The Below List of 100 REAL TIME SAP HANA Interview Questions and Answers Prepared by 6+ Years of Lead SAP HANA Developer
1.What is SAP HANA?
SAP HANA is an in-memory computing engine (IMCE) used for real-time processing of huge volumes of data and building and deploying real-world applications. Adopting the row-based and column-based DB technology, SAP HANA is an advanced relational DB product serviced by SAP SE. With this high-performance analytic (HANA) system, the big data exists on the main memory and not on the hard disk. It replaces the onus of data maintenance separately on the legacy system and simplifies the tasks of administrators in this digital world.
2.What is the development language used by SAP HANA?
C++
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 SAP HANA?
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.
5.List advantages of using SAP HANA database.
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 is Latency?
The total stretch of time consumed to replicate data from source system to target system is calculated as Latency.
9. 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.
10.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.
11.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.
12.Define Modeling Studio in SAP Hana Administration.
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.
13.List the different compression techniques in HANA?
Run-length encoding
• Cluster encoding
• Dictionary encoding
14.Explain SLT
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)
15. Name the replication jobs in SAP HANA.
Master Job (IUUC_MONITOR_)
• Data Load Job (DTL_MT_DATA_LOAD__2digits>)
• Master Controlling Job (IUCC_REPLIC_CNTR_)
• Migration Object Definition Job (IUCC_DEF_MIG_OBJ_2digits>)
• Access Plan Calculation Job (ACC_PLAN_CALC__2digits>)
16. What is Latency?
The time duration to perform data replication starting from the source to the target system is known as latency.
18.What are the various components of SAP HANA Administration?
SAP HANA Studio
• SAP HANA Application Cloud
• SAP HANA Cloud
• Sap HANA DB
19.How to perform backup and recovery operations?
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.
20.Define SLT Configuration
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.
21.What is Stall?
The waiting process for data to load from the main memory to the CPU cache is called Stall.
22.Define different types of information views.
There are primarily three types of information views in SAP HANA, which are all non-materialized.
• Attribute view
• Analytic view
• Calculation View
23.What are Configuration and Monitoring dashboard?
They are SLT Replication Application Servers to provide configuration information for data replication. This replication status can also be monitored.
24.What is logging table?
Logging table records all replicated changes in the table, which can be further replicated to the target system.
25.How to define Transformation rules in HANA?
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)
27.Explain the role of transaction manager and session?
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.
28.How is SQL statement processed in SAP HANA?
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.
Define Master-Controller job.
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.
30.How users can avoid un-necessary storage of logging information?
Pause the replication process and terminate the schema-related jobs.
31.Is the table size in source system and Sap HANA system same?
No
32.When to change the number of Data Transfer Jobs?
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.
33.What is the default IMCE Studio perspective?
Administrator Console
34. How does SAP HANA support import from a local file?
Go to File → Import, You will see below option
This is used to import data from a flat file like .xls or.csv file. Click on Next → Choose Target System → Define Import Properties.
Select Source file by browsing local system. It also gives an option if you want to keep the header row. It also gives an option to create a new table under existing Schema or if you want to import data from a file to an existing table.
35. Which of the export options allows you to export multiple packages locally or to other HANA system?
Delivery Unit:
Delivery unit is a single Unit which can be mapped to multiple packages and can be exported as single entity so that all the packages assigned to Delivery Unit can be treated as single unit.
36. What are the different modes in HANA studio that can be used for migration?
Change and Transport system
Delivery Unit
Developer Mode
SAP support mode
37. Which all Business Objects tools can be directly connected to HANA Information views?
SAP Lumira
Analysis edition for OLAP
SAP Crystal Reports
Design Studio
38. What are different recovery mechanism can be performed in HANA system?
Most Recent State − Used for recovering the database to the time as close as possible to the current time. For this recovery the data backup and log backup have to be available since last data backup and log area are required to perform the above type recovery.
Point in Time − Used for recovering the database to the specific point in time. For this recovery the data backup and log backup have to be available
since last data backup and log area are required to perform the above type recovery.
