Hello friends if you are looking for SAP HANA Interview Questions then here you will get the SAP HANA Multiple Choice questions | SAP HANA interview Questions with answers | Sap HANA interview questions for experienced | SAP HANA real time Interview Questions | Deloitte SAP HANA technical Interview Questions then here you will get answers for it
If you did not visited interview questions list which is already published by us have look that also – SAP HANA Interview Question Answers
What hardware is supported right now?
Talk to your hardware vendor – all of the major vendors e.g. HP, IBM, Dell, have HANA offerings now. Technically HANA will run on any Intel x64 based system from your laptop through to the big 40-core, 2TB RAM servers. It is however only supported on a small number of big rack-mount servers like the Dell R910 and HP DL980.
Why doesn’t HANA run on blades?
It’s unclear but probably because the blades don’t yet offer the same performance. HANA is optimized for the Intel X7560 CPU and will run fastest on this. And for instance, the Dell M910 blade can only run 2x X7650 CPUs and 512 GB RAM in this configuration, which probably explains the limitations. What’s certain is that HANA will eventually run on blades – it’s born to run on blade technology!
Does SAP make their own IMDB/HANA hardware?
Yes, but only in the labs so far. There are no public plans to compete against
IBM/HP/Dell in this space, but it may make sense for SAP to enter the appliance market,
especially in the context of Data Centres and even more so in the context of the SAP
Business by Design cloud offering, which will run on IMDB.
How big does HANA scale?
Theoretically at least – very well. The biggest single-server HANA hardware will run
most mid-size workloads – 2TB of in-memory storage is equivalent to 5-20TB of Oracle
storage. The way that HANA works means that it is possible to chain multiple systems
together – meaning that scalability has thus-far been determined by the size of customers’
wallets. Do note that whilst SAP talk up “Big Data” quite a lot, HANA currently only
scales to the small-end of Big Data, which refers to the kind of huge datasets that Face
Book or Google have to store – not Terabytes, but rather Peta bytes.
What storage subsystem does HANA use?
This varies from vendor to vendor but it is shared network attached storage (NAS). Both
regular magnetic disks and SSD storage can be used for the backup of the database
(HANA runs in memo, remember, so disk storage is just for backup, and later, for data
ageing). Note that you require 2x storage that you have RAM, which is 2x the database
size – i.e. storage size = 4x database size. In most cases there is additional ultra-high
speed SSD storage for log files.
What source databases does HANA support in real-time?
If you use Sybase Replication Server (SRS) for near real-time data then you need to
watch out for licensing still (SAP have license deals pending). If you run DB2 then you’re fine but with Oracle and Microsoft SQL Server there are some license challenges
if you buy your license through SAP, because you may have a limited license that does
not allow extraction. Talk to SAP for further information on this.
What source databases does HANA support for batch loads?
If you use SAP Business Objects Data Services 4.0 for bulk loads then pretty much
anything. BO-DS is a very flexible Extract, Transform & Load tool that supports many
databases – check out the specs for more details.
What additional limitations does Sybase Replication Server present?
SRS has additional restrictions which are worth bearing on mind. It can only replicate
Unicode data and does not support IBM DB2 compressed tables.
Is there any pre-requisite before creating the configuration and replication?
For SAP source systems:
1.DMIS add-on must be installed in SLT replication server
- An RFC connection between the SAP source system and the SAP LT Replication
Server has to be established. - User for RFC connection must have the role IUUC_REPL_REMOTE assigned.
- Do not use a DDIC user for RFC connection.
For non-SAP source systems:
- DMIS add-on is not required.
- A database user has to be created with appropriate authorizations in advance and
establish the database connection by using transaction DBCO in the SAP LT Replication
Server. - Ensure the database-specific library components for the SAP 7.20 REL or EXT kernel
are installed in the SAP LT Replication Server.
What is Configuration and Monitoring Dashboard?
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).
What is advanced replication Let_it (t,saction IUUC_REPL_CONT)?
The Advanced Settings (transaction IUUC,2REPL_CONT) allows you to define and
change various table settings for a configuration such as:
- Partitioning and structure changes for target tables in HANA
- Table-specific transformation and filter rules
- Adjusting the number of jobs (nd reading type) to accelerate the load application
process
What is Latency?
It is the length of time to replicate data (a table entry) from the source system to the target system.
Mention what is the role of the transaction manager and session?
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.
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.
Explain how SQL statement is processed?
In the HANA database, each SQL statement is implemented in the reference of the transaction. New session is allotted to a new transaction.
