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  6. No Failure Message Is Displayed After the EIP Is Unbound When DWS Is Connected Over the Internet

No Failure Message Is Displayed After the EIP Is Unbound When DWS Is Connected Over the Internet

After the EIP is unbound, the network may be disconnected. However, the TCP layer fails to identify that the physical connection is faulty in time due to keepalive settings. As a result, the gsql, ODBC, and JDBC clients also cannot identify the network fault in time.

The duration when the database responds the disconnection message to the client depends on the settings of keepalive parameters. The specific algorithm for calculating the duration is keepalive_time + keepalive_probes x keepalive_intvl.

Values of keepalive parameters affect network communication stability. Therefore, adjust the parameter values based on service pressure and network conditions.

In the Linux environment, run the sysctl command to modify the following parameters:

  • net.ipv4.tcp_keepalive_time
  • net.ipv4.tcp_keeaplive_probes
  • net.ipv4.tcp_keepalive_intvl

For example, if you want to change the value of net.ipv4.tcp_keepalive_time, run the following command to change the value to 120 seconds.

sysctl net.ipv4.tcp_keepalive_time=120

In the Windows environment, modify the following configuration information in registry HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters:

  • KeepAliveTime
  • KeepAliveInterval
  • TcpMaxDataRetransmissions (equivalent to tcp_keepalive_probes)

If you cannot find the preceding parameters in registry HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters, add these parameters. Open Registry Editor, right-click the blank area on the right, and choose Create > DWORD (32-bit) Value to add these parameters.