Top 100 Hyperion Essbase Interview questions part-3



Here is part 3 of the series Top 100 Hyperion Essbase Interview questions pdf

51) In what case we can define generation 1 to a field in generation build method.
Answer

We cannot define that as Generation 1 is not valid.

52) 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.
Answer

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

53) Can we create more than 2 dimensions using only one build rule file.
Answer

Yes, we can do that but it is recommended to use separate rule file for each dimension.
54) Can we have multiple meta outlines based on one OLAP model in Integration services?
Answer
Yes

55) Can we have an meta outline based on two different OLAP models.
Answer
No.

56)  What is data block and index file in BSO database?

Answer The data block is the structure that is comprised of the dimensions tagged as dense in the Essbase outline (.otl file). The block is defined by the intersections of all dense dimension member intersections. When data blocks and index entries are persisted to disk, the data blocks are compressed and stored within ESS.PAG files and index entries are stored within ESS.IND files.

 

57) Can we create UDA’s and apply it to Dense as well as Sparse dimensions?
Answer Yes

58) What is block locking system?
Answer

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.

59) What are attributes?
Answer A classification of a member in a dimension. You can select and group members based on their associated attributes. You can also specify an attribute when you perform calculations and use calculation functions. Eg: The database in Sample Basic which has product dimension has some attributes like size, package type, and flavor. We can add these attributes to the dimensions where we can retrieve the data like for example to retrieve “coke with 8 Oz with bottles”, this is useful for generating reports.

60)  Why do objects gets locked and when does this happens?
Answer Objects gets locked to prevent users to make simultaneous and conflicting changes to Essbase database objects. By default, whenever an object is accessed through Administrative services console or Excel spreadsheet add-in, it gets locked.

61) When does Fragmentation occur?

Answer Fragmentation is likely to occur with the following:

  • Read/write databases that users are constantly updating with data
  • Databases that execute calculations around the clock
  • Databases that frequently update and recalculate dense members
  • Data loads that are poorly designed
  • Databases that contain a significant number of Dynamic Calc and Store members
  • Databases that use an isolation level of uncommitted access with commit block set to zero

 

62) How can you measure fragmentation?

Answer You can measure fragmentation using the average clustering ratio or average fragmentation Quotient.

Using the average fragmentation quotient

Any quotient above the high end of the range indicates that reducing fragmentation may help performance

Small (up to 200 MB) 60% or higher

Medium (up to 2 GB) 40% or higher

Large (greater than 2 GB) 30% or higher

Using the average clustering ratio:

The average clustering ratio database statistic indicates the fragmentation level of the data (.pag) files. The maximum value, 1, indicates no fragmentation.

63) How do you can prevent and remove fragmentation?

Answer

You can prevent and remove fragmentation:

  • To prevent fragmentation, optimize data loads by sorting load records based upon sparse dimension members. For a comprehensive discussion of optimizing data load by grouping sparse members.
  • To remove fragmentation, perform an export of the database, delete all data in the database with CLEARDATA, and reload the export file.
  • To remove fragmentation, force a dense restructure of the database.

64) What is database restructuring?

Answer

When you change the Essbase database outline to capture new product lines, provide information on new scenarios, reflect new time periods, etc. Some changes to a database outline affect the data storage arrangement, forcing Essbase to restructure the database.

65) What are the types of database restructuring?

Answer

The two ways by which a database restructure is triggered:

Implicit Restructures

Dense restructure

Sparse restructure

Outline-only restructure

Explicit Restructures

66) What are the conditions affecting Database restructuring?

Intelligent Calculation, name changes, and formula changes affect database restructuring:

  • If you use Intelligent Calculation in the database, all restructured blocks are marked as dirty whenever data blocks are restructured. Marking the blocks as dirty forces the next default Intelligent Calculation to be a full calculation.
  • If you change a name or a formula, Essbase does not mark the affected blocks as dirty. Therefore, you must use a method other than full calculation to recalculate the member or the database.

67) What are the files used during Restructuring?

Answer

When Essbase restructures both the data blocks and the index, it uses the files described

 

 Hyperion Essbase Interview questions pdf

68) What are the actions that improve performance for restructuring?

Answer

There are a number of things you can do to improve performance related to database restructuring:

a) If you change a dimension frequently, make it sparse. ·

b) Use incremental restructuring to control when Essbase performs a required database restructuring. ·

c) Select options when you save a modified outline that reduce the amount of restructuring required.

69) Why do objects gets locked and when does this happens?
Answer Objects gets locked to prevent users to make simultaneous and conflicting changes to Essbase database objects. By default, whenever an object is accessed through Administrative services console or Excel spreadsheet add-in, it gets locked.

70) I have created an application with one database in Essbase at test environment and now needs to copy the entire application with all security permissions to the production server which is not connected to the test server. How can I do that?
Answer: You can achieve this using migration wizard to migrate an application to a text file which you can take physically to the production server.

71) When I migrated the application to the production server I do not see any data in the Essbase database. What has gone wrong and how to correct this?
Answer Nothing has gone wrong. Migration utility does not migrate the actual data. If you want to copy the exact data from the test machine, get it exported using export utility and import it on production machine.

72) How can we backup an aggregate storage database?
Answer

a) shutdown the application

b) copy the application directory ARBORPATH/app/appname.c) startup the application

73) How does Essbase recover from a database crash?
Answer After a database crash or server interruption, Essbase automatically recovers a database after rolling back the transactions that were active at that time.

74) How can you make a Max L script run at a specified time?
Answer MaxL scripts can be called from a BAT file which is used for scheduling.

75)  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?
Answer

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.


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