SAP HANA Interview Questions And Answers

1).Mention what is SAP HANA?

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

Ans) The two types of relational data stored in HANA includes

  • Row Store
  • Column Store

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

Ans)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.


4).Mention what is modeling studio?

Ans)Modeling studio in HANA performs multiple task like

  • Declares which tables are stored in HANA, first part is to get the meta-data and then schedule data replication jobs
  • Manage Data Services to enter the data from SAP Business Warehouse and other systems
  • Manage ERP instances connection, the current release does not support connecting to several ERP instances
  • Use data services for the modeling
  • Do modeling in HANA itself
  • essential licenses for SAP BO data services

5).Mention what are the different compression techniques?

Ans)There are three different compression techniques

  • Run-length encoding
  • Cluster encoding
  • Dictionary encoding

6). Mention what is latency?

Ans)Latency is referred to the length of time to replicate data from the source system to the target system.


7). Explain what is transformation rules?

Transformation rule is the rule specified in the advanced replication setting transaction for the source table such that data is transformed during the replication process.


8).Mention what is the advantage of SLT replication?

Ans)SAP SLT works on trigger based approach; such approach has no measurable performance impact in the source system

It offers filtering capability and transformation

It enables real-time data replication, replicating only related data into HANA from non-SAP and SAP source systems

It is fully integrated with HANA studios

Replication from several source systems to one HANA system is allowed, also from one source system to multiple HANA systems is allowed.


9).Explain how you can avoid un-necessary information from being stored?

Ans)To avoid un-necessary information from being stored, you have to pause the replication by stopping the schema-related jobs


10).Mention what is the role of master controller job in SAP HANA?

Ans) The job is arranged on demand and is responsible for

  • Creating database triggers and logging table into the source system
  • Creating Synonyms
  • Writing new entries in admin tables in SLT server when a table is replicated/loaded

11).Explain what happens if the replication is suspended for a longer period of time or system outage of SLT or HANA system?

Ans) If the replication is suspended for a longer period of time, the size of the logging tables increases.


12).Mention what is the role of the transaction manager and session?

Ans)The transaction manager co-ordinates database transactions and keeps a record of running and closed transactions. When transaction is rolled back or committed, the transaction manager notifies the involved storage engines about the event so they can run necessary actions.


13).Explain how you can avoid un-necessary logging information from being stored?

You can avoid un-necessary logging information from being stored by pausing the replication by stopping the schema-related jobs.


14).Explain how SQL statement is processed?

Ans)In the HANA database, each SQL statement is implemented in the reference of the transaction. New session is allotted to a new transaction.


15). Name various components of SAP HANA?

Ans)SAP HANA DB

SAP HANA Studio

SAP HANA Appliance

SAP HANA Application Cloud


16).What is the development language used by SAP HANA?

Ans)C++


17).Name the operating system SAP HANA supports.

Ans) 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.

18). Explain Parallel Processing in SAP HANA?

Ans)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.


19).List advantages of using SAP HANA database.

Ans)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.


20). List the merits and demerits of using row-based tables?

Ans) 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.


    • 21).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.

    • 22).What table type is preferred in SAP HANA Administration: column-based or row-based?

    Ans)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.


    23).What is the main SAP HANA database component?

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


    24).Explain the concept of Persistence Layer?

    Ans)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.


    25).Define Modeling Studio in SAP Hana Administration?

    Ans)Modeling Studio is an operational tool in SAP HANA based on Eclipse development and administration, which includes live project creation.

    The SAP HANA Studio further builds development objects and deploys them, to access and modify data models like HTML and JavaScript files.

    It also handles various data services to perform data input from SAP warehouse and other related databases.

    Responsible for scheduling data replication tasks.


    26). List the different compression techniques in HANA?

    Ans)

    • Run-length encoding
    • Cluster encoding
    • Dictionary encoding

    27).Explain SLT?

    Ans)SLT expands to SAP Landscape Transformation referring to trigger –based replication. SLT replication permits data transfer from source to target, where the source can be SAP or non-SAP while the target system has to be SAP HANA with HANA database. Users can accomplish data replication from multiple sources. The three replication techniques supported by HANA are:

    • SLT
    • SAP Business Objects Data Services (BODS)
    • SAP HANA Direct Extractor Connection (DXC)

    28).Name the replication jobs in SAP HANA?

    Ans)Master Job (IUUC_MONITOR_)

    Data Load Job (DTL_MT_DATA_LOAD__)

    Master Controlling Job (IUCC_REPLIC_CNTR_)

    Migration Object Definition Job (IUCC_DEF_MIG_OBJ_)

    Access Plan Calculation Job (ACC_PLAN_CALC__)


    29).What is Latency?

    Ans) The time duration to perform data replication starting from the source to the target system is known as latency.


