Questions Answers For SAP Business Warehouse #1

Q) How can you improve the performance of a query?
 
A) Query Performance can be improved by making the Aggregates having all the Chars & KF used in Query.
 
Q) What is virtual cube? What its significance?
 
A) Virtual Cube : InfoProvider with transaction data that is not stored in the object itself, but which is read directly for analysis and reporting purposes. The relevant data can be from the BI system or from other SAP or non-SAP systems.  VirtualProviders only allow read access to data.
 
Q) What are the different methods of generic datasource?
 
A) Different Methods of Generic datasource using Transaction RSO2:
     a) Extraction from DB Table or View
     b) Extraction from SAP Query
     c) Extraction by Function Module
 
A) What are the important BW datasource relevant tables?
 
Q) Important BW datasource relevant tables:
 
ROOSOURCE: Table Header for SAP BW OLTP Sources
RODELTAM: BW Delta Process
ROOSFIELD: DataSource Fields
ROOSGEN: Generated Objects for OLTP Source, Last changed date and who etc.
 
Q) I want to delete a BEx query that is in Production system through request. Is anyone aware about it?
 
A) Have you tried the RSZDELETE transaction?
 
Q) Errors while monitoring process chains.
 
A) During data loading. Apart from them, in process chains you add so many process types, for example after loading data into Info Cube, you rollup data into aggregates, now this rolling up of data into aggregates is a process type which you keep after the process type for loading data into Cube. This rolling up into aggregates might fail.
 
Another one is after you load data into ODS, you activate ODS data (another process type) this might also fail.
 
Q) PSA Cleansing.
 
A) You know how to edit PSA. I don't think you can delete single records. You have to delete entire PSA data for a request.
 
Q) How much time does it take to extract 1 million (10 lackhs) of records into an infocube?
 
A) This depends, if you have complex coding in update rules it will take longer time, or else it will take less than 30 minutes.
 
Q) What is the landscape of BW?
 
Then Landscape of B/W: you have the development system, testing system, production system.
 
Development system: All the implementation part is done in this sys. (I.e., Analysis of objects developing, modification etc.) and from here the objects are transported to the testing system, but before transporting an initial test known as Unit testing (testing of objects) is done in the development system.
 
Testing/Quality system: quality check is done in this system and integration testing is done.
 
Production system: All the extraction part takes place in this system.
 
Q) How do you measure the size of infocube?
 
A: In number of records.
 
Q) Difference between infocube and ODS?
 
A: Infocube is structured as star schema (extended) where a fact table is surrounded by different dim table that are linked with DIM'ids. And the data wise, you will have aggregated data in the cubes. No overwrite functionality.
 
ODS is a flat structure (flat table) with no star schema concept and which will have granular data (detailed level). Overwrite functionality.
 
Flat file datasources does not support 0recordmode in extraction.
x before, -after, n new, a add, d delete, r reverse
 
Q) Can number of datasources have one infosource?
 
A) Yes of course. For example, for loading text and hierarchies we use different data sources but the same InfoSource.

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