SAP HANA NSE, a native SAP HANA feature, is a “warm” data solution that provides an improved cost-to-performance ratio. It is comparable to other SAP HANA warm data-tiering solutions such as SAP HANA Extensions Node and SAP HANA Dynamic Tiering. Mission-critical (or “hot”) data is stored in memory on the SAP HANA database for real-time processing and analytics. Less frequently accessed (or “warm”) data is saved on disk, although it is still managed as a unified part of the SAP HANA database. Managing and retaining older data in this cost-effective way helps maintain data growth while minimizing the expense of hardware growth.
The following figure shows the difference between standard SAP HANA in-memory storage and the storage offered with NSE:
Figure 4. Comparison of standard SAP HANA database and SAP HANA database with NSE
The capacity of a standard SAP HANA database is limited by the amount of main memory. Using SAP HANA NSE, you can bypass these limits by storing warm data on disk storage. Paging operations require a relatively small amount of SAP HANA memory for the NSE buffer cache because the buffer cache can handle up to eight times the size of warm data on disk. For example, a 2 TB SAP HANA system without NSE equates to a 1 TB database in memory. With NSE and the addition of a 500 GB buffer cache, you can expand your 1 TB database to a 5 TB database consisting of 1 TB of hot data, 4 TB of warm data, and a 500 GB buffer cache to page data between memory and disk.
While hot data is “column loadable,” residing completely in-memory for fast processing and loaded from disk into SAP HANA memory in columns, with SAP HANA NSE you can specify certain warm data as “page loadable.” This page-loadable data is loaded into memory page by page as required for query processing. Unlike column-loadable data, page-loadable data does not have to reside completely in memory.
The following figure depicts the SAP HANA database with NSE:
Figure 5. SAP HANA database with NSE
NSE reduces the memory footprint for page-loadable data. The database is partly in memory and partly on disk, as illustrated in Figure 5. You can use the PowerMax storage array, together with SAP HANA NSE, to substantially increase SAP HANA data capacity and reduce TCO.
NSE is integrated with other SAP HANA functional layers, such as the query optimizer, query execution engine, column store, and persistence layers. For more information about the key features of NSE and related topics, see SAP HANA Native Storage Extension.
NSE is subject to certain functional restrictions. For more information, see SAP Note 2771956: SAP HANA NSE Functional Restrictions (access requires an SAP username and password).