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 write back capability.
BSO (Block Storage Option)-
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 these dense and sparse members are. When the intersections or cells of two dimensions mostly contain 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 product. 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.
Now the question arises what is the use of calling them dense or sparse. What difference does it make. Do some research and try to find the answer.
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 field 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 separate rule file for each dimension.
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.
8. 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.
9. How does UDA's impact database size?
Ans: Absolutely no impact as UDA’s does not require additional storage space.
10. 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 calculated dynamically.
11. 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.
12. 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.
13. 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.
14. 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: The record will be rejected.
15. 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.
16. Can we have multiple databases in one single application?
Ans: Yes. But only one database per application is recommended.
17. Can we have one ASO database and one BSO database in one single application. If yes, how and If No, why.
No. Because we define ASO or BSO option while creating the application and not database. Hence if the application is ASO, the databases it contains will be that type only.
18. What are the file extensions for an outline, rule file and a calc script.
Ans: .OTL, .RUL and .CSC
19. What is the role of provider services.
Ans: To communicate between Essbase and Microsoft office tools.
20. What is an alternative to create meta outline, rule file and load data.
Ans: Integration services and in version 11, we have Essbase studio.
21. Can we start and stop an application individually. How can this be used to increase performance.
Ans: Yes. We can manage our server resources by starting only the applications which receive heavy user traffic. When an application is started, all associated databases are brought to the memory.
22. We have created an application as unicode mode. Can we change it later to non-unicode mode.
Ans: No.
23. How can I migrate an application from my test environment to the production environment. Can I still do this if my test environment is a windows one and my production env is UNIX one. Also can I still do it if my test env and prod env versions are different.
Ans: Hyperion Administrative services console provides a migration utility to do this but only the application, database objects are migrated and no data is transferred. the answers to other two questions are Yes.
24. A customer wants to run two instances of an Essbase server on a same machine to have both test env and Development env on the same server. Can he do that?
Ans: Yes. We can have multiple instances of an Essbase server on a single machine and there will be different sets of windows services for all these instances.
25. suppose I have a dimension A with members B and C and I do not want B and C to roll up to A. how can I do this.
Ans: Using (~) exclude from consolidation operator.
26. What does never consolidate operator (^) do?
Ans: It prevents members from being consolidate across any dimension.
27. Can we have multiple meta outlines based on one OLAP model in Integration services?
Ans: Yes
28. Can we have an meta outline based on two different OLAP models.
Ans: No.
29. What is hybrid analysis?
Ans: Lower level members and associated data remains in relational database where as upper level members and associated data resides in Essbase database.
30. Why top-down calculation less efficient than a bottom-up calculation? Being less efficient, why do we use them.
Ans: In the process it calculates more blocks than is necessary. Sometimes it is necessary to perform top-down calculation to get the correct calculation results.
On what basis you will decide to invoke a serial or parellel calculation method.
Ans: If we have a single processor, we will use serial calculation but if we have multiple processors we can break the task into threads and make them run on different processors.
31. What is block locking system?
Ans: Analytic services (or Essbase Services) locks the block and all other blocks which contain the Childs of that block while calculating this block is block locking system.
32. What are the types of partitioning options available in Essbase?
Ans: 1. Replicated partition. 2. Transparent partition 3. Linked partition.
33. Dynamic calc decreases the retrieval time and increases batch database calculation time. How true is the statement?
Ans: The statement should be just opposite. As dynamic calc members are calculated when requested, the retrieval time should increase.
34. A customer has a cube with 13 dimensions and the performance was fine. Now they have added two more dimensions in the existing cube and the performance becomes very slow. Customer said logically nothing wrong with the two new dimensions they have added. What could be the reason for slow down.
Ans: Even I don't have any clue. I experienced this few days back with a customer. If you can throw some light on this, please post your answer
35. Can we have multiple meta outlines based on one OLAP model in Integration services?
Ans: Yes
36. What are LRO's( Linked Reporting Objects)?
Ans: They are specific objects like files, cell notes or URL's associated with specific data cells of Essbase database. You can link multiple objects to a single data cell. These linked objects are stored in the server. These LRO's can be exported or imported with the database for backup and migration activities.
37. What are the three primary build methods for building dimensions?
Ans:
1. Generation references
2. Level references
3. Parent-Child references
38. How does UDA's impact database size?
Ans: There will be no impact on the database as the UDA’s doesn’t store data in the database.
39. Can we have an meta outline based on two different OLAP models.
Ans: No.
40. Can we create UDA’s and apply it to Dense as well as Sparse dimensions?
Ans: Yes
41. Types of Partitions available in Essbase?
Ans: Three types of partitions are there.
1. Transparent partition: A form of shared partition that provides the ability to access and manipulate remote data transparently as though it is part of your local database. The remote data is retrieved from the data source each time you request it. Any updates made to the data are written back to the data source and become immediately accessible to both local data target users and transparent data source users
2. Replicated Partition
3. Linked Partition
44. What is hybrid analysis?
Ans: Lower level members and associated data remains in relational database where as upper level members and associated data resides in Essbase database.
45. Why top-down calculation less efficient than a bottom-up calculation? Being less efficient, why do we use them.
Ans: In the process it calculates more blocks than is necessary. Sometimes it is necessary to perform top-down calculation to get the correct calculation results.
46. On what basis you will decide to invoke a serial or parallel calculation method.
Ans: If we have a single processor, we will use serial calculation but if we have multiple processors we can break the task into threads and make them run on different processors.
47. How can you display UDA’s in reports?
Ans: UDA's values are never displayed in the reports and hence do not impact report performance.
48. 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: The record will be rejected.
49. What are the specified roles other than Administrator to view sessions, disconnect sessions or kill users requests for a particular application?
Ans: You should have the role of Application manager for the specified application.
50. What is block locking system?
Ans: Analytic services (or Essbase Services) locks the block and all other blocks which contain the Childs of that block while calculating this block is block locking system.
