SAP HANA Architecture
Data is pack together by different compression techniques in SAP HANA Architecture. For example cluster encoding, run length encoding, sparse encoding, dictionary encoding and also indirect encoding.
When main memory maximum is reach in SAP HANA, the whole database objects for instance table, view etc. However those are not it use will be unload from the main memory and save into the disk.
Therefore these objects names are defined by application semantic and reload into main memory from the disk when require again. Under normal circumstances SAP HANA database manages unloading and loading of data automatically.
However, the user can load and unload data from individual table manually. Subsequently by selecting a table in SAP HANA studio in respective Schema- by right-clicking and selecting the option “Unload/Load”.
SAP HANA Server consists
- Index Server
- Preprocessor Server
- Name Server
- Statistics Server
- XS Engine
SAP HANA Index Server
SAP HANA Database Main servers are index server. Detail of each server is as below
Firstly it’s the main SAP HANA database component.
Secondly it contains actual data stores and the engine for processing the data.
Index Server processes incoming SQL or MDX statement.
Session and Transaction Manager
Session Component manages sessions and connections for SAP HANA database. Transaction Manager coordinates and control transactions.
SQL and MDX Processor
SQL Processor component queries data and send to them in query processing engine i.e. SQL/SQL Script / R / Calc Engine. MDX Processor queries and manipulates Multidimensional data. For example Analytic View in SAP HANA.
SQL / SQL Script / R / Calc Engine
This Component executes SQL / SQL script and calculation data convert in calculation model.
Repository maintains the versioning of SAP HANA metadata object For instance Attribute view, Analytic View, Store procedure.
During this layer uses in-built feature “Disaster Recovery” of SAP HANA database. Similarly backup is save in it as save points in the data volume.
Meanwhile this server is use in Text Analysis and extracts data from a text when the search function is use.
Moreover this Server contains all information about the system landscape. In distribute server, the name server contains information about each running component and location of data on the server. This server contains information about the server on which data exists.
Statistic server is responsible for collecting the data relate to status, resource allocation / consumption and performance of SAP HANA system.
XS Server contains XS Engine. It allows external application and developers to use SAP HANA database via the XS Engine client. The external client application can use HTTP to transmit data via XS engine for HTTP server.