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Intermittent TCP connections reset(Why SQL client does not response keep alive)?

    Question

  • Hi experts,

      We run SAP on SQL and we found intermittent TCP connections reset from time to time. We created a case in MS CSS and they indicated sometimes SQL clients does not response TCP keep alive packets on some specific connections? What happen? Please help.

     

    Friday, January 04, 2013 5:12 AM

Answers

  • Of course, if there is a hardware/software problem that is resulting in resets of a connection, then the Keep Alive interval will not matter.  The reset invalidates an existing connection and you are Out until you reconnect. 

    A reconnection, of course, has no context for whatever was happening before.

    If that is it, then getting someone to troubleshoot the network is probably the best answer.

    RLF

    Wednesday, January 09, 2013 6:35 PM

All replies

  • I am not an expert on this, but this MSDN blog discusses tracing down a similar problem and a workaround used until the main problem could be resolved.

    http://blogs.msdn.com/b/dataaccesstechnologies/archive/2010/06/18/using-network-trace-to-troubleshoot-intermittent-connectivity-issues.aspx

    From that blog you will see that it is not real simple to identify the root cause, but  "...we were able to implement a work around by increasing the “TcpMaxDataRetransmissions” setting to a higher value."

    Here are some instructions: http://support.microsoft.com/kb/170359 

    Something to look into.

    RLF

    PS - I used to manage a cluster of SAP servers (R3, so it was a while back) and at that time the network load was pretty light.  From my experience it is unlikely that SAP itself is the problem, although I do not know the current client setting.
    • Edited by SQLWorkMVP Friday, January 04, 2013 2:53 PM PS
    Friday, January 04, 2013 2:46 PM
  • Hi Russell,

      Thanks for your reply. In fact, I had already read that blog. I created a case in SAP OSS and I got the same response.

      Actually, I tried that before. Increasing keep alive interval may solve the problem if it is a idle connection. However,  I found TCP connections reset  intermittently happened on active connections sometimes.

      Anyway, I will try it again first.

    Monday, January 07, 2013 2:42 AM
  • Of course, if there is a hardware/software problem that is resulting in resets of a connection, then the Keep Alive interval will not matter.  The reset invalidates an existing connection and you are Out until you reconnect. 

    A reconnection, of course, has no context for whatever was happening before.

    If that is it, then getting someone to troubleshoot the network is probably the best answer.

    RLF

    Wednesday, January 09, 2013 6:35 PM