Life of a session.

[Eric Porter]

Problem :

I have a Web Server which is session enabled. I have a method within that
server which if I call it repeatedly, it seems to forget the session every
six re-tries, and all the data therein. Is there, perhaps, a time-out
setting somewhere (one of the myriad) that I may have missed (although I
have run this sometimes, gone for a cup of tea, and return, done a re-run
and it has remembered the session data).

I have noted that when the browser is in the mood for remembering session
data, it response almost instantaneously to the re-try button, when it is in
the mood for forgetting session data, it takes up to half a minute to
respond.

Please help.
--- code fragment from the web service class constructor, intialising the
session values. ---

if (this.Session["SessionValue"] == null) {
this.Session["SessionValue"] = "InitialValue";
}
if (this.Session["RefCount"] == null) {
this.Session["RefCount"] = 0;
}
if (this.Session["Timing"] == null) {
this.Session["Timing"] = DateTime.Now.ToString();
}

--- the web method called repeatedly to increment the RefCount, and dump the
other values. ---

[WebMethod(true)]
public string Environment() {

string rv;
int i = 0;

try {
i = (int) this.Session["RefCount"];
i++;
this.Session["RefCount"] = i;

rv = "";
StringBuilder sb = new StringBuilder();
foreach (string indexer in this.Session) {
sb.AppendFormat("{0} = {1}\n", indexer,
this.Session[indexer].ToString());
}
sb.AppendFormat("Session ID = {0}", this.Session.SessionID);
rv = sb.ToString();

} catch (Exception e) {
throw new SoapException("Environment failed : " + e.ToString(),
SoapException.ClientFaultCode);
}
return rv;

}

[Richard Thombs]

The session data will get flushed any time the ASP worker thread is
restarted. Check your IIS settings to see how often that is. I'm not sure
what the defaults are, but you can specify triggers based on elapsed
time, or a certain number of requests, or a certain amount of memory
usage.

Maybe your app is hitting one of those thresholds and causing ASP.NET to
recycle the worker thread.

Cheers,

Richard.

[Eric Porter]

Thanks for the pointer, Richard.

Here's what I've done :

In web.config, I have added a <processModel> section and set all things that
can be set to "Infinite" to "Infinte", and doubled all the times that don't
allow "Infinite", with the exception of responseDeadlockInterval. I have
also increase memoryLimit to 95%.

In IIS (The specific Web site settings)
Virtual Directory->Application Settings Configuration->Options->Session
Timeout = 20 mins
Virtual Directory->Application Settings Configuration->Options->ASP Script
timeout = 90 secs

In IIS (Default Web Site settings)
Web site->Connection Timeout = 900 seconds

But still the session persistence is hit-and-miss (when running in the
debugger, it's definitely more miss than hit), so after a random number of
method calls from the client, the session is restarted, and all previous
session values are lost.

Is there any other session setting that might help?
"Richard Thombs" <ri************@compositedata.com> wrote in message
news:pa****************************@compositedata. com...

The session data will get flushed any time the ASP worker thread is
restarted. Check your IIS settings to see how often that is. I'm not sure
what the defaults are, but you can specify triggers based on elapsed
time, or a certain number of requests, or a certain amount of memory
usage.

Maybe your app is hitting one of those thresholds and causing ASP.NET to
recycle the worker thread.

Cheers,

Richard.

[Richard Thombs]

Eric,

Sounds like you are running on IIS 5? I'm sorry, I think most of the
settings I was describing were for IIS 6. It seems to me that you have
changed everything that could be causing the session to expire.

Does the Session ID you are checking in your code change when the session
is wiped out?

Is there anything special about the the device is connecting to the
server? I'm not sure if session cookies are based on the machine's source
IP address - just thinking that perhaps the Pocket PC's IP address is
sometimes changing and that is causing the web server to think it's
another client and therefore starts a new session.

Richard.

On Thu, 08 Jul 2004 15:52:29 +0100, Eric Porter wrote:

Thanks for the pointer, Richard.

Here's what I've done :

In web.config, I have added a <processModel> section and set all things that
can be set to "Infinite" to "Infinte", and doubled all the times that don't
allow "Infinite", with the exception of responseDeadlockInterval. I have
also increase memoryLimit to 95%.

In IIS (The specific Web site settings)
Virtual Directory->Application Settings Configuration->Options->Session
Timeout = 20 mins
Virtual Directory->Application Settings Configuration->Options->ASP Script
timeout = 90 secs

In IIS (Default Web Site settings)
Web site->Connection Timeout = 900 seconds

But still the session persistence is hit-and-miss (when running in the
debugger, it's definitely more miss than hit), so after a random number of
method calls from the client, the session is restarted, and all previous
session values are lost.

[Eric Porter]

I am indeed running IIS V5.1.

The intersting thing about all this is that the SessionID remains the same,
only the Session[...] values disappear.

The only out-of-the-ordinary thing I can think of in my scenario is that the
Web Service I'm writing resides on a trusted network drive, with an IIS
virtual directory pointing at it (a technique I favour, because my C-drive
is not backed-up, but the network drive is). Could this be having an
adverse affect?

The next thing I was going to try, in an attempt to increase reliability of
my sessions, was to move the Web Service to my local machine.

Eric
"Richard Thombs" <ri************@compositedata.com> wrote in message
news:pa****************************@compositedata. com...

Eric,

Sounds like you are running on IIS 5? I'm sorry, I think most of the
settings I was describing were for IIS 6. It seems to me that you have
changed everything that could be causing the session to expire.

Does the Session ID you are checking in your code change when the session
is wiped out?

Is there anything special about the the device is connecting to the
server? I'm not sure if session cookies are based on the machine's source
IP address - just thinking that perhaps the Pocket PC's IP address is
sometimes changing and that is causing the web server to think it's
another client and therefore starts a new session.

Richard.

On Thu, 08 Jul 2004 15:52:29 +0100, Eric Porter wrote:

Thanks for the pointer, Richard.

Here's what I've done :

In web.config, I have added a <processModel> section and set all things that can be set to "Infinite" to "Infinte", and doubled all the times that don't allow "Infinite", with the exception of responseDeadlockInterval. I have also increase memoryLimit to 95%.

In IIS (The specific Web site settings)
Virtual Directory->Application Settings Configuration->Options->Session
Timeout = 20 mins
Virtual Directory->Application Settings Configuration->Options->ASP Script timeout = 90 secs

In IIS (Default Web Site settings)
Web site->Connection Timeout = 900 seconds

But still the session persistence is hit-and-miss (when running in the
debugger, it's definitely more miss than hit), so after a random number of method calls from the client, the session is restarted, and all previous
session values are lost.