sp_BlitzIndex finding “Unknown” index

Question

I am going through cleaning up one of our databases, and after deleting an unused index and adding a primary key to the ARPayments table, sp_BlitzIndex is now reporting an index dbo.ARPayment.Unknown (0). I have refreshed my indexes and there is definitely no sign of any such index.

Here is the message it shows in the output from running sp_BlitzIndex 'db_name', @Mode=4:

Should this table be a heap? dbo.ARPayment.Unknown (0)

Answer 1

sp_BlitzIndex will list Unknown for the index name when the table is a heap. It's not saying you have an index named Unknown. The primary key that you added was added as non-clustered, and you don't have a clustered index on the table. A heap is a table without a clustered index.

If you don't want your table to be a heap, you could drop the PK and recreate it as a clustered PK.