Strange DB connection count increase

Chris Wellings cwellings at
Thu Dec 19 03:42:39 EST 2013


I'm trying to investigate an issue we saw the other day when our Shibboleth session database suddenly had a large amount of database connections . Usually we see about 10-30 connections in a 5 minute period but this increased to over 700 connections in a five minute period (for about an hour we had an average of  100 connections per minute.) Any ideas what this was? We think the problem was solved by deleting all the session data from the tables. The logs don't really show anything strange before the amount of connections took us over the threshold of allowed connections except:

ERROR Shibboleth.LogoutInitiator.Local [72]: error accessing current session: ODBC StorageService failed to set transaction isolation level.

And then a few seconds later:

WARN Shibboleth.SessionCache [71]: unsuccessful read of session (ID: _SessionId), caches out of sync?

(We had five servers in the non-sticky load balancer and we know the above problem wasn't due to high load - requests per second wasn't any higher than normal (checked against our code and IIS logs).)

I realise this isn't much information to go from but I was hoping that someone who knows the code a lot better might be able to shed some light on the issue we saw?

Many thanks,

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