    30).What are the various components of SAP HANA Administration?

    Ans) SAP HANA Studio

    SAP HANA Application Cloud

    SAP HANA Cloud

    Sap HANA DB


    31).How to perform backup and recovery operations?

    Ans) During a regular operation, data is by default stored to the disk at savepoints in SAPHANA. As soon a there is any update and transaction, logs become active and get saved from the disk memory. In case of power failure, the database restarts like any other DB returning to the last savepoint log state. SAP HANA requires backup to protect against disk failure and reset DB to the previous state. The backups simultaneously as the users keep performing their tasks.


    32).Define SLT Configuration?

    Ans)Configuration is the meaningful information to establish a connection between source, SLT system and SAP HANA architecture as stated in the SLT system. Programmers are allowed to illustrate a new Configuration in Configuration and Monitoring Dashboard.


    33).What is Stall?

    Ans)The waiting process for data to load from the main memory to the CPU cache is called Stall.


    34).Define different types of information views?

    Ans)There are primarily three types of information views in SAP HANA, which are all non-materialized.

    • Attribute view
    • Analytic view
    • Calculation View

    35). What are Configuration and Monitoring dashboard?

    Ans)They are SLT Replication Application Servers to provide configuration information for data replication. This replication status can also be monitored.


    36).What is logging table?

    Ans)Logging table records all replicated changes in the table, which can be further replicated to the target system.


    37).How to define Transformation rules in HANA?

    Ans) Using advanced replication settings, transformation rules are specified to transfer data from source tables during replication process. For instance, setting rules to covert fields, fill vacant fields and skip records. These rules are structured using advanced replication settings (transaction IUUC_REPL_CONT)


    38).Explain the role of transaction manager and session?

    Ans)SAP HANA transaction manager synchronizes database transactions keeping the record of closed and open transactions. When a transaction is committed or rolled back, the manager informs all the active stores and engines about the action so that they can perform required actions in time.


    39). How is SQL statement processed in SAP HANA?

    Ans)Each SQL statement in SAP HANA is carried out in the form of a transaction. Every time, a new session is allocated to a new transaction. An operator is a special character that is used in SQL statement with WHERE clause for performing operations. The various operators in SAP HANA are logical, arithmetic, comparison, and set.


    40).Define Master-Controller job.

    Ans) A Master-controller job is responsible to build database logging table in the source system. It further creates synonyms and new entries in SLT server admin when the table loads / replicates.


    41).How users can avoid un-necessary storage of logging information?

    Ans)Pause the replication process and terminate the schema-related jobs.


    42).When to change the number of Data Transfer Jobs?

    Ans)The number of data transfer jobs change when the initial loading speed or latency replication time is not up to the mark. At the end of the initial load, the number of initial load jobs may be reduced.


    43). What is the default IMCE Studio perspective?

    Ans) Administrator Console


    44).What is the part of the transaction administrator and session?

    Ans)The exchange chief co-ordinates database exchanges and keeps a record of running and shut transactions. When the exchange is moved back or submitted, the exchange supervisor informs the included stockpiling motors about the occasion so they can run essential activities.


    45).Define Five-minute rule?

    Ans)It is a rule of thumb for deciding whether a data item should be kept in memory, or stored on disk and read back into memory when required. The rule is “randomly accessed disk pages of a cache are re-used every 5 minutes”.


    46).Tell something you know about Normalization and De-Normalization?

    Ans)Normalization is nothing but the process that is adopted for the purpose or removing the redundant data from the database. This is generally done by splitting the table into different sections. This actually makes sure of integrity. On the other side, the de-normalization is the process of considering the redundant data so that all the queries which are complex can be enhanced in terms of overall performance.


    47).Organizations have to spend a very large amount of money every year on database management, are you agree with this?

    Ans) Yes, this is totally right. However, it largely depends on the way a users is handling this approach. Basically, data management is a complex approach and there are a lot of tasks which are actually very critical. Managing the database without an effective tool is a big challenge. If an organization can consider a powerful tool like SAP HANA, a lot of tasks can be made simply and a ton of favorable outcomes can be derived simply.


    48).Why there is actually a need for the businesses to invest in a RDBMS tool in the present time?

    Ans)Managing the data is very important. In the present time, data plays an excellent role in the success of almost every business. Data helps in decision making, collaborations, start new ventures, tackling competition, improving quality and so on. There are a large number of other reasons as well that are mandatory for the business to get it done in a right manner. Thus management of data is important.


    49).By which command in SQL you can simply boost the visibility of the data in the database?

    Ans) This can be done simply by DCL benefits


    50).Name the two types of relational data which you can store in SAP HANA?

    Ans)It is possible for the users to store following two types of Data in the system

    1. Column Store
    2. Row Store

    There is not much difference between both and the users are free to consider the ones as per their need or the requirement.