In the podcast “Debating the Value of SAP HANA” mentioned in my previous post, we ran into the discussion if SAP NetWeaver BW 7.3 SP5 powered by SAP HANA (project “BW Orange”, or simply “BW-on-HANA”) is the killer app or not for SAP in-memory technology. My answer was “Yes”, but here I would like to go into the grades of shade beyond this binary question.
There are very few customers out there, who would not complain about some aspects of the performance of SAP/BW. I had been presenting sessions on BW performance at different conferences since 2008, and they always resonated with the audience. BW-on-HANA, which comes with the major promise of performance boost for both front-end (querying/planning) and data warehousing parts, will resonate with almost every BW customer. I see it in my day job as a consultant.
It is a no-brainer that reading all data at the speed of RAM, instead of disks, will resolve lots of I/O-heavy processing. You may share my memories of frustration, waiting for long-running BW operations – queries, DTPs, extractions, where the only proof that the work session is still alive was to go to transaction DB02, find your running SQL and then see slowly but steadily increasing numbers under “blocks read”. This should be a song of the past with BW running with HANA system. The advantages of in-memory data retrieval are obvious, and there should be no discussion about this aspect of BW Orange.
But I/O bottleneck is not the only reason for slow performance. Accordingly to SAP’s own statistics presented during SAP TechEd’10 USA in ERP about 20% of the processing is happening in the database layer, and the rest 80% is in application (ABAP) layer. Obviously in this case super fast database can resolve only 20% of performance issues. Althought the ratio 20/80 will be different for BW, as more heavy BW joins or massive inserts are done, the problem remains the same. Through the years BW (like most of the other ABAP-based systems) was built to run lots of the intensive processing in the application layer. Analytics (OLAP and Planning) Engine) being the prominent example. DSO activations, SID calculations, user exits are some more examples from the data warehousing part of BW.
Therefore BW Orange release introducing some applications optimizations, which are specific to SAP HANA and cannot be reused by BW running on any other database system. You may have heard about those by now:
- HANA-optimized InfoCubes, i.e. different technical design of underlying database tables, and different querying technology,
- HANA-optimized DSOs and the new activation process executed in the db layer,
- New Planning Applications Kit, which allows execution of BW-IP standard functions within HANA db.
As you see the list of optimizations is not going through all BW components. Additionally, optimizations are not 100% applicable, i.e. in some cases tables layouts remain the same as on regular databases and processing is executed in ABAP layer, like in case when DSO is supplied by RDA real-time data acquisition (see OSS Note 1665322 – Conversion for SAP HANA-optimized DataStore objects). In some other cases “Remodeling might be required to leverage Hana optimization when starting from an existing scenarios” (OSS Note 1637199 – Using the planning applications KIT).
The human brain and hands are not yet completely eliminated, and we all are just at the beginning of the extremely interesting journey.