What columns count as lookup column concerning the "List View Lookup threshold"

Question

I got the following entry in my SharePoint 2010 log file: "Some lookup fields were omitted from the query results because the list exceeds the lookup column threshold."

I checked the setting (Central Administration, select WebApplication, Resource Throttling) and saw a "List View Lookup threshold" of 8. But when i check my list i can only see 6 Lookup Columns.

• 5 managed metadata columns
• 1 normal lookup column to another list

So my question is: what type of columns do count as lookup columns? Do "Person or Group" columns count? How about "Created by" and "Modified by"?

Thanks for your help!

regards
tschuege

Answer 1

Not exactly an answer, but it may help you figure it out: The setting says:

"List View Lookup Threshold
Specify the maximum number of Lookup, Person/Group, or workflow status fields that a database query can involve at one time. "

In the API, both Managed Metadata and Person/Group fields inherit from lookup fields; it's also possible that you have some other field types that inherit from lookup.

That being said, it can't possibly be counting everything of one of those types, as there are many "behind the scenes" fields that use them. It also definitely isn't counting dependent lookups as distinct columns for the count, I have one list with 8 of those defined and some other managed metadata etc.

Answer 2

SharePoint Lookup columns are columns located in a SharePoint list which get their values from another SharePoint list.

Example:

List1 -> ID                    List2 -> Countries
      -> Name
      -> Location 

In this example we have two lists with their fields. If we want to create the Location field as a lookup we create a new column in SharePoint with a type Lookup and point it to the Countries column in List2. So the Location column will be like a drop down menu containing all the items located in List2 in the Countries column.

So the Lookup columns get their values from other columns.

You can know which columns are Lookup or not by checking their type. You can go to your SharePoint library and view the Library Settings where you can see the library columns. If the column type is Lookup, so it is a Lookup column.

For example the "Created by" and "Modified by" columns are of type Person or Group and not Lookup.

Concerning the "List View Lookup threshold" the managed metadata columns, Lookup, Person/Group and workflow status columns are counted.