50 REAL TIME SAP HANA Interview Questions and Answers

Sap Hana interview questions And Answers :-

 

1.What are the different types of replication techniques ?
2.What is SLT ?

SAP Hana Interview Questions And Answers

SAP Hana Interview Questions And Answers

3.Is it possible to load and replicate data from one source system to multiple target database schemas of HANA system ?
4.Is it possible to specify the type of data load and replication ?
5. What is Configuration in SLT ?
6. Is there any pre-requisite before creating the configuration and replication ?
7.What is Configuration and Monitoring Dashboard ?
8.What is advanced replication settings ?
9.What is Latency ?
10.What is logging table ?
11.What are Transformation rules ?
12.What happens when you set-up a new configuration ?
13.What factors influence the change/increase the number of jobs ?
14.When to change the number of Data Transfer jobs ?
15.What are the jobs involved in replication process ?
16.What is the relation between the number of data transfer jobs in the configuration settings and the available BGD work processes ?
 17.If you set the parameter “data transfer jobs” to 04 in a configuration “SCHEMA1”, a mass transfer ID 001 is assigned. Then what jobs should be in the system ?
 18.What happens after the SLT replication is over ?
 19.What are the different replication scenarios ?
20.What happens if the replication is suspended for a long period of time or system outage of SLT or HANA system ?
21.How to avoid unnecessary logging information from being stored ?
22.Will the table size in SAP HANA database and in the source system the same ?
23.When to go for table partitioning ?
24.Where do you define transformation rules ?
25.Are there any special considerations if the source system is non-SAP system ?
26.What are the potential issues in the creation of configuration ?
27.How can you ensure that data is consistent in source system and HANA system ?
28.Does SLT for SAP HANA support data compression like SAP HANA database ?
29. What are the product names?
30. What is SAP HANA Appliance 1.0?

31. What are the limitations of HANA 1.0?

Quite a few so far – it can only replicate certain data, from certain databases, in certain formats, using the Sybase Replication Server. Batch loading is done using SAP BusinessObjects Data Services 4.0 and is optimised only for SAP BusinessObjects BI 4.0 reporting.

32. What is SAP HANA 1.5, 1.2 or 1.0 SP03? 

These are all the same thing, and 1.0 SP03 is touted to be the final name for what should go into RampUp (beta) in Q4 2011. This will allow any SAP NetWeaver BW 7.3 Data Warehouse to be migrated into a HANA appliance. HANA 1.0 SP03 specifically also accelerates BW calculations and planning, which means you get even more performance gains.

33. What’s the difference between HANA and IMDB?

HANA is the name for the current BI appliance (HANA 1.0) and the BW Data Warehouse appliance (HANA 1.0 SP03). Both of these use the SAP IMDB Database Technology (SAP HANA Database) as their underlying RDBMS. Expect SAP to start to differentiate this more clearly as they start to position the technology for use cases other than Analytics.

34. If I can run Net Weaver BW on IMDB/HANA, why can’t I run the Business Suite/ERP 6.0?

Simply because it’s not mature enough yet to support business critical applications. From a technology perspective, it is already possible to run the Business Suite on IMDB and SAP has trialled moving some large databases into IMDB already.

35. What is HANA great at?

The best thing that HANA brings to the table is the ability to aggregate large data volumes in near real-time – and to have the data updated in near real-time. SAP’s demos show hundreds of billions of records of data being aggregated in a matter of seconds. SAP has built a set of Analytics Apps on top of HANA and this are set to be great point use cases to get customers up and running quickly.

36. 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.

  37. What does HANA cost?

SAP hasn’t entirely confirmed HANA licensing costs but the hardware is somewhere around $1-200k per TB. Add to this licensing cost which are still being made on a per-customer basis.

38. 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.

39. 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.

40. 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.

41. 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!

42. 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.

2. SAP HANA database hardware

43. 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.

44. 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!

45. 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.

46. 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.

47. 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.

48. 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.

49. 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.

50. 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.

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