SP2010 - Search results return exact same file more than once

Question

I have two WFEs in my environment running SP2010 and FAST Search Server 2010 on a Fast Content Service SSA. There are 9 site collections that are covered in the Content Source of that SSA. I have a file called "uniqueFile.txt" and it's part of the Site Assets of each site collection.

When I run a search for "uniqueFile.txt" it shows 17 results with 16 duplicates. Half of these duplicates are because this same file exists at different locations, however the other half of the results return are pointing to the exact same file twice (Same URL, same doc id.. etc).

I have gone through the crawl logs and these files have been crawled multiple times and each time it has the same Crawl ID.

What troubleshooting steps can you recommend?

Answer 1

The overall fix was to turn off Case Sensitive Crawling:

SharePoint Powershell:

$ssa = Get-SPEnterpriseSearchServiceApplication "FAST Content Service App"
$ssa.GetProperty("CaseSensitiveCrawling")

This should return False.

$ssa.SetProperty("CaseSensitiveCrawling",0)
$ssa.Update()
$ssa.GetProperty("CaseSensitiveCrawling")

This should return True.

Perform an index reset, following the instructions for clearing on the FAST Server also.

Answer 2

When you do an index reset with FAST in central admin you also have to clear the content collection using powershell from one of the FAST servers. This ensures the crawl database and index are in sync.