Incremental/Continuous crawl and case sensitivity - Duplicate items

Question

I just stumbled upon an interesting behavior:

1. Have a document set:
   • Title: My Special Document Set
2. Perform a crawl (continuous / incremental crawl)
   • Search returns 1 result.
3. Rename the document set with different casing: "my special docuMENT SET"
4. Perform a continuous / incremental crawl
   • Search returns 2 results. One for each case (my special... & My Special...)
   • The DocId managed property is different for both search results
   • The Duplicate Rows are 0 or in other words: Total Rows: 2, Total Rows including Duplicates: 2, so trimduplicates=true does not help, still 2 results.
5. When I now perform a full crawl, the duplicate entry is removed.

It seems as continuous and incremental crawl do not take care of casing/renames of folders/FileLeafRef and create a duplicate entry for when only the casing of an item is changed. Besides running a full crawl, is there anything else I could do about this?

We're currently evaluating creating an event receiver to trigger CrawlLog.RecrawlDocument on renames but that seems kind of non-standard and weird. The SPListItem.UniqueItemIdis the same for the item so we could actually filter the result set. - weird that duplicate detection doesn't kick in

Answer 1

This is a SharePoint Bug. It seems to be fixed in the October 2014 CU, I couldn't find any details in any KB article though.

I installed the May 2015 CU on a SharePoint 2013 SP1 patched server and the problem is gone.