Chris May

We are getting a few errors in the IIS logs here and there. Some are no big deal, others should probably be looked into.

This page from MS ( and this one too I guess) shows basically what they all represent. The ones we are seeing are:

Connection_Abandoned_By_AppPool
A worker process from the application pool that quit unexpectedly or orphaned a pending request by closing its handle.
I'm not sure if this means "quit unexpectedly" like an exception was thrown, and handled, or if it means an unhandled exception was thrown, or the web.config was updated and the wp recycled. I guess it shouldn't be that last one actually because it is supposed to spawn a new wp and wait to kill the old one until it has completed all its requests, or varios criteria are met (like a request is in the queue for a long time, indicating a real problem anyway).

Connection_Dropped
Reserved. Not currently used.
Ha, looks like they haven't updated this doc recently. I still can't find any real info about this, but when looking through the logs it looks like these errors occurr either on pages that are known to have experienced timeouts of one kind or another (SQL timeout, or reportserver timeout), or page requests that happen very close to the a know timeout page. So maybe some page fails when trying to generate a billion page PDF report, and there are 4 more Connection_Dropped errors for "normal" pages right after that. Maybe those 4 were queued up by the thread that died?