Was browsing some Qv blogs tonight and stumble upon Rob Wunderlich post about color coding Y/N expressions using visual cues and dual() (http://qlikviewnotes.blogspot.se/2014/04/performance-tip-using-dual-and-chart.html). I thought that visual cues was quite slow compare to using expression background so i thought that i should do some performance testing.
I created an app with around 4 millions rows and a straight table with 2 expressions, one simple sum() and one with a complex formula returning either Y or N.
The results
- No color coding – calctime of 22.963
- dual and visual cue – calctime of 23.213
- same exp in background color expression – calctime of 28.923
- reference using [expression label] – calctime of 29.609
- reference using column(X) – calctime of 29.703
My conclusions
- For Y/N and similar expressions – use dual() and visual cues
- For more complex ones (returning a lot of different values) – doesn’t really matter which one to use
yaqvblog 