SQL Delegation Issue on AddTable

[robinthakur]

I'm using a Query using AddColumns to join two table together:

SortByColumns(Filter(AddColumns('[dbo].[DailyChecks_Mlog]', "Description Of Maintenance Job", dc_mlog_desc, "Maintenance Location", dc_mlog_loc, "Date Entered", Text(dc_timestamp ,"[$-en-GB]dd.mm.yyyy"),"Home", LookUp('[dbo].[DailyChecks_Master]',dc_record_id=dc_master_id).dc_home_id),Home=SelectedHome.Intranet),"dc_timestamp",Descending)

It's stopping returning rows at 500 like it's hitting a delegation problem. However I've checked the documentation for delegation on SQL, and the functions I'm using are all delegable (from what I can understand) as the Filter is comparing ints and Lookup is delegable. Even if I pare it back to:

AddColumns('[dbo].[DailyChecks_Mlog]', "Description Of Maintenance Job", dc_mlog_desc, "Maintenance Location", dc_mlog_loc, "Date Entered", Text(dc_timestamp ,"[$-en-GB]dd.mm.yyyy"),"Home", LookUp('[dbo].[DailyChecks_Master]',dc_record_id=dc_master_id).dc_home_id

It stops at 500 items. What is the likely issue here and how can I work around it without lifting the item limit to 2000 as I don't want to do that. 

Thank you in advance

R

[yashag2255 · Accepted solution]

Hi @robinthakur 

This is because AddColumns expression is not delegable. Can you try to update your expression to:

SortByColumns(AddColumns(Filter('[dbo].[DailyChecks_Mlog]' ,LookUp('[dbo].[DailyChecks_Master]',dc_record_id=dc_master_id).dc_home_id = SelectedHome.Intranet ),"Description Of Maintenance Job", dc_mlog_desc, "Maintenance Location", dc_mlog_loc, "Date Entered", Text(dc_timestamp ,"[$-en-GB]dd.mm.yyyy"),"Home", LookUp('[dbo].[DailyChecks_Master]',dc_record_id=dc_master_id).dc_home_id),"dc_timestamp",Descending)

Hope this Helps!

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[gabibalaban · Accepted solution]

Hi @robinthakur ,

Try to define a view on SQL database to extract and arrange the data and then filter this by Home=SelectedHome.Intranet and also sort it.

[robinthakur]

Thank you both! I went the SQL route with views as that was actually very easy, but both approaches would work I believe. Crucially, it's easier to understand than the syntax of Addtables 🙂 I think it just threw me as there was no delegation warning, but I won't make that mistake again! Will replacing all direct read-only calls to tables with views speed up the app and is it in fact best practice? 

[robinthakur]

I did however notice one issue with this approach however. If I call the Refresh() command on the view after I've added an item, the view of items just disappears. and the gallery or table becomes empty. Is this a known issue with using views instead of direct SQL? 

[robinthakur]

Fixed the issue with the disappearing galleries. I was because my items query was driven using the view and a context variable which was getting reset. Storing this on a context variable and then using that worked.