Topic
4 replies Latest Post - ‏2014-07-15T20:50:22Z by rcausley
amccarl
amccarl
73 Posts
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Pinned topic TCP/IP keepalive settings and related DB2 registry variables

‏2013-06-12T21:21:17Z |

TCP/IP uses operating system keepalive parameters to detect when the client or server side of an idle connection is no longer responding. DB2 sets the TCP/IP keepalive setting on both the client and server by default.

You may wish to decrease the keepalive parameters on the server side machine to improve detection of client failures, or decrease the keepalive parameters on the client side machine to improve detection of server failures. Alternatively, you may wish to increase the keepalive parameters on the server side machine to prevent client disconnects on idle connections, or increase the keepalive parameters on the client side machine to prevent server disconnects on idle connections.

Each keepalive parameter comes with a default setting; many parameters are configurable. In general, the parameters:

  • Determine how long to wait before probing the idle connection. On most platforms the default is 2 hours.
  • Determine how long to wait before retrying the probe after initial failure to respond.
  • Determine the maximum number of times to retry the probe.


Modifying any keepalive parameter may involve trade-offs and affects applications on your entire machine. For example, changing these parameters affects rlogin, ssh, and telnet. You may wish to reset additional TCP/IP parameters, depending on the overall impact to other TCP/IP parameters. Contact your operating system administrator for help with setting these values.  describes how to display and modify keepalive values on various operating systems.

Technical article 1231084 describes how to display and modify keepalive values on various operating systems:

http://www-01.ibm.com/support/docview.wss?uid=swg21231084

 

Updated on 2013-06-14T14:35:09Z at 2013-06-14T14:35:09Z by amccarl
  • amccarl
    amccarl
    73 Posts
    ACCEPTED ANSWER

    Re: TCP/IP keepalive settings and related DB2 registry variables

    ‏2013-06-14T14:23:07Z  in response to amccarl
    Hello!  We've had a number of clients respond through feedback to our technical documents indicating that they have further questions or comments that require additional dialogue.  Unfortunately, our feedback is anonymous, so unless an email address or other contact information is included, we have no way to get back in touch with you.
     
    Within DB2 support, the management team asked if we could somehow link our documents to the forums so that we could invite more discussion - like this!   As a start, we chose about 30 technical articles and "seeded" the forum with initial entries so that we could have a starting place for conversation.  The documents have now been updated with links to the forums as well.  
     
    Hopefully, we will make DB2 support better by providing more interaction around our technical information!
     
  • rcausley
    rcausley
    2 Posts
    ACCEPTED ANSWER

    Re: TCP/IP keepalive settings and related DB2 registry variables

    ‏2014-05-12T20:27:10Z  in response to amccarl

    Hi,

    We received the following question via the feedback mechanism and we'll answer it here:

    Are these DB2 registry variables applicable to Java programs (jcc driver) as well?

    Most of the DB2 registry variables discussed do not apply to the JDBC driver. The exception is DB2CHECKCLIENTINTERVAL which is a server-side setting for the LUW server. As for the rest of the DB2 registry variables, the equivalent JDBC driver properties are as follows:

    connectionTimeout
    blockingReadConnectionTimeout
    keepAliveTimeOut