Data row limit affecting delegated results?

[Rob_CTL]

Hi,

I am looking for someone to save my sanity!  I am just testing a new app that when it goes live will be run against a large data set (SharePoint lists).  To make sure that delegation wouldn't be an issue I set the "Data Row Limit" to 1, theory being that if a function was subject to delegation it would now show up when testing against the smaller test data.  

Now the bit that is confusing me, after setting the Data Row Limit to 1 all my combo boxes started showing just 1 item, the first item in the list (putting the limit back to 500 all the items started showing again in the combo boxes).  The functions I am using for these Combo boxes are really basic ones like:

i.e. listname.column

I was under the assumption that this was delegable, maybe it's not or maybe there is something else going on here I am missing. 

Any thoughts/comments gratefully received.

Regards

Rob

[RandyHayes]

@Rob_CTL 

Record limit and Delegation are two different things.  Record limit determines the number of records that your app will be able to retrieve at one time.  Delegation refers to being able to delegate a query to the datasource and then have it return the results.  If the results are MORE that the Record Limit, you will only get the record limit amount of records returned - even from a delegable query.

I hope this is helpful for you.

[Pstork1]

One addition to @RandyHayes comments.  What makes this confusing for a lot of people is galleries.  Galleries will ignore the Data Row limits if the Items property is using delegable functions.  That's where the test of setting the data row limit to 1 comes from.  If you want to check whether the Items setting for a gallery is delegable just set the data row limit to 1.  If you get 2-100 records in the gallery then the formula is delegable.  If not then its not.  But in my experience that only works for galleries.

[Rob_CTL]

@RandyHayes thanks for the reply, at the moment I've only changed the data row limit, from the description in PA this limits the number of records where delegation isn't possible (see below).

So does this mean that the standard function I used above isn't delegable, thus the combobox is going to limited to showing 500 items? Of course that would be a very long scroll box, but I am using the search function within the combobox to speed up locating the desired item, maybe I need to use another function to get around the limit.

Cheers

Rob

[RandyHayes · Accepted solution]

@Rob_CTL 

I believe the working in that setting is misleading!

The only control that will sort of act that way is the Gallery.  However in your other controls, you will be limited to "record limit" number of records regardless of delegable or not.

If you're going to use the Search function, then yes, you will have delegation issues as it is not delegable.  If possible, you could look at the StartsWith function for the Filter.  If the search ability is the only requirement, then the only choice would be to bring in all of the records of the list into a table variable and then perform the search function on that variable.

[Rob_CTL]

Thanks @RandyHayes that explanation has reduced my headache 🙂  I do love PowerApps but it really does sometimes feel like it's one step forward and two back.

[RandyHayes]

@Rob_CTL 

It can feel like that sometimes.  

If you really want to blow your mind, wait until you discover that datasources refresh on demand automatically!!  Meaning, you don't have to issue a costly Refresh statement on a datasource...it will get new values in real-time!  But, that is off-topic, so I will leave that for another day 😋