Name various components of SAP HANA?
· SAP HANA DB
· SAP HANA Studio
· SAP HANA Appliance
· SAP HANA Application Cloud
When is table partitioning opted?
if the table size in HANA database exceeds 2 billion records, the table should be
splitted by using portioning features by using Advanced replication settings (transaction
IUUC_REPL_CONT, tab page IUUC_REPL_TABSTG).
What are the row-based and column based approach?
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
In HANA which type of tables should be preferred – Row-based or Column-based?
SQL queries involving aggregation functions take a lot of time on huge amounts of data
because every single row is touched to collect the data for the query response.
In columnar tables, this information is stored physically next to each other, significantly
increasing the speed of certain data queries. Data is also compressed, enabling shorter
loading times.
Conclusion:
To enable fast on-the-fly aggregations, ad-hoc reporting, and to benefit from
compression mechanisms it is recommended that transaction data is stored in a column-
based table.
The SAP HANA data-base allows joining row-based tables with column-based tables.
However, it is more efficient to join tables that are located in the same row or column
store. For example, master data that is frequently joined with transaction data should
also be stored in column-based tables.
Why materialized aggregates are not required in HANA?
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
-Simplified application logic
-Higher level of concurrency
How to avoid unnecessary logging information from being stored?
replication by stopping the schema-related jobs
Will the table size in SAP HANA database and in the source system the same?
No. As HANA database supports compression, the table size in SAP HANA may be
decreased.
When to go for table partitioning?
If the table size in HANA database exceeds 2 billion records, split the table by using
portioning features by using “Advanced replication settings” (transaction
IUUC_REPL_CONT, tab page IUUC_REPL_TABSTG).
Where do you define transformation rules?
By using “Advanced replication settings’. (transaction IUUC_REPL_CONT, tab page
IUUC ASS RULE MAP)
Are there any special considerations if the source system is non-SAP system?
The concept of trigger-based replication is actually meant for SAP source systems. The
main differences are: There will be a database connection between non-SAP source and
SLT system instead of RFC. Source must have primary key Tables DDO2L, DDO2T
which contains metadata are just initially loaded but not replicated. The read modules
reside on SLT system. Tables with database specific formats may need transformation
rules before they are replicated. Only SAP supported databases are supported as non-
SAP source systems.
Does SLT for SAP HANA support data compression like SAP HANA database?
Yes, this is automatically covered by the RFC connection used for data replication from
the SAP source system
Will the table size in SAP HANA database and in the source system the same?
No as HANA database supports compression.
How can you ensure that data is consistent in source system and HANA system?
Since any changes in the source system is tracked in dedicated logging tables, the
replication status for each changed data 4 record is transparent. A entry of logging table
is deleted after a successful commit statement from HANA database and this procedure
ensures the data consistency between source system and HANA system.
Describe SAP HANA Database Architecture in brief.
The SAP HANA database is developed in C++ and runs on SUSE Linux Enterprise
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, Pre-processor 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.
Pre-processor Server:
The index server uses the pre-processor 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.
What is the SAP HANA Enterprise Cloud?
The SAP HANA Enterprise Cloud offering is a comprehensive cloud infrastructure combined with managed services. Customers can now run their SAP HANA applications, including SAP Business Suite powered by SAP HANA and SAP NetWeaver Business Warehouse powered by SAP HANA, in a managed cloud environment. It delivers the power of real-time in-memory technology with cloud simplicity. SAP HANA Enterprise Cloud is a fully scalable, enterprise-ready, mission critical, secure, and high availability cloud offering with a full-managed services approach. The company’s flagship SAP HANA platform is at the heart of this offering. Customers will be able to accelerate their innovation cycles by relying on SAP and certified SAP HANA Enterprise Cloud partners.
How is this related to the Petabyte Farm?
SAP HANA Enterprise Cloud is the commercial name for the Petabyte Farm. In addition to the infrastructure, which is the world largest cluster of in-memory servers, SAP has innovated on deployment flexibility (“cloud frame technology”) and managed services to assess, onboard, and run customers with high performance.
Why has SAP announced SAP HANA Enterprise Cloud?
SAP is committed to establishing SAP HANA as the de facto modern data platform in
the market. Our intent is to help accelerate adoption of SAP HANA through an open
ecosystem strategy. The SAP HANA Enterprise Cloud offering will help customers
reduce the lead time and distractions typically encountered waiting for hardware, hiring
specialized skills for migrations and operations, and building solid deployment plans.