Thanks Jon, I'll bear that in mind when we get to pooling, probably
sometime next year.
At this point it's a pretty standard client server app, running off a
Citrix server. There's no pooling since each client uses the app both
independently and sporadically.
Jonathan Lewis wrote:
> Is this a case where the application "closes the connection",
> but a background library is actually keeping a pool of
> connections open, and dynamically increasing it in
> response to the incoming load ? (i.e. typicaly web application
> scenario).
>
> If so, you may be experiencing the problem that occurs
> where the a real new connection needs a large chunk of
> contiguous memory from the shared pool and starts to flush
> the shared pool to get it. This can take time if the system
> has become busy, and the resulting lag in response causes
> the front end to start firing up more new sessions. These
> then hammed the shared pool and library cache latches
> as they try to demand their large contiguous chunks of
> memory. This locks up the system for everyone, causes
> the front-end panic and send in lots more new connection
> requests.
>
> Eventually no more sessions can connect, the shared pool
> has been cleaned out, and the incoming connections get
> in - and have nothing to do.
>
> Check, immediately after a freeze, if the shared pool has
> a very large free memory component. If so, modify the
> parameters for the connection library you are using so
> that it is more cautious about the number and rate of
> new connections it tries to make; and consider increasing
> the size of your shared_pool_reserve to allow for
> about 26KB * sessions plus a few dozen MB - which should
> help to protect your shared pool from a logon storm.
>
>
>
> --
> Regards
>
> Jonathan Lewis
> http://www.oracle.com/technology/community/oracle_ace/ace1.html#lewis
>
> The Co-operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
> Cost Based Oracle: Fundamentals
> http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html
>
>
> <oaksong_at_hotmail.com> wrote in message
> news:1159288666.136260.9090_at_i42g2000cwa.googlegroups.com...
> > I've got a situation where a user (the application) is randomly maxing
> > the available sessions for no apparent reason. Someone will start the
> > application or be doing something in the application and all of a
> > sudden the number of sessions assigned to the individual will start to
> > multiply at the rate of two to three per second until the max sessions
> > is reached. These sessions will remain open until they are timed out.
> > They never show as active. And of course, with no sessions available,
> > everyone else is blocked from using the application.
> >
> > The application is Visual Basic against an Oracle release 10 server. We
> > have tried to make this happen, but it's totally random as to when it
> > occurs. The way the application is constructed it does not maintain an
> > open connection to the server. That is, when it needs data it opens a
> > connection, gets the data and closes the connection. The app traps any
> > Oracle errors and attempts to write them to the database. The only
> > error we've gotten that might be related to the event is a TNSListener
> > error. "Listener failed to start a dedicated process."
> >
> > I should also mention that this is a recent development for an
> > application and server that have been behaving just fine for months.
> >
> > Any ideas would be greatly appreciated.
> > Chris
> >
Received on Tue Sep 26 2006 - 16:23:15 CDT
