In a prior blog we provided some tips on Managing HANA memory. In this article we will further explore the improvement with ESS (Embedded Statistics Service) available on HANA from SPS 7 revision 74 or higher. As a quick recap, memory consumption by the hdbstatisticsserver can be heavily impacted by the volume and frequency of various statistics collected by the HANA statistics engine, mainly the columnar tables in _SYS_STATISTICS schema. These tables provide stats for monitoring by tools such as the HANA Studio, SAP DBA Cockpit and Solution Manager, as well as external SAP management tools like IT-Conductor and HANA Management Pack for SCOM.
We've had the opportunity to work with HANA both as a Startup porting our application to HANA as well as with our SAP customers running HANA in production scale BW or ECC environments. In the R&D environment we have limited hardware capacity and thus resources, especially memory is always a constraint, so we learnt ways to monitor, and automate to optimize our performance and use of the system. In the customers' production environment, we have seen original architecture plans double in nodes and/or memory before they even got to performance testing phase.