT tools. These tools will help you to prioritize the ATC run result from the PERFORMANCE_DB variant. SQLM will take statistics data from production. You start with the heavy used programs. SWLT will combine the heavy use with the ATC run. The output is the heavy used program which can be improved.

SRTCM tool

The SRTCM tool is specifically designed to scan for 2 main issues: Empty table in FOR ALL ENTRIES clause and Missing ORDER BY or SORT after SELECT. The tool is run on a productive system and will list the actual usage in a productive system.

To switch on start transaction SRTCM and press the Activate Globally button.

Let the tool run, and later Display Results from either running system or snapshot:

Show results;

Clicking on the line will jump to the direct code point.

Note for Oracle as source database: 3209584 – RTM: RTM_PERIODIC_JOB canceled with runtime error SQL_CAUGHT_RABAX (ORACLE).

Functionality issues after HANA database migration

Functional issues after HANA database migration are rare. Some might occur on an ECC system if there are minor bugs or issues in the HANA database optimized routines.

Example OSS notes:

Custom code decommissioning

SAP solution manager offers a custom code decommissioning cockpit tool. This tool you can use to delete unused custom code. Unused code does not need to be migrated, which will save you effort.

SAP references

Content server migration of documents

If you have configured attachments of document info records to be stored in the content server, you still might have a lot of old document stored into the SAP database.

This blog will explain how to migrate these documents from the database to the content server.

Questions that will be answered are:

  • How to migrate documents from database to content server?
  • What are relevant background OSS notes?

Running the migration

The main OSS note is 389366 – Relocation of documents. This basically tells you to run program RSIRPIRL. The exact use is explained in OSS note 2459712 – How to use report RSIRPIRL.

To run start transaction SE38 and start program RSIRPIRL and fill out the required data:

Select a time frame that has little documents in a test environment first. Check how long it takes and that it ends correctly. After the relocation is done you get a list of technical ID’s migrated. When confident in a test environment, run in production environment, and monitor the storage of the content server (so it does not fill up to 100%).

New modification note for delayed deletion: 2991944 – Introducing the Delay mode in report RSIRPIRL.

Migration of GOS objects

The program RSIRPIRL does not have many selection criteria. You might also find out that the time to migrate takes too long. If you need to migrate GOS document (global object services attachments), you can use program RSGOS_RELOCATE_ATTA:

This program migrates the GOS documents specified per type and page. GOS documents are normally the bulk of the documents. This way you can migrate most of the documents before running the full run with RSIRPIRL. Full background of program RSGOS_RELOCATE_ATTA can be found in OSS note 2293171 – RSGOS_RELOCATE_ATTA: Relocating attachments from generic object services.

Copying content repository

If you want to copy content from a content repository to another (not re-locate), install the program Z_DOC_COPY from OSS note 2774469 – Program to copy SAP content repositories.

Relevant OSS notes

OSS notes: