The application pool for this site was getting disabled quite frequently and we found quite a few entries like the following in the event log: Event Type: Error Event Source: W3SVC Event Category: None Event ID: 1002 Date: 19/11/2008 Time: 15:20:23 User: N/A Computer: <computername> Description: Application pool ‘DefaultAppPool’ is being automatically disabled due to a series of failures in the process(es) serving that application pool In this case the customer already had some debugging skills so when he called CSS he already had a few dumps available to analyze; they were some process shutdown dumps (taken on Kernel32!TerminateProcess), strangely we had no second chance dumps (maybe because of one of these reasons?) but they’ve been a good point to start from anyway. First, let’s have a look at the exceptions: 0:000> !dumpheap -type Exception -stat [...]Statistics: MT Count TotalSize Class Name79333ed4 1 12 System.Text.DecoderExceptionFallback79333e90 1 12 System.Text.EncoderExceptionFallback79330d44 1 72 System.ExecutionEngineException79330cb4 1 72 System.StackOverflowException79330c24 1 72 System.OutOfMemoryException7931ffd4 1 72 System.NullReferenceException6610c7fc 1 84 System.Web.HttpUnhandledException79330dd4 2 144 System.Threading.ThreadAbortException79318afc 2 144 System.InvalidOperationException7931740c 5 160 System.UnhandledExceptionEventHandlerTotal 16 objects Remember, a few special exceptions are loaded when the AppDomain is first created (see here) so let’s try to see if there is still something significant…
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Driver’s SQLAllocHandle on SQL_HANDLE_DBC failed
Another weird one I got this afternoon. A colleague from the Sql team asked my help about what looked an authentication problem is customer’s web application, while trying to connect to a Lotus Notes database: in short, the customer was developing his application with Visual Studio 2005 and was testing it with Cassini, and everything looked fine, but as you can guess the problem arose when he deployed the site on his test IIS. They got the error [IM005] Driver’s SQLAllocHandle on SQL_HANDLE_DBC failed. The first thought was about a permission problem, since as you may know one of the main differences between IIS and Cassini is that the latter is essentially a process which runs in the context of the account logged on the machine, while IIS is a service which runs under different accounts but with lower privileges. Ok then, to verify this hypotheses we made a quick change to the <processModel> section to have the worker process running under the customer’s account instead of the default ASPNET (he was testing on his local IIS 5.1 on XP). Well… same problem. So that could not be a security problem, ASP.NET was running as an administrator… ? The error…