Interview Questions and Answers -3

What is the data modelling tool in MSTR called?

 Architect

How do we migrate objects across projects?

Object Manager

What is the difference between object manager and project merge?

o    Object Manager can move just a few objects or just the objects in a few folders. Project Merge moves all the objects in a project.

o    Object Manager must locate the dependents of the copied objects and then determine their differences before performing the copy operation. Project Merge does not do a dependency search, since all the objects in the project are to be copied.

o    Project Merge can be run from the command prompt in Microsoft Windows.

What is a history list?

The portion of the interface that allows users to retrieve the results of previously executed or scheduled reports.

What is difference between purging and deleting cache?

Caching allows for improved performance in response to report queries. Although the use of caching is an advantage, there are instances when caches may expire or become invalid. Some of these instances are:

When there are changes made to the objects in the data warehouse, the existing caches may be configured so that they are no longer valid when hitting certain warehouse tables. Any further report execution will no longer hit the cache.

When the definition of an application object changes (such as a report definition, report, template, metric definition, etc.), the related report cache is marked as invalid.

When there is a need to control the growth of caches on the Microstrategy Intelligence Server, old caches may need to be expired automatically.

Invalidating Report Caches

Invalidation is a preventive measure that renders a cache unusable by nullifying it. Cache invalidation only applies to Matching caches and Matching-History caches. It makes the cache ineligible in the matching process so it is not used to fulfill a report request.

In the case of a Matching cache, invalidating it will automatically result in deleting it.

In the case of a Matching-History cache, invalidation simply converts it to a History cache that is not used in the matching process any more but is still accessible through History List messages that reference it. However, if all these messages are deleted, the converted History cache that is referenced is also deleted.

Expiring Report Caches

Cache expiration is a process that renders a cache unusable by terminating its useful life. It yields the same results as invalidating a cache and applies to Matching caches and Matching-History caches. Cache expiration occurs automatically as per the 'Report cache duration' setting which can be found under Project Configuration > Reports >Advanced > Caching.

When a cache is updated, the current cache lifetime is used to determine the cache expiration date based on the last update time of the cache. This means that changing the Report cache duration setting does not affect the expiration date of the already existing caches. It only affects the new caches that are being or will be processed.

 Deleting Report Caches

Cache deletion is a process that deletes the cache from memory as well as disk. Report caches are automatically deleted by MicroStrategy Intelligence Server if cache invalidation and History Lists are performed and maintained properly.

In the case of a History cache, deleting it does not automatically delete the associated History List messages that reference it. After deleting a History cache, when a message that references it is retrieved, the following occurs:

 MicroStrategy Web users see an error message, "Execution results not available. Would you like to re-execute?"

MicroStrategy Desktop users do not see the above error message because MicroStrategy Desktop automatically resubmits the report for execution.

On the other hand, a History cache is automatically deleted when all the History List messages that reference it are deleted (when its History List reference count reaches 0).

In the case of a Matching-History cache, when all the History List messages that reference it are deleted, it is simply converted to a Matching cache, while losing its History component.

Caches can be deleted:

Manually - via Cache Monitor and MicroStrategy Command Manager

Scheduled - via MicroStrategy Cache Administration Utility

Scheduled - via MicroStrategy Desktop Scheduled Administrative Task.

Purging Report Caches

Cache Purging is a process whereby all report caches can be deleted in bulk, even the one references by History List messages.

How to apply row level security?

Applying Security filters to the user. This provides row level security

When do we go for schema update?

 When any of the schema objects are modified – Attributes/Facts/ Transformations/Tables/Hierarchies/Partitions

When New Tables are added to the schema using warehouse catalog.

When you update the structure of existing tables in the warehouse   catalog.

What are VLDB properties?

VLDB stands for Verly Large Data Base Properties. This is Microstartegy way of handling database specific preferences while generating the report SQL. There are number of them. A few common one are for Attribute or Metric join types, cross join check, type of intermediate table, etc.

At which levels you can set the VLDB properties? Which level has the highest pecedence?

VLDB Properties can be set at various levels like Report, Template, Metric, Project, Database Instance and DBMS level. Out of this Report level has the highest priority. It overrides all other levels.