Specific Data Backup − Used for recovering the database to a specified data backup. Specific data backup is required for the above type of recovery option.
Specific Log Position − This recovery type is an advanced option that can be used in exceptional cases where a previous recovery failed.
Note − To run recovery wizard you should have administrator privileges on HANA system.
39. How you can connect SAP HANA to Microsoft Excel?
MDX Provider is used to connect MS Excel to SAP HANA database system. It provides driver to connect HANA system to Excel and is further used for data modelling. You can use Microsoft Office Excel 2010/2013 for connectivity with HANA for both 32 bit and 64 bit Windows.
40. How you can limit the size of data backup files in HANA system?
This can be done in File Based data backup settings. In Backup tab, go to Configuration → Limit Maximum file Size check box and enter the file size.
41. What is a restricted user in SAP HANA system?
Restricted users are those users who access HANA system with some applications and they don’t have SQL privileges on HANA system. When these users are created they don’t have any access initially.
If we compare restricted users with Standard users −
Restricted users can’t create objects in HANA database or their own Schemas.
They don’t have access to view any data in database as they don’t have generic Public role added to profile like standard users.
They can connect to HANA database only using HTTP/HTTPS.
42. How you can use Data provisioning in SAP HANA studio?
Go to SAP HANA Modeler Perspective → Data Provisioning.
43. What are the different modes in data provision in HANA Studio?
Load
Replicate
Suspend
Resume
44. What is SAP HANA Analytic Privileges?
Analytic Privileges are used to limit access on HANA Information views. You can assign different types of right to different users on different component of a View in Analytic Privileges.
45. What is a new calculated column in a HANA Modeling view?
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.
46. What is SAP HANA cockpit?
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
47. What is the use of Persistence layer in SAP HANA system?
Persistence layer provides inbuilt mechanism for disaster recovery in HANA system. It ensures that database is restored to most recent state in case of a system failure.
Persistence layer also manages data, transaction and configuration logs and backup of these files. Backups of data and log files are performed at save points and is normally scheduled every 5-10 minutes.
48. What are the different components in SAP HANA Architecture? What is the use of Index server?
Index Server
Name Server
Statistical Server
Preprocessor Server
XS Engine
SAP Host Agent
LM structure
SAP Solution Manager Diagnostic Agent
49. Which operating system is supported by HANA system?
Only operating system that is supported by HANA is Suse Linux Enterprise Server SP1/SP2 (SLES SP1/2).
50. What is HANA bad at?
There are some current issues around HANA when delivering ad-hoc analytics, especially when using the SAP Business Objects Webi tool. Essentially the problem is that you can ask computationally very difficult questions with Webi, which can cause very long response times with HANA. SAP will need to build optimization for both Webi and HANA to reduce the computational complexity of these questions, but they’re not there yet.
What’s more, it’s worth noting that HANA 1.0 is not a Data Warehouse and it is more of a Data Mart – that is, suited to point applications where there is a clear use case.
51. Why is HANA so fast?
Regular RDBMS technologies put the information on spinning plates of iron (hard disks) from which the information is retrieved. HANA stores information in electronic memory, which is some 50x faster (depending on how you calculate). HANA stores a copy on magnetic disk, in case of power
failure or the like. In addition, most SAP systems have the database on one system and a calculation engine on another, and they pass information between them. With HANA, this all happens within the same machine.
52. Does HANA/IMDB replace Oracle?
It’s the elephant in the room, but once the Business Suite runs on IMDB, Oracle won’t be needed any more by SAP customers 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.
53. What is this about 10:1 compression with HANA compared to Oracle?
A typical uncompressed Oracle or Microsoft SQL Server database, when put into HANA, will be 10x smaller than before and this is due to the way that HANA stores information in a compressed format. Note that most databases are now compressed and these numbers may not fit your scenario, and to add to this you need 2x the RAM as your database, plus room for growth. HANA sizing is still a dark art.
54. You mean I have to buy a HANA only 2.5x smaller than my big Oracle RDBMS? What about archiving and data ageing?
Yes, in some instances you may have to buy a HANA appliance that is only 2.5x smaller than it would be under Oracle. And data ageing isn’t part of the 1.0 release, but SAP is certainly working on it pretty hard. Let’s hope they release something faster than you need to buy a bigger HANA
appliance!
55. What’s the wider market opportunity for IMDB?
This is the interesting thing – no one knows yet, and few analysts seem to have cottoned on that the wider market opportunity might be huge. Think not just SAP applications but any third party that requires ultra-high speed. Think not just an appliance but a development platform. Time will tell.
56. 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.
57. 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!
58. 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.
59. 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.
60. 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 memory 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.
61. 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.
62. 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.
63. 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.
64. How to add a system to the SAP HANA Studio?
Manually: With this method, you add one SAP HANA system at a time.
In the Systems view, right-click any blank area and choose Add system...
Fill in the server name, instance number and system description, and choose Next.
Fill in the user name and password, and choose Finish.
By importing a Landscape: This method allows you to connect to several SAP HANA systems at the same time, by importing an xml file generated previously by a landscape export from the SAP HANA Studio installed on your computer or another one.
Choose File → Import and choose SAP HANA → Landscape.
Specify the landscape file location, the destination folder for the import, and choose Finish.
Note: The landscape xml file does not contain any password. You will have to specify the user and password for any system added to the Systems view.
65. What are the SAP HANA Studio perspectives?
The SAP HANA Administration Perspective: is a main view to administer HANA systems.
Start and stop a system
Configure a system
Monitor a system
Backup and restore a system
Perform a problem analysis
The SAP HANA Modeler Perspective: can create, manage, and transport information models (packages, information views, etc), define or extract data provisioning, configure the server, access SAP HANA documentation, etc.
The SAP HANA Development Perspective: Includes a development perspective with debugging functionality.
SAP HANA Extended Application Services (XS Server) is an application server, web server, and basis for an application development platform, that resides inside SAP HANA.
66. What is a Delivery Unit in SAP HANA?
Delivery unit is a single unit, which can be mapped to multiple packages and can be exported as single entity so that all the packages assigned to Delivery Unit can be treated as single unit.
Users can use this option to export all the packages that make a delivery unit and the relevant objects contained in it to a HANA Server or to local Client location.
The user should create Delivery Unit prior to using it.
This can be done through HANA Modeler → Delivery Unit → Select System and Next → Create → Fill the details like Name, Version, etc. → OK → Add
Packages to Delivery unit → Finish.
67. Explain SAP HANA Engines?
Run the Plan Visualization on your query to determine what engine is used to process a query.
Join Engine:
Used when querying an Attribute View and also when running SQL script.
OLAP Engine:
Used for Analytic view (without calculated or derived columns).
Calculation Engine:
Used for Calculation views and Analytic views with calculated attributes
68. Explain SAP HANA System Architecture?
The Index Server of the SAP HANA database is a core component that orchestrates the database's operations.
The Connection and Session Management which creates and manages sessions and connections for the database clients such as SAP BusinessObjects Reporting tools or applications.
The Transaction Manager coordinates transactions, controls transactional isolation, and keeps track of running and closed transactions.
Request Processing and Execution Control is a set of specialized engines and processors which handle the client requests are analyzed and executed.
SQL Processor receives the Incoming SQL requests and executes the Data Manaipulation Language (DML) statements - Insert, Select, Update, or Delete.
Metadata Manager handles Data Definition Lanaguage (DDL) statements, such as the definition of relational tables, columns, views, indexes and procedures.
Planning Engine handles Planning commands, wich allows financial planning apps to execute basic planning operations in the database layer.
Stored Procedure processor: handles procedure calls, which are written in SQLScript, a database programming language to execute application-specific calculations inside the database system.
MDX engine handles the Incoming MDX requests.
Calculation engine: Also handles the Incoming MDX requests, supports SQLScript, MD, and Planning operations.
Persistence layer component: manages the communication between the Index server and the File System that store the Data Volume and Transaction Log volume.
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.
The new Statistics Server is also known as the embedded Statistics Server or Statistics Service.
The new Statistics Server is now embedded in the Index Server.
69. Explain SAP HANA Software Optimization?
SAP applications are, of course, required to support not only SAP HANA but all databases which are certified for ABAP. For this reason, there is an enhancement in those ABAP programs which are SAP HANA optimized. In a Business Add-in (BAdI), those programs first check for the database in place.
In case of SAP HANA, the optimized version is triggered; in the other case the classical ABAP
flow is executed.
Thus there are two versions of certain processes on the application layer:
Standard ABAP code working on every supported database
Optimized ABAP code working on SAP HANA only
70. Explain SAP HANA deployment scenarios?
Side-by-side scenario: In the side-by-side scenario, the database tables that are used by the SAP HANA Live products need to be replicated from the corresponding SAP Business Suite back-end system into the SAP HANA database.
This is done using SAP Landscape Transformation Replication Server. If you want to execute SAP HANA Live views, the data from the corresponding tables must be available.
Integrated scenario: In the integrated scenario, you do not need to create and replicate the database tables, as they are already available in the SAP HANA database.
They are maintained through the data dictionary of the corresponding ABAP Application Server. Therefore, all steps regarding table creation and data replication are not relevant in this scenario.
71. When a SAP database is migrated to SAP HANA, in which table storage type do the tables get stored?
When a SAP system is migrated to SAP HANA, the SAP tables are automatically migrated into the storage type suited best. This logic is defined by SAP.
The majority of tables are held in the Column Store.
This information can be accessed in SAP HANA studio (Catalog > Open Definition) or in the technical settings of each table in the SAP dictionary (transaction SE13).
With column-based storage, data is only partially blocked. Therefore, individual columns can be processed at the same time by different cores.
72. How does SAP HANA compression work?
Apart from performance reasons, column store offers much more potential leverage state-of-the-art data compression concepts.
For example, SAP HANA works with bit encoded values and compresses repeated values, which results in much less memory requirements than for a classical row store table.
73. How SAP HANA handles Partitioning?
spreads table contents across the blades
work on smaller sets of data in parallel
74. What is SAP Information Composer?
SAP Information Composer is a web-based application that allows business to upload to and manipulate (clean, and model) data on the SAP HANA database.
The SAP HANA information composer uses a Java server, which interacts with the SAP HANA database. The Java server communicates with the SAP HANA information composer client via HTTP (port 8080) or HTTPS ( port 8443).
The SAP HANA information composer client is accessible to users who are assigned the IC_MODELER role. This role allows users to upload new content into the SAP HANA database and to create physical tables and calculation views.
75. Explain Persistence Layer within SAP HANA?
The persistence layer of SAP HANA relies on Data and Log volumes. The in-memory data is regularly saved to these volumes.
Data:
SQL data and undo log information
Additional HANA information, such as modeling data
Kept in-memory to ensure maximum performance
Write process is asynchronous
Log:
Information about data changes (redo log)
Directly saved to persistent storage when transaction is committed
Cyclical overwrite (only after backup)
Savepoint:
Changed data and undo log is written from memory to persistent storage
Automatic
At least every 5 minutes (customizable)
Data and log volumes are used as follows:
On a regular basis, data pages and before images (undo log pages) are written in the data volumes. This process is called a Savepoint.
Between two savepoints, after images (redo log pages) are written in the log volumes. This is done each time a transaction is committed.
Shadow paging is used to undo changes that were persisted since the last savepoint.
With the shadow page concept, physical disk pages written by the last savepoint are not overwritten until the next savepoint is successfully completed.
Instead, new physical pages are used to persist changed logical pages.
Until the next savepoint is complete, two physical pages may exist for one logical page:
The shadow page, which still contains the version of the last savepoint.
The current physical page which contains the changes written to disk after the last savepoint.
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| SAP HANA Interview Questions and Answers |
SAP HANA is an in-memory computing engine (IMCE) used for real-time processing of huge volumes of data and building and deploying real-world applications. Adopting the row-based and column-based DB technology, SAP HANA is an advanced relational DB product serviced by SAP SE. With this high-performance analytic (HANA) system, the big data exists on the main memory and not on the hard disk. It replaces the onus of data maintenance separately on the legacy system and simplifies the tasks of administrators in this digital world.
2.What is the development language used by SAP HANA?
C++
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 SAP HANA?
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.
5.List advantages of using SAP HANA database.
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 is Latency?
The total stretch of time consumed to replicate data from source system to target system is calculated as Latency.
9. 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.
10.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.
11.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.
12.Define Modeling Studio in SAP Hana Administration.
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.
13.List the different compression techniques in HANA?
Run-length encoding
• Cluster encoding
• Dictionary encoding
14.Explain SLT
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)
15. Name the replication jobs in SAP HANA.
Master Job (IUUC_MONITOR_)
• Data Load Job (DTL_MT_DATA_LOAD__2digits>)
• Master Controlling Job (IUCC_REPLIC_CNTR_)
• Migration Object Definition Job (IUCC_DEF_MIG_OBJ_2digits>)
• Access Plan Calculation Job (ACC_PLAN_CALC__2digits>)
16. What is Latency?
The time duration to perform data replication starting from the source to the target system is known as latency.
18.What are the various components of SAP HANA Administration?
SAP HANA Studio
• SAP HANA Application Cloud
• SAP HANA Cloud
• Sap HANA DB
19.How to perform backup and recovery operations?
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.
20.Define SLT Configuration
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.
21.What is Stall?
The waiting process for data to load from the main memory to the CPU cache is called Stall.
22.Define different types of information views.
There are primarily three types of information views in SAP HANA, which are all non-materialized.
• Attribute view
• Analytic view
• Calculation View
23.What are Configuration and Monitoring dashboard?
They are SLT Replication Application Servers to provide configuration information for data replication. This replication status can also be monitored.
24.What is logging table?
Logging table records all replicated changes in the table, which can be further replicated to the target system.
25.How to define Transformation rules in HANA?
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)
27.Explain the role of transaction manager and session?
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.
28.How is SQL statement processed in SAP HANA?
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.
Define Master-Controller job.
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.
30.How users can avoid un-necessary storage of logging information?
Pause the replication process and terminate the schema-related jobs.
31.Is the table size in source system and Sap HANA system same?
No
32.When to change the number of Data Transfer Jobs?
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.
33.What is the default IMCE Studio perspective?
Administrator Console
34. How does SAP HANA support import from a local file?
Go to File → Import, You will see below option
This is used to import data from a flat file like .xls or.csv file. Click on Next → Choose Target System → Define Import Properties.
Select Source file by browsing local system. It also gives an option if you want to keep the header row. It also gives an option to create a new table under existing Schema or if you want to import data from a file to an existing table.
35. Which of the export options allows you to export multiple packages locally or to other HANA system?
Delivery Unit:
Delivery unit is a single Unit which can be mapped to multiple packages and can be exported as single entity so that all the packages assigned to Delivery Unit can be treated as single unit.
36. What are the different modes in HANA studio that can be used for migration?
Change and Transport system
Delivery Unit
Developer Mode
SAP support mode
37. Which all Business Objects tools can be directly connected to HANA Information views?
SAP Lumira
Analysis edition for OLAP
SAP Crystal Reports
Design Studio
38. What are different recovery mechanism can be performed in HANA system?
Most Recent State − Used for recovering the database to the time as close as possible to the current time. For this recovery the data backup and log backup have to be available since last data backup and log area are required to perform the above type recovery.
Point in Time − Used for recovering the database to the specific point in time. For this recovery the data backup and log backup have to be available
since last data backup and log area are required to perform the above type recovery.
