Re: Dead Clients with SQL*Net and TCP/IP

From: Gilles BRUNO <Gilles.Bruno_at_ujf-grenoble.fr>
Date: 1995/08/31
Message-ID: <423nfq$nln_at_ujf.ujf-grenoble.fr>#1/1


dischner_at_med.uni-muenchen.de (Anton Dischner) wrote:

>Hi Guenter,
>enter tcpctl -?
>the standard timeout is set to 0 seconds (off).
>Try to set it to a reasonable time.
>Please drop me a note if this (and what value) solves your problem.
 

>In article <41rnmr$2t60_at_news-s01.ny.us.ibm.net>, brorsg_at_ibm.net (Guenter
>Brors) wrote:
 

>> When an MS-Windows client crashes or the PC is turned off without
>> properly ending the application, the session on the Oracle server
>> remains forever open. This is a waste of ressources, apart from DBMS
>> locks that may also be held forever and block other users.
>>
>> It seems that the underlying TCP/IP is used by SQL*Net without the
>> KEEPALIVE option, which could help in detecting dead clients. Is there
>> any way to turn on this option ?
>>
>> I do not want a DBA to regularly check on the server side and manually
>> kill dead sessions. I want an application that can turn 24 hours a day
>> without administration.
>>
>> I'm using Oracle 7.1.16 on RS/6000 and SQL*Net 2.0 with Pro*Cobol and
>> ODBC on MS-Windows.
>>
>> Please let me know how you solved this problem.
>>

An other solution Oracle customer support people gave me was on AIX to configure the Unix kernel so as to make it check and validate the Tcp/Ip connexions more frequently Normally it has not to be donne while communicating with regular unix boxes, but the PC's tcp/ip kernel does not behave as well as the other do (in the case off a GPF or a power down for example).

On AIX you could use the 'no' (network option) command so as the decrease the 'tcp_keepidle' time : by default it checks the tcp connexions every 2 hours (in that case the Rdbms really knows your client is 'dead' 2 hours after it crashes - and so PMON close it's sql*net shadow process and the corresponding Oracle session is automatically closed).

You can decrease this parameter to make it nears 15 minutes but BEWARE that the lower it will be, the higher would be the network traffic (it generates many brodcasts for each connected client)...

Hope this helps.


   ('<      Gilles BRUNO.   Universite Joseph Fourier.
  ,',)      Tel: +33 76 63 56 68    Fax: +33 76 51 42 74
 ''<<       E-mail: Gilles.Bruno_at_ujf-grenoble.fr
----""-------------------------------------------------------
Received on Thu Aug 31 1995 - 00:00:00 CEST

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