What are the various ways of incorporating security in Microstrategy?
In Microstrategy security can be incorporated using a mix of any of the following ways:

·         Putting user specific restrictions at the database end and using user specific connection mapping. This is for column level security.

·         Applying folder and object level security to restrict access to certain set of reports/objects

·         Applying Security filters to the user. This provides row level security.

Object Level

Folder Level

Row Level

How conflicts occur and what the ways to resolve them?

When copying objects across projects with Object Manager, if an object with the same ID as the source object exists anywhere in the destination project, a conflict occurs.There are various ways to resolve depending upon the conditions like use existing, replace, keep both, use newer, use older, update in same path, update in new path and merge privileges.

What is the command manager used for?

The command manger is the one through which you can manage the applications, user accesses, security and databases of the microstrategy. The command manager allows us to save the text commands that can be executed as scripts. Thus it can help in automation of the entire management process.

What are the nulls on microstrategy report and how to mask them.

1)If in this question we want to deal with null in MSTR report than we have some display property in report data option which we can change according to the replacement of null values.

DATA>>REPORT DATA OPTION>>DISPLAY>>NULL VALUES

2)if we want to deal with sqlgeration of report than there is an option of VLDB property according to you requirment you can deal with sql query of report

Servers in MSTR

I-server: MicroStrategy Intelligent server provides jobs management and analytical processing for all MicroStrategy applications. This acts as a central component connecting the metadata, warehouse, desktop, Web server and Narrow cast Server. Few or main features:  Reports Services, OLAP Services, Data Mining, Multi Source connection, Caching, Clustering. Latest version supports installing I-server (different packages) on Windows, Sun Solaris, IBM AIX, HP-UX, Linux. Contact MicroStrategy for more information.

Web Server: MicroStrategy web server responds to the requests from browsers. Web server interacts with the I-server to extract the necessary information. Can be installed on most of the major web servers and supports most popular browsers. Contact MicroStrategy for certified products.

Narrow cast Server: Narrowcast sever delivers personalized business insight to emails, cell phones, pagers, file servers and print servers extending the reach of Business Intelligence applications. It offers a comprehensive solution for information delivery integrating a subscription portal with a delivery engine.

Roles in MSTR

·         Administrator: By default, the role/person will have full access to the environment. In other words this role has full access to all the type of objects mentioned above.

·         Architect: By default, access to configuration objects is restricted.

·         Developer: By default, no access to configuration objects, use access to schema objects and full access to public objects.

What are Passthrough Functions?
Pass through functions are used to utilize various special functions that specific to databases.Some of the passthrough functions available are Applysimple and Applycomparision.

What is the difference between warehouse and metadata partition mapping in MicroStrategyDesktop

Warehouse Partition Mapping:

Warehouse Partition Mapping tables are used for performance reason.

For example, a fact table in the data warehouse may have two columns: Sales and Years. If a report is run with Sales for the Year = 1999, the query engine will need to search through the entire table for all the years, including 1999, to return the data.

To improve efficiency, Partition Base Tables (PBT) can be created to have Sales for particular years. Assuming that there are 10 years worth of data in the database, 10 different partition base tables need to be created:

- PBT1: Sales for 1991 (Year=1991, Sales=$)
- PBT2: Sales for 1992 (Year=1992, Sales=$)
...
- PBT10: Sales for 2000

A Warehouse Partition Mapping Table (PMT) will then need to be created and will have:

Year	PBTName
1991	PBT1
1992	PBT2
...
2000	PBT10

The above PMT is going to tell the engine which table to grab the data from for a particular year. This means that when the report is run for Sales for 1997, then the query engine will first go to the Partition Mapping Table and then find the correct PBT corresponding to the year 1997.

Metadata Partition Mapping:

Metadata Partition Mapping Tables map the attribute elements to its corresponding PBT and performs the same function as the PMT.

To create a Metadata partitioning, follow the steps below:

1.     Go to Schema Objects > Partition, in MicroStrategy Desktop 8.x.

2.     Right-click and select new > Partition.

3.     Select the PBT. (i.e., PBT1)

4.     A data slice can be defined. The data slice will be the attribute (i.e., Year) to join from this metadata PMT to the PBT.

5.     Save and close.

By doing this, the equivalent of a PMT in the warehouse has been created, but in the metadata. In theory, both the warehouse and metadata partition mapping tables are accomplishing the same task