Specific Data Backup − Used for recovering the database to a specified data backup. Specific data backup is required for the above type of recovery option.
Specific Log Position − This recovery type is an advanced option that can be used in exceptional cases where a previous recovery failed.
Note − To run recovery wizard you should have administrator privileges on HANA system.
39. How you can connect SAP HANA to Microsoft Excel?
MDX Provider is used to connect MS Excel to SAP HANA database system. It provides driver to connect HANA system to Excel and is further used for data modelling. You can use Microsoft Office Excel 2010/2013 for connectivity with HANA for both 32 bit and 64 bit Windows.
40. How you can limit the size of data backup files in HANA system?
This can be done in File Based data backup settings. In Backup tab, go to Configuration → Limit Maximum file Size check box and enter the file size.
41. What is a restricted user in SAP HANA system?
Restricted users are those users who access HANA system with some applications and they don’t have SQL privileges on HANA system. When these users are created they don’t have any access initially.
If we compare restricted users with Standard users −
Restricted users can’t create objects in HANA database or their own Schemas.
They don’t have access to view any data in database as they don’t have generic Public role added to profile like standard users.
They can connect to HANA database only using HTTP/HTTPS.
42. How you can use Data provisioning in SAP HANA studio?
Go to SAP HANA Modeler Perspective → Data Provisioning.
43. What are the different modes in data provision in HANA Studio?
Load
Replicate
Suspend
Resume
44. What is SAP HANA Analytic Privileges?
Analytic Privileges are used to limit access on HANA Information views. You can assign different types of right to different users on different component of a View in Analytic Privileges.
45. What is a new calculated column in a HANA Modeling view?
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.
46. What is SAP HANA cockpit?
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
47. What is the use of Persistence layer in SAP HANA system?
Persistence layer provides inbuilt mechanism for disaster recovery in HANA system. It ensures that database is restored to most recent state in case of a system failure.
Persistence layer also manages data, transaction and configuration logs and backup of these files. Backups of data and log files are performed at save points and is normally scheduled every 5-10 minutes.
48. What are the different components in SAP HANA Architecture? What is the use of Index server?
Index Server
Name Server
Statistical Server
Preprocessor Server
XS Engine
SAP Host Agent
LM structure
SAP Solution Manager Diagnostic Agent
49. Which operating system is supported by HANA system?
Only operating system that is supported by HANA is Suse Linux Enterprise Server SP1/SP2 (SLES SP1/2).
50. What is HANA bad at?
There are some current issues around HANA when delivering ad-hoc analytics, especially when using the SAP Business Objects Webi tool. Essentially the problem is that you can ask computationally very difficult questions with Webi, which can cause very long response times with HANA. SAP will need to build optimization for both Webi and HANA to reduce the computational complexity of these questions, but they’re not there yet.
What’s more, it’s worth noting that HANA 1.0 is not a Data Warehouse and it is more of a Data Mart – that is, suited to point applications where there is a clear use case.
51. Why is HANA so fast?
Regular RDBMS technologies put the information on spinning plates of iron (hard disks) from which the information is retrieved. HANA stores information in electronic memory, which is some 50x faster (depending on how you calculate). HANA stores a copy on magnetic disk, in case of power
failure or the like. In addition, most SAP systems have the database on one system and a calculation engine on another, and they pass information between them. With HANA, this all happens within the same machine.
52. Does HANA/IMDB replace Oracle?
It’s the elephant in the room, but once the Business Suite runs on IMDB, Oracle won’t be needed any more by SAP customers 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.
53. What is this about 10:1 compression with HANA compared to Oracle?
A typical uncompressed Oracle or Microsoft SQL Server database, when put into HANA, will be 10x smaller than before and this is due to the way that HANA stores information in a compressed format. Note that most databases are now compressed and these numbers may not fit your scenario, and to add to this you need 2x the RAM as your database, plus room for growth. HANA sizing is still a dark art.
