Re: Inactive instance but no deaths and no logs

Simon

On Thursday, January 29, 2004, at 02:00 AM, Simon wrote:

>
> hi all, i'm having a troublesome deployment week !
>
> we have an app that is running with 8 instances configured. every now 
> and then (at least a couple of times per week) we get the odd instance 
> become completely unresponsive. the strange thing is that there is no 
> output in the logs, and monitor records no deaths. if i try and stop 
> the instance in monitor nothing happens, but i can delete it. however 
> if i then add a new instance and try and start it up monitor will 
> complain that it's allocated port is still in use.
>
> i'm a little puzzled as to how to debug this one, but what's more 
> annoying is that it is virtually impossible to pick up the error as 
> there is no indication in the logs that something is wrong, and 
> because the instance doesn't die monitor doesn't send me an email! we 
> only noticed it because a user reported the site being slow, which was 
> actually due to them being allocated the unresponsive instance upon 
> their first request and the adaptor waiting 30 seconds before shifting 
> them to another instance.

Sorry I don't have an answer, but I do have the same experience.  In my 
case we are only running one instance so I know when it's happened 
because the client rings me up to report non-response.  The app is used 
in-house with only half a dozen users, so we're not dealing with a 
wider audience.

If I set the unresponsive instance to "Refuse new sessions", all except 
one (or maybe more) of the sessions will expire within the timeout 
period, but one or more will never die. Presumably those sessions are 
"stuck", causing the original problem.

I have blamed my code, and worried about deadlocks, but investigations 
have not confirmed this. I've tidied up some code and it seems to 
happen less often, but I cannot conclusively say I've fixed it.

Denis