SAP HANA Articles - Page 14 of 58

In SAP HANA system architecture, Name server is used to maintain topology of SAP HANA system. It details complete information about system landscape- all hosts in distributed environment, active components and services running on each component in a distributed system environment.Topology details of SAP HANA system is maintained.Name server holds the detail of each component and services running on each host and hence reduces the re-indexing time.

It consists of various components as mentioned above for processing of SQL statements from application users hosted on the top of HANA system.User requests via user interface/web browsers are sent to Web server hosting application which is communicated to SQL/MDX Processor in form of SQL queries. These are further segregated to different data engines in Index server according to query types.Session and Transaction Manager authorize SQL transactions and keep track of all the transactions either completed or running in the system.

In SAP HANA system, Session and Transaction Manager is responsible to keep track of all the executed transactions in HANA database. It includes both running transactions and closed transaction. When a transaction in HANA system is failed due to any reason, Transaction Manager informs corresponding engine to handle the error.Session Manager is responsible to manage open and closed sessions and to authorize all the transactions executed in HANA db.

It will use both OLAP and Join engine. The join between the FACT and DIM will be executed in the OLAP engine and joins inside the attribute views will be executed in the JOIN engine so both the engines will be used.

Index Server is heart of SAP HANA system and is responsible for processing all SQL statements sent to HANA database. This server contains SQL/MDX Processing engine that is responsible to process and analyze data in HANA db.Index Server also contains Persistence layer for scalability and restoration of the system. In case of system failure, power failure or database corruption, Persistence layer is responsible for the restoration of HANA system to last save point.When you are running complex and large calculations, and there is a system failure Persistence layer is used to ensure that transactions are either fully executed or complete ... Read More

Each HANA system contains multiple serves inside, which are responsible to perform different functions. Index Server is heart of SAP HANA system which contains SQL/MDX processor for handling SQL statements. Key component includes −Index ServerPreprocessorName ServerStatistics ServerHANA XS EngineSAP Host AgentSAP Solution Manager Diagnostic AgentSAP HANA Studio + RepositorySAP HANA Software Update Manager SUM

You can use following SQL statement for this −CREATE VIRTUAL TABLE ExampleCREATE VIRTUAL TABLE ABC.test_VT AT “ORCL_11G_WIN”.”NULL”.”OUTLN”.”Dept”;In this SQL statement, ABC.test_VT is Virtual table name“ORCL_11G_WIN”.”NULL”.”OUTLN”.”Dept”;- Remote location for creating Virtual table

When a remote source is added, you can see all the existing tables under that data source in HANA Studio. Next is to create virtual table mapping to data in the remote data sources in SAP HANA Studio. This can be done using GUI option.To add a table as a virtual table, you need to navigate to remote data source → Schema name → Table name → Right-click and Add as Virtual TableBelow shows how you can add a table as a Virtual Table using HANA Studio.

Note that while modifying or creating the property configuration file, only the property which is different from default value needs to be set. The mistake in property configuration file may result in incorrect action or result of data source.

When you create a new remote data source, SAP HANA Smart data access parse the respective property configuration file. With the use of config file- features, function mappings, data type mappings, and other properties will be linked together with the data source. This decides the communication between the SAP HANA and the data source.You can see part of the content of property_orcl.ini shown below −