54. You mean I have to buy a HANA only 2.5x smaller than my big Oracle RDBMS? What about archiving and data ageing?
Yes, in some instances you may have to buy a HANA appliance that is only 2.5x smaller than it would be under Oracle. And data ageing isn’t part of the 1.0 release, but SAP is certainly working on it pretty hard. Let’s hope they release something faster than you need to buy a bigger HANA
appliance!
55. What’s the wider market opportunity for IMDB?
This is the interesting thing – no one knows yet, and few analysts seem to have cottoned on that the wider market opportunity might be huge. Think not just SAP applications but any third party that requires ultra-high speed. Think not just an appliance but a development platform. Time will tell.
56. 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.
57. 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!
58. 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.
59. 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.
60. 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 memory 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.
61. 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.
62. 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.
63. 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.
64. How to add a system to the SAP HANA Studio?
Manually: With this method, you add one SAP HANA system at a time.
In the Systems view, right-click any blank area and choose Add system...
Fill in the server name, instance number and system description, and choose Next.
Fill in the user name and password, and choose Finish.
By importing a Landscape: This method allows you to connect to several SAP HANA systems at the same time, by importing an xml file generated previously by a landscape export from the SAP HANA Studio installed on your computer or another one.
Choose File → Import and choose SAP HANA → Landscape.
Specify the landscape file location, the destination folder for the import, and choose Finish.
Note: The landscape xml file does not contain any password. You will have to specify the user and password for any system added to the Systems view.
65. What are the SAP HANA Studio perspectives?
The SAP HANA Administration Perspective: is a main view to administer HANA systems.
Start and stop a system
Configure a system
Monitor a system
Backup and restore a system
Perform a problem analysis
The SAP HANA Modeler Perspective: can create, manage, and transport information models (packages, information views, etc), define or extract data provisioning, configure the server, access SAP HANA documentation, etc.
The SAP HANA Development Perspective: Includes a development perspective with debugging functionality.
SAP HANA Extended Application Services (XS Server) is an application server, web server, and basis for an application development platform, that resides inside SAP HANA.
66. What is a Delivery Unit in SAP HANA?
Delivery unit is a single unit, which can be mapped to multiple packages and can be exported as single entity so that all the packages assigned to Delivery Unit can be treated as single unit.
Users can use this option to export all the packages that make a delivery unit and the relevant objects contained in it to a HANA Server or to local Client location.
The user should create Delivery Unit prior to using it.
This can be done through HANA Modeler → Delivery Unit → Select System and Next → Create → Fill the details like Name, Version, etc. → OK → Add
Packages to Delivery unit → Finish.
67. Explain SAP HANA Engines?
Run the Plan Visualization on your query to determine what engine is used to process a query.
Join Engine:
Used when querying an Attribute View and also when running SQL script.
OLAP Engine:
Used for Analytic view (without calculated or derived columns).
Calculation Engine:
Used for Calculation views and Analytic views with calculated attributes
68. Explain SAP HANA System Architecture?
The Index Server of the SAP HANA database is a core component that orchestrates the database's operations.
The Connection and Session Management which creates and manages sessions and connections for the database clients such as SAP BusinessObjects Reporting tools or applications.
The Transaction Manager coordinates transactions, controls transactional isolation, and keeps track of running and closed transactions.
Request Processing and Execution Control is a set of specialized engines and processors which handle the client requests are analyzed and executed.
SQL Processor receives the Incoming SQL requests and executes the Data Manaipulation Language (DML) statements - Insert, Select, Update, or Delete.
Metadata Manager handles Data Definition Lanaguage (DDL) statements, such as the definition of relational tables, columns, views, indexes and procedures.
Planning Engine handles Planning commands, wich allows financial planning apps to execute basic planning operations in the database layer.
Stored Procedure processor: handles procedure calls, which are written in SQLScript, a database programming language to execute application-specific calculations inside the database system.
MDX engine handles the Incoming MDX requests.
Calculation engine: Also handles the Incoming MDX requests, supports SQLScript, MD, and Planning operations.
