What did you learn this week? w/o 16/3/20

Hi everyone!

Excited to see what you’ve been up to this week. Ready? What was ONE thing you learned or built this week that made your application(s) better?

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I overhauled this help document:


I learnt about LIST, thanks to Steve.


My learning: Thumb rule checklist for app performance.

While I did have an awareness on inefficiency of certain functions like SELECT() , in the post referred above, @Steve and @praveen have excellently elaborated the concept. I will have that post as reference post on app performance.

My thumb rule checklist learning from this post on performance.

  1. Any single factor may or may not contribute to performance degradation. Performance degradation may be combination of several factors mentioned below

  2. Use of multirow expressions- SELECT(), FILTER(), LOOKUP(),MAXROW(),MINROW() in virtual columns or in format rule expressions.Inefficient format rules impact display/rendering time

  3. More tables, more rows of data in the app. A) N tables, assume N/3 seconds of baseline latency B) Find largest table in terms of cells (rows * columns) and add 1 second for every 5000 cells

  1. Filtering conditions -
    Equality (=), IN(), and AND() of these are efficient. Inequality(<>) and OR() functions are inefficient
  2. Certain inherent latency is introduced by cloud provider as well. This latency is not necessarily related to data size.
  3. REF_ROWS VCs auto created by the app editor are not inefficient.
  4. In general, multi level SELECT() statements (A SELECT() in another SELECT() ) are a no-no.

I’ve learned that AppSheet blog “Feature Friday” is a very good reference for me, in addition to the “What’s New” and “Tips & Trick” Section of this Community.


This is late, but I learned about the IN() last week, really makes a lot of things easier for me.