What is SAP HANA
SAP HANA is a database but it’s more than ordinary database, it’s an next generation data analytic appliance. At the software layer some components of SAP HANA act as database but the numerous act the next generation feature such as geospatial engine, predictive analytics engine, OLTP and full-text or fuzzy text search engine.
SAP HANA Software Layers
SAP HANA as database incorporate columnar table because columnar table is suitable for processing of analytic queries and have two advantages, the first advantage is their ability to facilitate analytic queries. Because these type of queries actually use grouping, ranking, aggregating and sort so the columnar tables are perfect to facilitate this analytic queries because columnar tables provide better mechanism for large data. The second advantage is better for compressing the data.
SAP HANA in-memory database layer contains multiple query processing engines such as calculation engine, OLAP engine, row engine, and join engine. this layer also contains the row tables and columnar table, engine to manages full-text search and fuzzy text search. and others important engine HANA XS ( Extended Application Service ) Engine, Predictive Analytics, Business Function Libraries, planning engines, rule engines, and geospatial engine.
SAP HANA Hardware and Layers
SAP HANA is in-memory database, the data is stored in dynamic random access memory ( DRAM ) and within CPU cache because of those the software enable to deliver fastest performance for huge data because data is stored close to the CPU. Not like traditional database store and access data on disk drive make slower in accessing data.
But hardware limitation in one server for CPU numbers and RAM capacity is limited. even though modern server can accomodate 8-12 TB of RAM. However SAP HANA have ability that allow use memory and CPU horsepower from multiple servers.
You can watch this video Why we must use SAP HANA today to accomodate huge data volume.