Session State lost in asp.net - solution explained.

[Brian Schloz]

Hello,

I just thought I'd share my particular situation regarding session
state periodically being "lost" in my asp.net app. I read with
interest all of the posts regarding lost session state (virus scanner,
modified assemblies/configs, etc.). The suggested solution of using a
'State Server' or 'SQL State Server' was not attractive to me given
the drawbacks: performance, objects must be serializable, no more
Session_End.

Perhaps the most helpful advice I ran across was to use Performance
Monitor (perfmon) to monitor various counters of the .NET processes.
So, I setup perfmon and added all sorts of counters. The two counters
that led to my solution were: Application Restarts and Compilations
Total. After a period of monitoring I noticed that 'Compilations
Total' would hit a threshold and kick off an Application Restart
(which in turn caused anyone in my app to lose their session state).
After careful review of the machine.config file, I found the culprit:

numRecompilesBeforeAppRestart="max number of recompilations before
appdomain is cycled" // Default: 15 recomplations

If I increase this number to say "9999", I never run into the lost
session state. However, I am concerned about this solution given by
the fact that the default value is so low (15 - why????). Unless
someone can point out the reason this may be a bad fix, I will happily
continue forward (my users are happy now too).

Brian Schloz
Lead Software Engineer
JHOB Technologies, LLC

 

[Cowboy \(Gregory A. Beamer\)]

The downside is you have to manually restart the app every once in awhile to
clear out memory. There is a known bug in 1.0 (see KB 319947).

In most cases, you should not have to dynamically recompile resources very
often. If your app recompiles on a regular basis, you have another problem:
perhaps a design problem, perhaps a resource problem.

One possibility, for example, is an app that writes values to web.config,
which will force a dynamic recompile. If this case, the correct design would
be to only store constants in the .config and other app values in either a
static object or some other form of cache.