Recently, I was getting this error in one of our Sitecore 7.5 instances:
ERROR Failed processing expired items. Session type: d027da82-f6a4-4275-bb09-8bd3732d828e
Transaction (Process ID 127) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
Wednesday, 15 April 2015
This post documents Sitecore's ExcludeRobots pipeline and is part of a series providing information on all the pipelines and processors in involved in a Sitecore 8 request. It's not a line by line account, but all the key logic is described.