Data is compressed by different compression techniques (e.g. dictionary encoding, run length encoding, sparse encoding, cluster encoding, indirect encoding) in SAP HANA Column store.
When main memory limit is reached in SAP HANA, the whole database objects (table, view,etc.) that are not used will be unloaded from the main memory and saved into the disk.
These objects names are defined by application semantic and reloaded into main memory from the disk when required 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 by selecting a table in SAP HANA studio in respective Schema- by right-clicking and selecting the option "Unload/Load".
SAP HANA Server consists of :
When main memory limit is reached in SAP HANA, the whole database objects (table, view,etc.) that are not used will be unloaded from the main memory and saved into the disk.
These objects names are defined by application semantic and reloaded into main memory from the disk when required 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 by selecting a table in SAP HANA studio in respective Schema- by right-clicking and selecting the option "Unload/Load".
SAP HANA Server consists of :
- Index Server
- Preprocessor Server
- Name Server
- Statistics Server
- XS Engine
SAP HANA Index Server:
SAP HANA Database Main server are index server. Detail of each server is as below-
It's the main SAP HANA database component
It contains actual data stores and the engine for processing the data.
Index Server processes incoming SQL or MDX statement.
SAP HANA Index Server overview
Session and Transaction Manager: Session Component manage 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 (e,g. 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: Repository maintain the versioning of SAP HANA metadata object e.g.(Attribute view, Analytic View, Stored procedure).
Persistence layer: This layer uses in-built feature "Disaster Recovery" of SAP HANA database. Backup is saved in it as save points in the data volume.
Processor Server:
This server is used in Text Analysis and extracts data from a text when the search function is used.
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