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From Igor Cicimov <icici...@gmail.com>
Subject Re: two questions about the session timeout in tomcat
Date Mon, 10 Oct 2011 08:18:24 GMT
Is there anything in the log files? Do you have enough threads in the thread
pool? I would also ask the DBA's to give me the list of the longest running
queries.
 On Oct 10, 2011 3:02 PM, "Bill Wang" <bw57899@gmail.com> wrote:

> Hi Chris, Pid & Geroge,
>
> Thanks to everyone who replied my mail. I try to answer your questions in
> one mail.
>
> 1. I access the admin interface by manager app. I'd like to have exist
> command to run and get the report easily, if there is no the command, I
> will
> think to use wget | crul.
>
> 2. The application with sessions under 60 normally has no issue. But when
> the session go up to 80 ~ 100, I start to get calls from the customer. It
> happens many times at random time. Sometime I have to restart it, without
> any changes, after restart, customer can continuous use it. This
> performance
> issue is very annoying.
>
> 3. From Chris explanation, looks to change the timeout to 30 minutes will
> be
> good idea, since I don't care of the end users to login the system
> more frequently,  I need more stable system.  The server has other heavy
> applications running, CPU load is always up to 10 ~ 20,  available physical
> memory is not too much (<10GB).
>
> 4.  We are doing the troubleshooting on this application recently and don't
> find too much can be done. Check with network and DBA team, they all report
> me there is no issue. Contacted with Developers who maintain the tomcat app
> codes, they said the code running in their testing environment is fine. I
> am
> planned to do some load testing,  but it is just in plan.
>
> 5. @ Pid:
>
> Can you explain me more detail on how to do with your suggestion, I am not
> developer, don't write codes, my role in this project is to setup the
> webserver, tomcat service and make it running and stable.
>
>
> *******************************************************************************************
> The session count per application can be read via a JMX connection and
> a request to the appropriate MBean.
>
> *******************************************************************************************
> 6. @ Geroge
>
> Sorry, I don't understand your question.  We DO have Oracle Database in the
> backend.
>
> *******************************************************************************************
> Are you storing objects on the session, in particular JDBC connections
> or result sets?
>
> *******************************************************************************************
>
> Regards
> Bill
> On Sat, Oct 8, 2011 at 1:23 AM, Christopher Schultz <
> chris@christopherschultz.net> wrote:
>
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Bill,
> >
> > On 10/6/2011 7:20 PM, Bill Wang wrote:
> > > Recently one of Tomcat application has performance issue, which get
> > > slow respond with high sessions.
> >
> > Can you give us some numbers? At what point do things slow down, and
> > by how much do they slow down?
> >
> > > One team member recommend me to adjust the  session timeout from 60
> > > minutes to 30 minutes.  I will do that, but before change it, I'd
> > > like to understand how the performance related with the expire
> > > session timeout.
> > >
> > > <session-timeout>60</session-timeout>
> >
> > I'm not sure performance will change at all when changing the session
> > timeout. Tomcat runs session-expiration tasks periodically, and the
> > performance of that has more to do with the number of total sessions
> > than the timeout itself.
> >
> > If you have lots of sessions that must timeout instead of being
> > explicitly invalidated (i.e. people close their browsers instead of
> > logging-out), then you will have a lot of wasted memory that may
> > prevent the garbage collector from working efficiently. It's best to
> > destroy sessions as soon as they are not needed, so short session
> > timeouts can help with that. On the other hand, you want to give users
> > a reasonable amount of time to get a cup of coffee, etc. without
> > forcing them to re-login every time.
> >
> > You'll have to determine what is an appropriate amount of time for
> > your users.
> >
> > There is another option: selectively extend the session timeout for
> > certain sessions, or for certain operations. If a user enters a flow
> > that is expected to take a long time or the consequences of having the
> > session time out are frustrating (i.e. you have to re-enter tons of
> > data), you can change the session timeout for that one session to be
> > longer than the default. When the flow is over, you can re-set it back
> > to the default. We do that for a number of tasks in our webapp, for
> > instance.
> >
> > > Second, currently I monitor the session count by login the admin
> > > interface,
> >
> > Do you mean using the "manager" app?
> >
> > > the manual way is not efficiency, can I run some commands to get
> > > the sessions number? With that I can set a cronjob and generate the
> > > session report easily.
> >
> > If you have the manager app deployed, you can use the text or XML
> > interfaces from the command-line instead of the HTML interface. Simple
> > use of wget, curl, etc. should allow you to do this kind of thing.
> >
> > - -chris
> > -----BEGIN PGP SIGNATURE-----
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> > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
> >
> > iEYEARECAAYFAk6PC2gACgkQ9CaO5/Lv0PBo3gCgvV7dAylXSz1vz3jRX2jmr1lE
> > E9kAoMKnHUgOC5MEx31lz121tXT1aV8J
> > =CGz3
> > -----END PGP SIGNATURE-----
> >
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>

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