SAP HANA Interview Questions and Answers for Experienced

Question.1  What is the performance on SAP HANA One as compared to SAP HANA on-premise?

Answer:  For a similar number and type of CPU cores, memory and I/O configuration, SAP HANA One is comparable to SAP HANA on-premise. Your actual performance will vary based on the nature of workload.

Question.2  If SAP or another source system is connecting from onsite to SAP HANA One, what is the network bandwidth?

Answer:  Network bandwidth in this case is dependent on the bandwidth available at the onsite location.

Question.3 What happens if there’s a hardware failure? Who is responsible, SAP or Amazon? What should a customer do?

Answer:  If your SAP HANA One instance fails, you can start up again using the AWS Console or through an API call. All storage volumes associated with your instance are automatically attached to your new instance.

Question.4  How do I recover lost data?

Answer:  SAP HANA One is configured to back up data and log to a separate 200GB EBS volume from which data can then be recovered. Log backup is performed periodically as needed. Data backup is recommended periodically and before any system upgrade to protect data and HANA artifacts.

Question.5  What happens to my data when I shut down the SAP HANA One instance?

Answer:  The SAP HANA One instances are backed up by persistent data stores and volumes and will remain attached until the user terminates the instance. Once the instance is terminated, by default, only the root volume is deleted. The data, log, and backup volumes are not deleted automatically. Those volumes can be attached to other instances if required. If the instance is not needed anymore, make sure to delete all the EBS volumes to avoid storage charges for unused EBS volumes.

Question.6  Can a SAP HANA One backup be restored into an on-premise instance of SAP HANA?

Answer:  Yes, as long as SAP HANA One and SAP HANA on-premise licenses are valid, and the SAP HANA versions match, backup data can be transferred. Please follow your license agreements carefully before you transfer any data between SAP HANA One and SAP HANA on-premise.

Question.7  Do I need to install Secure Backup media and administrative servers in order to do Cloud backup?

Answer:  Special backup media is not required. The SAP HANA One instances are pre-configured with 200GB of EBS volumes for data backups. For added data security, snapshots of these volumes can be created on AWS.

Question.8  What process do I need to follow to become an SAP HANA One OEM Partner?

Answer: To become an SAP OEM Partner, please apply for OEM partner application at: http://www.sap-web.com/forms/Q210/partners/applicatio

Question.9  What is SAP Collections Insight?

Answer: SAP Collections Insight powered by SAP HANA allows you access to real-time mobile collaboration and collections account information anywhere and anytime, allowing you to resolve collections issues, better manage your collections efforts, tighten business relationships and get paid faster.

Question.10  What are the benefits of having a collections management solution powered by SAP HANA?

Answer:  SAP HANA is able to bring massive amounts of detailed data from source systems, directly into memory, where translation, mapping and synchronization can be done in real-time, without the need for pre-aggregations and data duplication. This allows users to plan rapidly and iteratively using their complete, detail-level data-spending less time collecting and assembling data and more time making the critical decisions that drive their business.

Question.11  What are the business benefits of SAP Collections Insight?

Answer:  The SAP Collections Insight web and mobile apps give you access to rich, dynamic account profiles and enable real-time analysis of payments and payment trends across years of data. With Collections Insight, sales and service teams can support collections activities with access to dashboards and collaborative tools to help manage, track, quickly resolve collections issues, and get paid on outstanding accounts faster.

Question.12  How is the solution delivered?

Answer:  SAP Collections Insight is delivered as mobile and web applications, powered by SAP HANA, letting our customers access the power of SAP HANA in an easy-to-consume model. This leads to radical reductions in capital expenditure and quicker innovation cycles.

Question.13  Describe SAP HANA Database Architecture in brief?

Answer:  The SAP HANA database is developed in C++ and runs on SUSE Linux Enterpise Server. SAP HANA database consists of multiple servers and the most important component is the Index Server. SAP HANA database consists of Index Server, Name Server, Statistics Server, Preprocessor Server and XS Engine.

Index Server:

Index server is the main SAP HANA database component

It contains the actual data stores and the engines for processing the data.

The index server processes incoming SQL or MDX statements in the context of authenticated sessions and transactions.

Persistence Layer:

The database persistence layer is responsible for durability and atomicity of transactions. It ensures that the database can be restored to the most recent committed state after a restart and that transactions are either completely executed or completely undone.

Preprocessor Server:

The index server uses the preprocessor server for analyzing text data and extracting the information on which the text search capabilities are based.

Name Server:

The name server owns the information about the topology of SAP HANA system. In a distributed system, the name server knows where the components are running and which data is located on which server.

Statistic Server:

The statistics server collects information about status, performance and resource consumption from the other servers in the system.. The statistics server also provides a history of measurement data for further analysis.

Session and Transaction Manager:

The Transaction manager coordinates database transactions, and keeps track of running and closed transactions. When a transaction is committed or rolled back, the transaction manager informs the involved storage engines about this event so they can execute necessary actions.

XS Engine:

XS Engine is an optional component. Using XS Engine clients can connect to SAP HANA database to fetch data via HTTP.

Question.14  So is SAP making/selling the software or the hardware?

Answer: SAP has partnered with leading hardware vendors (HP, Fujitsu, IBM, Dell etc) to sell SAP certified hardware for HANA: SAP is selling licenses and related services for the SAP HANA product which includes the SAP HANA database, SAP HANA Studio and other software to load data in the database.

Question.15  What is the language SAP HANA is developed in?

Answer:  The SAP HANA database is developed in C++.

Question.16  What is the operating system supported by HANA?

Answer: Currently SUSE Linux Enterprise Server x86-64 (SLES) 11 SP1 is the Operating System supported by SAP HANA.

Question.17  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.

Question.18  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. Following figure explains the difference between the two storage mechanism. Column based and Row based Tables.

Question.19  What are the advantages and disadvantages of row-based tables?

Answer:

Row based tables have advantages in the following circumstances:

The application needs to only process a single record at one time (many selects and/or updates of single records). The application typically needs to access a complete record (or row). Neither aggregations nor fast searching are required. The table has a small number of rows (e. g. configuration tables, system tables). Row based tables have dis-advantages in the following circumstances: In case of analytic applications where aggregation are used and fast search and processing is required. In row based tables all data in a row has to be read even though the requirement may be to access data from a few columns.