Persistence layer component: manages the communication between the Index server and the File System that store the Data Volume and Transaction Log volume.
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.
The new Statistics Server is also known as the embedded Statistics Server or Statistics Service.
The new Statistics Server is now embedded in the Index Server.
69. Explain SAP HANA Software Optimization?
SAP applications are, of course, required to support not only SAP HANA but all databases which are certified for ABAP. For this reason, there is an enhancement in those ABAP programs which are SAP HANA optimized. In a Business Add-in (BAdI), those programs first check for the database in place.
In case of SAP HANA, the optimized version is triggered; in the other case the classical ABAP
flow is executed.
Thus there are two versions of certain processes on the application layer:
Standard ABAP code working on every supported database
Optimized ABAP code working on SAP HANA only
70. Explain SAP HANA deployment scenarios?
Side-by-side scenario: In the side-by-side scenario, the database tables that are used by the SAP HANA Live products need to be replicated from the corresponding SAP Business Suite back-end system into the SAP HANA database.
This is done using SAP Landscape Transformation Replication Server. If you want to execute SAP HANA Live views, the data from the corresponding tables must be available.
Integrated scenario: In the integrated scenario, you do not need to create and replicate the database tables, as they are already available in the SAP HANA database.
They are maintained through the data dictionary of the corresponding ABAP Application Server. Therefore, all steps regarding table creation and data replication are not relevant in this scenario.
71. When a SAP database is migrated to SAP HANA, in which table storage type do the tables get stored?
When a SAP system is migrated to SAP HANA, the SAP tables are automatically migrated into the storage type suited best. This logic is defined by SAP.
The majority of tables are held in the Column Store.
This information can be accessed in SAP HANA studio (Catalog > Open Definition) or in the technical settings of each table in the SAP dictionary (transaction SE13).
With column-based storage, data is only partially blocked. Therefore, individual columns can be processed at the same time by different cores.
72. How does SAP HANA compression work?
Apart from performance reasons, column store offers much more potential leverage state-of-the-art data compression concepts.
For example, SAP HANA works with bit encoded values and compresses repeated values, which results in much less memory requirements than for a classical row store table.
73. How SAP HANA handles Partitioning?
spreads table contents across the blades
work on smaller sets of data in parallel
74. What is SAP Information Composer?
SAP Information Composer is a web-based application that allows business to upload to and manipulate (clean, and model) data on the SAP HANA database.
The SAP HANA information composer uses a Java server, which interacts with the SAP HANA database. The Java server communicates with the SAP HANA information composer client via HTTP (port 8080) or HTTPS ( port 8443).
The SAP HANA information composer client is accessible to users who are assigned the IC_MODELER role. This role allows users to upload new content into the SAP HANA database and to create physical tables and calculation views.
75. Explain Persistence Layer within SAP HANA?
The persistence layer of SAP HANA relies on Data and Log volumes. The in-memory data is regularly saved to these volumes.
Data:
SQL data and undo log information
Additional HANA information, such as modeling data
Kept in-memory to ensure maximum performance
Write process is asynchronous
Log:
Information about data changes (redo log)
Directly saved to persistent storage when transaction is committed
Cyclical overwrite (only after backup)
Savepoint:
Changed data and undo log is written from memory to persistent storage
Automatic
At least every 5 minutes (customizable)
Data and log volumes are used as follows:
On a regular basis, data pages and before images (undo log pages) are written in the data volumes. This process is called a Savepoint.
Between two savepoints, after images (redo log pages) are written in the log volumes. This is done each time a transaction is committed.
Shadow paging is used to undo changes that were persisted since the last savepoint.
With the shadow page concept, physical disk pages written by the last savepoint are not overwritten until the next savepoint is successfully completed.
Instead, new physical pages are used to persist changed logical pages.
Until the next savepoint is complete, two physical pages may exist for one logical page:
The shadow page, which still contains the version of the last savepoint.
The current physical page which contains the changes written to disk after the last savepoint.
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