10 important SAP HANA interview questions

1. What is SAP HANA?

SAP HANA is an in-memory computing engine(IMCE) used for real –time processing of huge

volume of data and building and deploying real world applications. Adopting the row –based

and column based DB technology. SAP HANA is an anvanced relational DB product serviced by

SAP SE. With this high- performance analytic system, the big data exists on the main memory

and not on the hard disk.

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

C++ programming language.

3. Name the operating system SAP HANA supports?

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.Explain Parallel Processing in HANA supports ?

Using the columnar data storage approach, the work load 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.

5. Advantages of SAP HANA

• With the HANA technology, you can create gen-next applications giving effective and efficient

results in the digital economy.

• By using singe data-in memory, SAP HANA supports smooth transaction process and fault-

tolerant analytics

• Easy and simple operations using an open-source, unified platform in the cloud

• High-level Data Integration to access massive amounts of data

• Advanced tools for in-depth analysis of present, past and the future.

6. List the merits and demerits of using row based tables?

Merits:

• No data approach can be faster than row-based if you want to analyze, process and retrieve

one record at one time.

• Row-based tables are useful when there is specific demand of accessing complete record.

• It is preferred when the table consists of less number of rows.

• This data storage and processing approach is easier and effective without any aggregations

and fast searching.

Demerits:

• The data retrieval and processing operations involve the complete row, even though all the

information is not useful.

7. List advantages of column based tables ?

• 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.

• Only specific columns need to be approached for Select query and any column can be used

for indexing.

• Efficient operations since most columns hold unique values and thus, high compression rate.

8. What table type is preferred in SAP HANA Administration : column- =based or row-based

Since analytic applications require massive aggregations and agile data processing, column-

based tables are preferred in SAP HANA as the data in column is stored consequently, one after

the other enabling faster and easier readability and retrieval. Thus, columnar storage is

preferred on most OLAP (SQL) queries. On the contrary, row-based tables force users to read

and access all the information in a row, even though you require data from few and/or specific

columns.

9. What is the main SAP HANA database component?

Index Server consists of actual data engines for data processing including input SQL and MDX

statements and performs authentic transactions.

10. Explain the concept of Persistence Layer?

The persistence layer in SAP HANA handles all logging operations and transactions for secured

backup and data restoring. This layer manages data stored in both rows and columns and

provides steady savepoints. Built on the concept of persistence layer of SAP’s relational

database, it ensures successful data restores.

Besides managing log data on the disk, HANA’s persistence layer allows read and write data

operations via all storage interfaces.

Author : Noushad Kabeer

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