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SAP HANA Interview Questions & Answers

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SAP HANA Interview Questions

1. Mention what is SAP HANA?

Answer: SAP HANA stands for High Performance Analytical Appliance- in-memory computing engine. HANA is linked to ERP systems; Frontend modeling studio can be used for replication server management and load control.

2. What is the development language used by SAP HANA?

Answer: C++

3. Name the operating system SAP HANA supports.

Answer: More than 70% of customers run their SAP workloads on Linux with the use of SUSE Linux Enterprise Server, which is the best OS choice for SAP HANA.

4. Does HANA/IMDB replace Oracle?

Answer: Once the Business Suite keeps running on IMDB, Oracle won’t be required any more by SAP clients who purchase HANA. This doesn’t affect anything in the short term because those people buying HANA today will still need an Oracle ERP system.

5. Mention the two types of Relational Data stored in HANA?

Answer: The two types of relational data stored in HANA includes

  1. Row Store
  2. Column Store

6. Explain Parallel Processing in SAP HANA?

Answer: Using the columnar data storage approach, the workload in SAP HANA is divided vertically. The columnar approach allows linear searching and aggregation of data rather than two-dimensional data structure. If more than one column is to be processed, each task is assigned to diverse processor. Operations on one column are then collimated by column divisions processed by different processors.

Go through this SAP HANA Tutorial to get a clear understanding of how SAP HANA works.

7. Can I just increase the memory of my traditional Oracle database to 2TB and get similar performance?

Answer: NO. You might have performance gains due to more memory available for your current Oracle/Microsoft/Teradata database but HANA is not just a database with bigger RAM.
It is a combination of a lot of hardware and software technologies. The way data is stored and processed by the In-Memory Computing Engine (IMCE) is the true differentiator. Having that data available in RAM is just the icing on the cake.

8. What does HANA cost?

Answer: SAP hasn’t completely affirmed HANA permitting costs yet the equipment is some place around $1-200k for every TB. Add to this permitting costs which are as yet being made on a for every client premise.

9. Mention what is the role of the persistence layer in SAP HANA?

Answer: SAP HANA has an in-memory computing engine and access the data straightaway without any backup. To avoid the risk of losing data in case of hardware failure or power cutoff, persistence layer comes as a savior and stores all the data in the hard drive which is not volatile.

10. What are the different license keys type in HANA system? What is their validity?

Answer:

  • 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.

11. If I can run NetWeaver BW on IMDB/HANA, why can’t I run the Business Suite/ERP 6.0?

Answer: Just on the grounds that it’s not develop enough yet to bolster business basic applications. From an innovation viewpoint, it is as of now conceivable to maintain the Business Suite on IMDB and SAP has trialed moving some vast databases into IMDB as of now.

12. What is SAP HANA cockpit?

Answer: 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

13. What is a new calculated column in a HANA Modeling view?

Answer: New calculated column is defined as a column added on the fly in Analysis tab when a view is activated. This column doesn’t exist at database level or in Data Foundation or Star Join level.

14. Why materialized aggregates are not required in HANA?

Answer: Since the SAP HANA database resides entirely in-memory all the time, additional complex calculations, functions and data-intensive operations can happen on the data directly in the database. Hence materialized aggregations are not required.

It also provides benefits like

      • Simplified data model
      • Higher level of concurrency
      • Simplified application logic

15. Mention what are the different compression techniques?

Answer: There are three different compression techniques

  • Run-length encoding
  • Cluster encoding
  • Dictionary encoding

16. List the merits and demerits of using row-based tables.

Answer:

Merits:

  • No data approach can be faster than row-based if you want to analyze, process and retrieve one record at one time.
  • This data storage and processing approach is easier and effective without any aggregations and fast searching.
  • It is preferred when the table consists of less number of rows.
  • Row-based tables are useful when there is specific demand of accessing complete record.

Demerits:

  • The data retrieval and processing operations involve the complete row, even though all the information is not useful.

Go through this in-depth SAP HANA training and master the powerful columnar database now!

17. Mention what is latency?

Answer: Latency is referred to the length of time to replicate data from the source system to the target system.

18. List advantages of column-based tables.

Answer: Allows smoother parallel processing of data as the data in columns is stored vertically. Thus, to access data from multiple columns, every operation can be allocated to a separate processor core.

  • Efficient operations since most columns hold unique values and thus, high compression rate.
  • Only specific columns need to be approached for Select query and any column can be used for indexing.

19. How does SAP HANA support Massively Parallel Processing?

Answer: With availability of Multi-Core CPUs, higher CPU execution speeds can be achieved.
Also HANA Column-based storage makes it easy to execute operations in parallel using multiple processor cores.

In a column store data is already vertically partitioned. This means that operations on different columns can easily be processed in parallel. If multiple columns need to be searched or aggregated, each of these operations can be assigned to a different processor core.

In addition operations on one column can be parallelized by partitioning the column into multiple sections that can be processed by different processor cores. With the SAP HANA database, queries can be executed rapidly and in parallel.

20. What is the main SAP HANA database component?

Answer: Index Server consists of actual data engines for data processing including input SQL and MDX statements and performs authentic transactions.

