Filter large SharePoint list (>2000 items) by value in nested table?

[Cayshin]

I have a large SharePoint list that we'll call Table1. In Table1 I have a Person/Group column (a nested table) that'll we'll call Table2.

In my app, on loading, I only want to collect the rows from Table1 where User().Email is found in Table2.

This is part of the formula I'm using: Filter(Table1, User().Email in Table2.Email). When I set a Gallery's items to that formula, nothing is found even though my email does exist in some places in the People/Group column.

PowerApps gives a Delegation Warning about In, but the PowerApps Delegation documentation says In is supported.

Is there a way to accomplish what I'm trying to do?

[RandyHayes]

@Cayshin 

The In operator is actually not delegable to SharePoint.  The documentation you mention discusses general delegable operators. However it does mention that each connector has its own specific set of operators that are delegable.  In the case of SharePoint, if you look at the connector documentation for delegation, you will see that In is not listed and thus will not be delegable.  I know, it's confusing!  I would rather they specify delegation in a whole different way so that it is crystal clear for people, but not at this time.

So this does not mean that you can't do what you need, you just need to go about it in a different way.  One way to to try and collect all of the records from Table1.  I find that to be excessive for these type of things, but it is an option.  

Another option is to utilize a ForAll function to return a table of what you want.

But, I am not clear how to proceed in your case because your formula is not very clear.  In your Filter(Table1, User().Email in Table2.Email) formula, this doesn't really make sense.  The Filter function has two parameters - the datasource table and the criteria.  Filter will go through each record in the table and apply the criteria to evaluate to true (include record in result) or false (exclude record from result).   In your case your criteria is to look up the current user email in Table2's Email column.  That will return true for each record of Table1.  So, the end result is, you're not going to get anything relating Table1 and Table2 together.

If I had to make a guess, you are really trying to find if the user in Table1 record is found in Table2 email column based on the current user.  And if that is the case, then you really don't need to do anything with Table2 because (in your post description) you have not established what the relationship is between Table1 and Table2.  You said you wanted records from Table1.  But what is the relation to Table2?

I hope this is helpful for you.

[Cayshin]

@RandyHayes 

Thanks for providing the correct delegation info.

I originally did collect the entire table, but, due to the table's size, it was slower than I'd like.

(Because of the 2000 limit I found this workaround: 
ClearCollect(LoopCount,FirstN([0, 2000, 4000, 6000],RoundUp(First(Sort(Table1, ID2,Descending)).ID2/2000,0)));
Clear(ListItems);
ForAll(LoopCount,Collect(ListItems,Filter(Table1,ID2 > Value)))
)

To clarify my issue, I guess it may be from my misunderstanding of how nested tables work?

I assumed that because Table1 contains a People/Group column (Column1), and Column1 itself contains a table (which I'm just calling Table2 for this post) for each record, then the Filter operator should have then been able to "dig down" through Table1 into Table2 to find the matching value.

Or perhaps my naming convention in the formula was confusing. Would it have been more accurate as Fitler(Table1, User().Email in Column1.Email)?

So in the case of my formula, the Datasource is Table1 and the criteria is matching a value in the Email column of the table residing in Column1.

I know how to reference nested tables, but I've never done it before as a part of a filter criteria.

[RandyHayes]

@Cayshin 

This is clearer.  So the bigger question now is about your Person column - does it allow multiple people to be selected or is it a single person column?

[Cayshin]

The People column allows multiple selections.

[RandyHayes · Accepted solution]

@Cayshin 

Ouch!! That is a challenge to delegate properly - in fact, you can't really delegate that criteria.

Here are the options:

1) Consider an alternate list to be an index to the first.  This is a pain for the data side of things but much faster from the app perspective. 

The concept is to write another record to a second list with the user email and the record ID in it whenever you set a user in the primary table, or have PowerAutomate do this when a record is added or changed.

You would then, from your app, be able to do a delegable filter criteria to the second list:

   Filter(recordList, Title=userEmail)

This would return a table of all the record ID's in the primary.

This works but has to be done just right to be accurate.

2) Go back to pulling it all into a collection, but consider the following changes to your formula to speed up a little:

Concurrent(
   Collect(List0, Filter(Table1, ID2 >0)),
   Collect(List1, Filter(Table1, ID2 >2000)),
   Collect(List2, Filter(Table1, ID2 >4000)),
   Collect(List3, Filter(Table1, ID2 >6000))
);
ClearCollect(ListItems, List0, List1, List2, List3)

Then you could perform the criteria against the collection.  This is much slower for the app.  Especially if you need to refresh.

[Cayshin]

@RandyHayes 

Thanks for all your help!

I was worried that was the case but was holding out hope. I'll implement your second suggestion for a faster collection process.

[takolota]

There is now a different SharePoint delegation workaround that doesn’t involve secondary lists or collections: https://powerusers.microsoft.com/t5/Community-App-Samples/Large-SP-List-Delegation-Workaround-App/td...

It uses a Power Automate & ParseJSON( ) set-up to delegate filters to SharePoint & to flow actions without many of the typical delegation limits placed on a direct SP connection in Power Apps.