Is ShowColumns() subject to delegation with a sharepoint source?

[martinav]

I have a rather complex sharepoint list for which I only want to pull a few columns from.  The list is over 2,000 rows.  This statement works fine:

ForAll(Distinct(UpdatePartNumbers,MD_PartNumber).Result,Collect(UpdatedFromMDL2,LookUp(Master_Drawing_List,MD_PartNumber=Result))

However, this statement works, but there are missing items.  There is NO delegation warning, howerver:

ForAll(Distinct(UpdatePartNumbers,MD_PartNumber).Result,Collect(UpdatedFromMDL,LookUp(AddColumns(ShowColumns(Master_Drawing_List,"ID","MD_PartNumber","MD_Project","MD_LatestRevNumber","MD_DrawingRevDate","MD_EngrgRelDate","Title","MD_PDM_Link","MD_LinkToDrawing","MD_IsActive","MD_Data_Flagged","MD_Latest_SW_DocumentID"),"LastCost",Blank(), "OnHand",Blank(), "Available", Blank(), "Location_Acct", Blank(), "Discontinued_Acct", Blank(),"Acct_Bom", Blank())

The only difference is the ShowColumns.  I would like to avoid pulling in all of the extra data, and then the time it takes to parse it down to the columns I want after the fact in a subsequent Collect() statement.

[RandyHayes · Accepted solution]

@martinav 

ShowColumns cannot be delegated.  (nor, AddColumns, RemoveColumns, or DropColumns)

I believe (never saw or really took note) that the magical blue squigglies only come out on operators, not on functions. So you would not see that showing a warning.

Hope that clears it up some.

[martinav]

@RandyHayes ,

Figures...  More wasted hours...

So, I have to collect ALL rows, then parse it down in another collection.  

[RandyHayes]

@martinav 

Pretty much that if you are dealing with a delegation issue and there is no way to delegate the query elsewhere (i.e. a View in SQL), then you are going to have to suck down all the records and do your own filtering or other actions.

Since your source is SharePoint, there's not much more you can do to resolve it...unless you try to connect to Azure Functions and delegate to them - but, I hear the can opener running...a new can of worms is now open.

[martinav]

Yea, I wont be messing with that.  Generally, the number of records returned is not going to be more than a few.  I can deal with the excess for this case.  Thanks for your replies.