topic Re: Calculated Dimension in QlikView

Calculated Dimension

brindlogcool — Fri, 05 Apr 2013 16:18:23 GMT

Hi,

Performance impact of using the calculated dimension. As per my understanding the calculated dimension will be executed for each row.Cost may vary based on the below scenarios

1. With if else condition--- It can be date comparision, Checking NULL values or Blank values.

2. Concatenation of strings - Without the if else conditions can be Splitting the strings or concatenation.

3. Having combined both point 1 and point 2.

Adding to the above points it can have the expressions with if else condition which will have performance impact. Also table has more than one calculated dimension .

I would like to know how the cost can be measured for calculated dimension. I understand that there are various factors needs to be included like system RAM,Data Size etc.

Re: Calculated Dimension

Anonymous — Sun, 07 Apr 2013 10:17:47 GMT

I cannot answer your question per se. But I have also been thinking about the potential performance inpact of calculated dimensions.

The scenario I have is needing to decide which of the 3 options below to choose:

a) Use a calculated dimension in a pivot table with its potential performance inpact

b) Use some ugly and inefficient sql in the QV script that extracts the data from the Oracle database

c) Use simple extract Oracle sql, and then some ugly and inefficient QV scripting to transform the data

I am hoping to test & compare these 3 scenarios next week.

In the meantime if anybody is able to share their knowldge and experience in this area, then that would be great.

Best Regards, Bill