21. List the different compression techniques in HANA?

Answer:

  • Run-length encoding
  • Cluster encoding
  • Dictionary encoding

22. What is ad hoc analysis?

Answer: In traditional data warehouses, such as SAP BW, a lot of pre-aggregation is done for quick results. That is the administrator (IT department) decides which information might be needed for analysis and prepares the result for the end users. This results in fast performance but the end user does not have flexibility.

The performance reduces dramatically if the user wants to do analysis on some data that is not already pre-aggregated. With SAP HANA and its speedy engine, no pre-aggregation is required. The user can perform any kind of operations in their reports and does not have to wait hours to get the data ready for analysis.

23. Which are the top five use cases in SAP HANA?

Answer: The top use cases of SAP HANA are:

  1. Real time financial planning
  2. Genome analysis
  3. Customer segmentation
  4. Detective HANA and
  5. Profitability analysis

24. How we can use Data provisioning in SAP HANA studio?

Answer: Go to SAP HANA Modeler Perspective → Data Provisioning.

SAP HANA FAQs  on Architecture:

25. What are the row-based and column based approach?

Answer:

Row based tables:

      • It is the traditional Relational Database approach
      • It store a table in a sequence of rows

Column based tables:

      • It store a table in a sequence of columns i.e. the entries of a column is stored in contiguous memory locations.
      • SAP HANA is particularly optimized for column-order storage.

SAP HANA supports both row-based and column-based approach.

26. What is the Operating system requirement for SAP HANA?

Answer: SUSE Linux enterprise Server

27. Does SAP HANA require indexes or aggregates?

Answer: Every column in SAP HANA is stored as an index, and therefore HANA has no need for separate primary indexes. Secondary indexes with multiple columns are possible and used for OLTP scenarios like the Business Suite. HANA will also self-generate helper indexes to ensure that multi-column joins are efficient.

28. How to Secure a sap hana user connexion?

Answer: A Sap hana database user is protected in the first place with a password. However, a password is very often required at the command line in order to connect and execute a batch or an SQL script. The user name and password are then visible to anyone. In order to avoid that situation, it is possible to create a special key in relation to a particular user. User name and password are then invisible via the use of that key.

29. How to get sap hana performance solutions?

Answer: Like any other database, sap hana could suffer from low performance at one stage. It is therefore important to have a monitoring strategy in place in order to catch any performance issues. Reasons for slow performance are known and advices are available.

30. How to troubleshoot sap hana?

Answer: Errors in sap hana can happened and would be coming from various areas such as SQL script execution, in Memory Data growth, change of configuration, disk, cpu and memory issues.

31. What is the Purpose of SUM and LM structures?

Answer: SUM allows automatic download and installation of SAP HAN versions and upgrades from SAP Marketplace. LM structure stores details on the current product version installed.

32. How to manage hana users step by step?

Answer: A user has to be assigned the necessary privileges in order to work with sap hana database. Predefined privileges are available and ready to be granted to specific users such as Operation-users, Monitoring-User, backup-user.

33. Is it possible to load and replicate data from one source system to multiple target database schemas of HANA system?

Answer: Yes. It is possible for up to 4.

34. What is Configuration and Monitoring Dashboard?

Answer: It is an application that runs on SLT replication server to specify configuration information (such as source system, target system, and relevant connections) so that data can be replicated. It can also use it to monitor the replication status (transaction LTR).
Status Yellow: It may occur due to triggers which are not yet created successfully.
Status Red: It may occur if master job is aborted (manually in transaction SM37).

35. What are Transformation rules?

Answer: A rule specified in the Advanced Replication settings transaction for source tables such that data is transformed during the replication process. Example you can specify rule to
Convert fields
Fill empty fields
Skip records

36. What happens when you set-up a new configuration?

Answer: The database connection is automatically created along with GUID and Mass transfer id (MT_ID).
A schema GUID ensures that configurations with the same schema name can be created. The Mass transfer ID is used in the naming of SLT jobs and the system can uniquely identify a schema.

37. What is the relation between the number of data transfer jobs in the configuration settings and the available BGD work processes? 

Answer: Each job occupies 1 BGD work processes in SLT replication server. For each configuration, the parameter Data Transfer Jobs restricts the maximum number of data load job for each mass transfer ID (MT_ID).

38. What happens if the replication is suspended for a long period of time or system outage of SLT or HANA system?

Answer: The size of the logging tables increases.

39. What is the best way to manage, operate, and monitor sap hana systems ?

Answer: Sap Hana is a young database with interesting features. First of all Sap Hana is a in-memory database. It is accessible for administration via various channels. Directly from the Server, It is not the most convenient method but you can use hdbsql to manage databases. With the web based interface Hana cockpit you can browse and manage sap hana environments. The Client Hana Studio is the most complete tool to administer Sap Hana but it has to be physically installed and therefore is dependent of the client hardware.

40. How to avoid unnecessary logging information from being stored?

Answer: Pause the replication by stopping the schema-related jobs.

Enroll for Live Instructor Led Online SAP HANA Training


 

1 Responses on SAP HANA Interview Questions & Answers"

  1. Aakash says:

    Thanks for such detailed answers .These SAP HANA questions and answers are really good

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