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- Newsgroups: vmsnet.sysmgt
- Path: sparky!uunet!unx1!dean
- From: dean@unix1.realdec.com (Dean Banfield)
- Subject: Re: Lost LAT sessions
- Organization: Real Decisions Corporation
- Date: Mon, 25 Jan 1993 22:20:05 GMT
- Message-ID: <DEAN.93Jan25172005@unix1.realdec.com>
- In-Reply-To: Peter Smode's message of Fri, 22 Jan 93 15:27:20 PST
- References: <0NXsXB1w165w@jeslacs.wimsey.bc.ca>
- Sender: dean@rdcalr.realdec.com (Dean Banfield)
- Lines: 57
-
- In article <0NXsXB1w165w@jeslacs.wimsey.bc.ca> Peter Smode <psmode@jeslacs.wimsey.bc.ca> writes:
-
- > - a SHOW USERS FULL will be missing the (server/port) address for the
- > LTAxxx: terminal
- > - the process will INHALE all available CPU time, at elivated priority.
- > This effectively turns the system into a dog.
- > - it is suspected that users terminal sessions just go dead in the
- > water with no terminal response. We are not sure as users are not
- > giving us good information when these situations occur.
-
- We have a software product which experienced a similar problem when
- installed at one particular client. We narrowed it down to the following
- criteria:
- User logged on via LAT
- Hanging out in our product at our prompt (read wait on SYS$INPUT)
- User walks away, uses other session on terminal server, etc and
- forgets about his read prompt in our product.
- He then logs off terminal server without actually exiting from the
- product prompt, or logging off that session independently.
- LAT sends a HANGUP message to the process, which attempts to
- wind down the image. This is unsuccessful and the image is
- left disconnected from any LAT connection and gets very high
- priority in the attempted wind-down.
- We traced the problem to a set of CTL-C, CTL-Y trapping routines which we
- had implemented. In effect, the wind-down operation sent a CTL-C (or Y)
- to the image to wind it down. Our software, assuming that this was an
- interactive user, trapped the signal and tried to return the user to the
- product prompt. Having no effective terminal any more, the software got
- very confused and sucked down all available resources trying to re-issue
- the product prompt.
-
- To stop the bleeding (we never found an elegant solution) we simply advised
- the client to disable the CTL-C, CTL-Y trapping, which meant that when a
- user aborted out of our product, we allowed the system to wind it down in
- its own (possibly nasty to us) way. This DID stop the problem.
-
- My advice: Try to find out what application user/application was "turned
- off" in this way. Approach the developer of the application with these
- ideas and see what falls out. It may be difficult to track this down, but
- in our case our image was easily identifiable to the system manager as the
- one trying to wind itself down. The user was impossible to find, since the
- LAT stuff got disconnected early in the wind-down.
-
- Hope this is of some help.
-
- -Dean
- --
- ===============================================================
- Dean Banfield
- Real Decisions Corporation Voice: 203.656.1500
- 22 Thorndal Circle FAX: 203.656.1659
- Darien, CT USA 06820 Email: dean@rdcalr.realdec.com
- --
- ===============================================================
- Dean Banfield
- Real Decisions Corporation Voice: 203.656.1500
- 22 Thorndal Circle FAX: 203.656.1659
-