Tableau Interview Questions and Answers

Hello Guys

Here I am sharing Tableau very tough and unknown questions and answers. Please let me know if you find any answer which looks not suitable.

1.     How can u improve performance of tableau server?

Ans:

·      Avoid Quick filter as possible. If required, we can use context filter for better performance.

·      Better web browser.

·      Use extracts instead of live connection.

·      Use cache mechanism

·      Use incremental extractions

·      Avoid the high resolutions images

·      Adjust the count of application server and vizql server for hitting cache.

·      Set both at 1x to 2x times the number of processing cores present on the server

·      User should not access the dashboard while loading the data

2.     If my dashboard is taking long time to render on server what could be the reason?

Ans:

·      Use Window_sum() instead of totals(). It is slow while extracting.

·      Avoid quick filters in dashboards

·      Source data bins give better performance than tableau bins.

·      Use sql query instead of data blending if you are using RDBMS.

·      Use less than 5 views in dashboard.

·      Optimizing data extracts

3.     When 10 worksheets are combined and made a complete dashboard if one worksheet is updated. Is it necessary to publish only changed worksheet or entire dashboard?

Ans : Only changed worksheet.

4.     Which databases gives best performance when connected live?

Ans : Expected answer from you. Please suggest us. Analytical databases are good for tableau. Means OLAP.

Exact Ans: Native databases

5.     What if customer is asking for data refreshed at minute level? What would you suggest to the customer?

Ans : It is performance degrade. Using Java Script APIs we do that.

6.     How to switch views in dashboard?

Ans : Using parameters

http://kb.tableau.com/articles/knowledgebase/creating-sheet-selector-for-dashboard

7.     What complex dashboard you designed so far?

Ans : Displaying bar charts on tool tip pop up, switching views dynamically, LODs

http://kb.tableau.com/articles/knowledgebase/barsintooltips

8.     What are challenges faced when working with huge volumes of data?

Ans :

1.     View running slow.

2.     Data extraction.

3.     Alignment issue with data.

4.     Testing data

9.     How did you handle working with huge volumes of data and how about performance tuning?

Ans:

1.     Optimize the data model.

2.     Use statistics

3.     Tune your indexes

4.     Partition the data in database level.

10.  Tells us about conditional formatting in tableau?

Ans: Using KPI, color marks and calculation field

11.  How many dashboards you created so far?

Ans: Nearly 50 dashboards

12.  Have you ever worked on creating custom maps?

Ans: No. If yes using mapbox

http://www.theinformationlab.co.uk/2014/01/21/information-lab-brings-new-mapping-tableau/

https://www.interworks.com/blog/zgorman/2015/05/11/bringing-custom-map-tableau-10-minutes-or-less

13.  In backend database you have day level data how can you change it to week/month/year level in tableau?

Ans:

If we need to change columns from date to other format

1.     DATETRUNC for Accurate dates.

2.     DATEPART

14.  If my Informatica job is done and I want schedule tableau report. How can we do it?

Ans:

tabcmd runschedule or tabcmd refresh extracts will do the job. We need to configure in informatica level. It will start once load is completed.

Ref: https://community.tableau.com/message/426359

15.  How do you go about migrating workbook from reporting to QA or Prod environments or any different environments etc?

Ans:

Development is happened in desktop. We can directly posted to QA for testing and prod for live. Development server is not required for this.

https://community.tableau.com/thread/193711

16.  Have you ever worked with director level personnel in your projects?

Ans: Yes.

17.  How do you train power users?

Ans:

Below are explained in high level. But not technical. We should use functional terminology.

·      Purpose of dashboard.

·      Filters

·      Actions

·      Drill down

·      Conditional formatting

18.  What is level of detail? Scenario in which level of detail is used?

Ans:  LOD is good concept for different data between AVG or total and details level.

·      Fixed

·      Include.

·      Exclude

19.  Example of a stored procedure used in SQL Server?

Ans:

http://onlinehelp.tableau.com/current/pro/online/windows/en-us/help.html#connect_basic_stored_procedures.html%3FTocPath%3DCreate%2520and%2520Manage%2520Data%2520Sources%7C_____6

20.  A workbook gets data from 2 different sources, can you create parameter so that it can be applicable on both data sources?

Ans:

 http://kb.tableau.com/articles/knowledgebase/filter-data-sourcesHow do you create a dynamic parameter on a date field called " till yesterday" to retrieve the yesterday’s data whenever needed?

Ans:

21.  Have you worked on groups and sets? Which scenarios are these applicable?

Ans : Yes.

Groups:

·      We can see the group of data in single row.

·      If we want to calculate and see the data for group for values

Sets:

·      Sets are custom fields that define a subset of data based on some conditions.

·      For conditions

·      Top N

·      Combine two set of data.

22.  If you have a dimension called AGE with values ( 10,20,30,40,50). If i create a group called less than 30 and another group called less than 20 with in this? If yes how?

Ans: We can create sup groups

23.  What are the real time thumb rules to follow in developing Tableau dashboards?

Ans:

·      Using the best types of charts or graphs that are right for your data

·      How to blend data from multiple sources for a holistic view

·      Max three view gives best performance in dashboard which is suggested by tableau

·      Choosing critical dashboard metrics that reflect organizational objectives

24.  We have a dashboard can we do a quick assessment of performance in real time? How?

Ans:

·      Checking with Microsoft access or excel dashboard and then write logic and then compare time count.

·      Decide where the performance issue.

·      Tune the tool or query or view based 2nd step.

·      Record live performance under help menu

25.  In which case LOOK UP function in tableau used?

Ans: Lookup function is for YOY calculation. We can calculate prior year data.

http://breaking-bi.blogspot.in/2013/04/using-lookup-function-in-tableau.html

26.  Have you done any Polygrams?

Ans: No.

If Yes

http://kb.tableau.com/articles/knowledgebase/polygon-shaded-maps

27.  What type of Documentation did you do and tool used?

Ans: NA

28.  With extract from excel how to manage data on source server?

Ans:

29.  Most difficult or challenging part faced in tableau?

Ans: Dealing with big data

30.  How do you increase the performance of filters?

Ans:  Context filter gives better performance.

31.  How can you improve the performance while working with large data?

Ans: It is duplicate question for earlier question.

32.  State a real time problem faced and how did solve it?

Ans: Filtering in LODs Recent issue

33.  Difficulties faced as a data analyst.

Ans: Data validation.

34.  What is the maximum number of files you have worked with?

Ans:

35.  Problems faced while extracting data from excel?

Ans: None

36.  How do you implement tableau public?

Ans: I explain it.

37.  What is necessary for maintaining a secure data?

Ans: Tableau Server, and Through Java Script API

38.  Difficulties faced with large data?

Ans : missing data

39.  How to test the dashboards or reports in tableau Is there any special procedure?

Ans :   Use interworks performance analyzer

https://www.interworks.com/solutions/business-intelligence/data-visualization/performance-analyzer

http://kinesis-ci.com/

40.  How many servers have you connected and run on Tableau, How many servers did you have in your company.

Ans:  1 server

41.  How to do complete automation of excel reports to tableau reports?

Ans:  given in above  (UNC)

42.  Assume Referential Integrity?

Ans.

When you are working with multiple tables in a data source, and you have joined multiple tables, you can improve query performance by selecting the option to Assume Referential Integrity from the Data menu. When this option is selected, Tableau will include a joined table in the query only if it is specifically referenced by fields in the view. Referential integrity exists when any value you specify from a column in one table is assured to exist as a value for a column in any joined table