SAP BW Interview Questions with Answers

Question.1  What is $ as an authorization value?

Answer:  You use $ followed by a variable name (values populated in user exit for bex); this avoids having too many roles.

Question.2  What is info object 0TCTAUTHH?

Answer:  This is used in hierarchy authorization

Question.3  How would you debug security issues?

Answer:  Using transactions ST01 and RSSiViTRACE; a ‘X’ mark in the log shows a failed authorization check.

Question.4  What are the data target administration tasks?

Answer: Delete index, generate index, construct database statistics, initial fill of new aggregates, roll up of filled aggregates, compression of the infocube, activate ODS, complete deletion of data target.

Question.5  What are the reporting agent tasks?

Answer:

exception reporting
print in the background
pre calculation of web templates
pre calculation of value sets

Question.6  What are the other BW processes?

Answer:

  • attribute change run
  • adjustment of time dependent aggregates
  • deletion of requests from PSA
  • reorganize attributes and texts for master data – this is a useful tool to compress master data and text.

Question.7  What are the parallel processes that could have locking problems?          

Answer:

  • hierarchy attribute change run.
  • loading master data for same info object; for example avoid loading master data from different source systems at the same time rolling up for same info cube.
  • selecting deletion of info cube/ODS and parallel loading.
  • activation or deletion of ODS object when loading parallel.

Question.8  What is ODS?

Answer: Operational Data Source: It used for detailed storage of data (like document level); you can overwrite existing data in ODS (in cube you cannot); you can also drill down-from cube to ODS; It is used for data consolidation and cleansing; the data is stored in a flat table (unlike the extended star schema of the cube);-so using SE11/SE16 you can query the ODS data directly.

Question.9   What is the use of change log?

Answer:  Change log is used for delta updates to the target; it stores all changes per request and updates the target.

Question.10  How do you delete change log?

Answer:  AWB -> right click on CDS -> Manage -> Environment -> Delete change log.

Question.11   What are the advantages of using ODS in a infoset for reporting?

Answer:

  • access via OLAP engine.
  • Infosets can Join flat BW objects- like master data attributes, etc

Question.12  What is the new features of ODS after version 3.x?

Answer:

  • you can load and activate ODS in parallel
  • No M table
  • Secondary indexes are created in CDS objects itself
  • Selective deletion.

Question.13  What is the use of BW statistics?

Answer:  The sets of cubes delivered by SAP is used to measure performance for query, loading data etc; it also-shows the usage of aggregates and the cost associated with them. Gives data on aggregates, OLAP and Warehouse management.

Question.14   How do you enable monitoring using BW statistics?

Answer:  Individual data providers can be enabled to minimize overhead; AWB -> Tools -> BW statistics

Question.15   How do you install BW statistics?

Answer: Use the business content to install. Using the Business Content section of AWB, select info area “BW Statistics”; right click and select insert objects for collections; select before and after data flow for grouping and install. Similarly install the Technical Content SAP_BW_TCONT role. Install the info package groups for Master data/text and transaction data.

Question.16   Give some examples’ of jqueries delivered with BW statistics?

Answer:

  • Mean time pdr query
  • Runtime query
  • Using iufocubes
  • Utilizing OLAP.

Question.17   What is the program to maintain?

Answer: RSDDS_AGGREGATES_MAINTAIN.

Question.18    What is “Roll Up” ?

Answer: Roll Up is the process by which requests loaded in to the info cube are relied to the aggregates; roll up is done, you cannot do a report on the request.

Question.19   What is the optimal size of the aggregates?

Answer:  It should have around 10-20% of the size of the fact table; for example if your fact table contains 1 million rows, the aggregate should have less than 200,000 rows.

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