Ans: HANA supports both type of data store in database. Row store is used when you need to use Select statement and no aggregations are performed.
Column store is used to perform aggregations and HANA Modeling is supported only on Column based tables.
2. Which companies are providing SAP HANA hardware appliances?
Ans: There are total 11 vendors for SAP HANA hardware appliances. Most common are −
- Dell
- IBM
- HP
- Cisco
- Lenovo
3. What is the use of SAP HANA studio?
Ans: HANA studio is an eclipsed based tool and provides support for development and administration in HANA system. You can perform HANA Modeling on the top of tables in database, Data provisioning, HANA Administration and various other activities using HANA studio.
SAP HANA Studio client is available for Windows XP, Windows Vista, and Windows 7 for 32 bit and 64 bit operating system.
4. What do you understand by SAP HANA In-Memory Computing Engine IMCE?
Ans: In-Memory concept of SAP HANA means that all the data is stored in RAM memory. A conventional database transfer data from memory in 5 milliseconds however SAP HANA In-memory takes 5 nanoseconds to read data.
SAP HANA uses multicore CPU architecture and stores data in row and column based storage in HANA database.
5. Which operating system is supported by HANA system?
Ans: Only operating system that is supported by HANA is Suse Linux Enterprise Server SP1/SP2 (SLES SP1/2).
6. What is the functional difference between Row and Column based storage? Where do we use Row based storage and column based storage?
Ans: Consider below table- FCTSales
| Country | Product | Units Sold |
| England | iphone 6 | 107 |
| India | Samsung Note 6 | 250 |
| US | Lenovo A110 | 110 |
Row Based Storage −
- England
- Iphone6
- 107
- India
- Samsung Note 6
- 250
- US
- Lenovo A110
- 110
Column Based Storage −
- England
- India
- US
- Iphone6
- Samsung Note6
- Lenovo A110
- 107
- 250
- 110
Where to use Row based storage?
Select * from FCTSales where Country=’US’
Where to use Column based storage?
Select SUM(Units_sold) from FCTSales where Product=’Lenovo A110’
7. What are the different components in SAP HANA Architecture? What is the use of Index server?
Ans:
- Index Server
- Name Server
- Statistical Server
- Preprocessor Server
- XS Engine
- SAP Host Agent
- LM structure
- SAP Solution Manager Diagnostic Agent
Index server contains engine to process data in HANA database. These data engines are responsible to handle all SQL/MDX statement in HANA system. Index server also contains Session and Transaction Manager which is responsible to manage all running and completed transactions.
8. What is the use of Persistence layer in SAP HANA system?
Ans: Persistence layer provides inbuilt mechanism for disaster recovery in HANA system. It ensures that database is restored to most recent state in case of a system failure.
Persistence layer also manages data, transaction and configuration logs and backup of these files. Backups of data and log files are performed at save points and is normally scheduled every 5-10 minutes.
9. What are the different license keys type in HANA system? What is their validity?
Ans:
- Temporary License key
- Permanent License Key
Temporary License keys are automatically installed when you install the HANA database. These keys are valid only for 90 days and you should request permanent license keys from SAP market place before expiry of this 90 days period after installation.
Permanent License keys are valid till the predefine expiration date. License keys specify amount of memory licensed to target HANA installation.
10. What are the different types of permanent license keys in HANA system?
Ans: There are two types of permanent License keys for HANA system −
Unenforced − If unenforced license key is installed and consumption of HANA system exceeds the license amount of memory, operation of SAP HANA is not affected in this case.
Enforced − If Enforced license key is installed and consumption of HANA system exceeds the license amount of memory, HANA system gets locked. If this situation occurs, HANA system has to be restarted or a new license key should be requested and installed.
11. While activating SAP HANA Modeling view, you get an error message −
Repository: Encountered an error in repository runtime extension; Deploy Attribute View: SQL: transaction rolled back by an internal error: insufficient privilege: Not authorized
Ans: Grant SELECT privileges on schemas of the used data foundation tables to user "_SYS_REPO"
GRANT SELECT ON SCHEMA "<SCHEMA_NAME>" TO _SYS_REPO WITH GRANT OPTION
12. In SAP HANA Studio, what is use of different folders when you add a HANA system to Studio?
Ans:
Backup −
It is used to perform for backup and recovery in SAP HANA system. You can check backup configuration details, run manual backup, to check last successful back performed, etc. for data and log backup.
Catalog −
This contains RDBMS objects like schemas, tables, views, procedures, etc. You can open SQL editor and design database objects
Content −
This is used to maintain design time repository
You can create new packages and design Information views in HANA system. Various views can be created under content tab to meet business requirement and to perform analytical reports on the top of the Modeling views.
Provisioning −
This is used for Smart data access to connect to other databases like HADOOP, TERADATA and SYBASE
Security −
This is used to define users and to assign roles. You can define various privileges on different users using Security tab. You can assign Database and Package privileges to different users to control the data access.
13. What is the difference between Open Data Preview and Open Definition?
Ans: Open Data Preview −
This is used to see the data stored in an object- table or a modeling view. When you open data preview, you get three options −
- Raw Data
- Distinct Values
- Analysis
Open Definition −
This is used to see the structure of the table − column name, column data type, keys, etc.
14. If you want to see all active alerts, description and priority, where this can be checked?
Ans: Go to Administration → alerts
In Administration tab, you can check system overview, landscape, volumes, configuration, system information, etc.
15. What is SAP HANA cockpit?
Ans: SAP HANA cockpit is a SAP Fiori Launchpad site that allows you with a single point-of-access to a range of Web-based applications for the online administration of SAP HANA. You access the SAP HANA cockpit through a Web browser.
To open SAP HANA Cockpit → Right click on HANA system in Studio → configuration and monitoring → open SAP HANA cockpit
16. What is the difference between Catalog and Content tab?
Ans:
Catalog −
This contains RDBMS objects like schemas, tables, views, procedures, etc. You can open SQL editor and design database objects.
Content −
This is used to maintain design time repository. You can create new packages and design Information views in HANA system. Various views can be created under content tab to meet business requirement and to perform analytical reports on the top of the Modeling views.
17. Which Information view in SAP HANA is used to implement star schema queries?
Ans: Analytic View
18. What is difference between Copy and derived from option while creating a new SAP HANA Attribute information view?
Ans: Copy option allows you to copy an existing Information view and to make changes to it.
Derived option allows to create a copy of an existing view and you can’t make any changes to it.
19. What is the use of Data Foundation, Star Join and Semantics?
Ans:
Data Foundation − to add column base tables.
Star Join − to add other type of views.
Semantic − to define user parameters and to define measures and dimensions.
20. What are the different user parameters that can be defined in Semantic layer?
Ans:
- Measure and Attribute
- Hierarchies
- Parameters/Variables
- New Calculated Column
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