Oracle Hyperion Essbase Interview Questions | Part-1

1: What are the two storage options available in Essbase and what are the differences?

Ans: ASO( Aggregate Storage Option) - Used for 

1. If we have large number of dimensions(generally more than 10) 

2. Most of the dimensions are sparse 

3. We cannot write back in ASO. I heard recently that ASO will also have the writeback capability.

BSO (Block Storage Option) - Used For

1. Dimensions are less and dense(recommended values for no of dim are between 4 and 8) . 2. We can write back hence much suited for planning applications.

Financial applications are generally dense structures and normal analytical cubes are sparse. Here we also need to understand what are these dense and sparse members. When the intersections or cells of two dimensions mostly contains a value it is dense. Say for example we have two dimensions period(Month or quarter) and region and we are calculation the sales amount. Generally maximum regions(countries, cities) will have some sales value for a particular month or quarter. Hence we can say that our period dimensions would be dense. But now instead of period, consider another dimension products. Now there are some products which are sold in only some particular regions hence for them there will be no values in other regions or will have very low percentage of data values hence the structure will become sparse.

2: Can we build dimensions directly from data sources without using rule files.

Ans: No.

3: When do we generally use build rules files?

Ans: To automate the process of creating dimensions with thousands of members.

4: What are the three primary build methods for building dimensions?

Ans: 1. Generation references

2. level references

3. Parent-Child references.

5: In what case we can define generation 1 to a feild in generation build method.

Ans: We cannot define that as Generation 1 is not valid.

6: Suppose we have assigned Generation 2 and Generation 4 as of now and think of adding generation 3 later some time. Can we build the dimension ?

Ans: No. If gen 2 and gen 4 exists, we must assign gen 3.

7: Can we create more than 2 dimensions using only one build rule file ?

Ans: Yes, we can do that but it is recommended to use seperate rule file for each dimension.

8: What is UDA( user defined attributes). How are they different than Aliases ?

Ans: UDA represents the class of the members. Aliases are just another names of the members. both are different and has different usage.

9: Can we query a member for its UDA in a calculation script.

Ans: Yes. You can query a member for its UDA in a calculation script.

10: How does UDA's impact database size?

Ans: Absolutely no impact as UDA's do not require additional storage space.

11: What is the difference between UDA's and Attribute dimensions?

Ans : Attribute dimensions provides more flexibility than UDA's. Attribute calculations dimensions which include five members with the default names sum, count, min, max and avg are automatically created for the attribute dimensions and are calculate dynamically.

12: How does Attribute dimensions and UDA's impact batch calculation performance?

Ans: UDA's- No Impact as they do not perform any inherent calculations.

Attribute dim- No Impact as they perform only dynamic calculations.

13: How can we display UDA's in reports? How do they impact report report performance ?

Ans: UDA's values are never displayed in the reports and hence do not impact report performance.

14: How does Attribute dim impact report performance?

Ans: They highly impact the report performance as the attributes are calculated dynamically when referenced in the report. For very large number of att dim displayed in the report, the performance could drastically reduce.

15: While loading the data, you have applied both the selection criteria as well as rejection criteria to a same record. What will be the outcome.

Ans: Thw record will be rejected.

16: How is data stored in the Essbase database?

Ans: Essbase is an file based database where the data is stored in PAG files of 2 GB each and grows sequentially.

17: Can we have multiple databases in one single application?

Ans: Yes. But only one database per application is recommended.

18: Can we have one ASO database and one BSO database in one single application. If yes, how and If No, why.

Ans: No. Because we define ASO or BSO option while creating the appication and not database. Hence if the application is ASO, the databases it contains will be that type only.

19: What are the file extensions for an outline, rule file and a calc script.

Ans: .OTL, .RUL and .CSC

20: What is the role of provider services.

Ans: To communicate between Essbase and Microsoft office tools.