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Former Member
Apr 14, 2010 at 06:01 AM

SQL30081N connection errors when DNS server goes off-line

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Currently have a strange problem with some (but not all) database connections when one of our DNS servers goes offline.

We have multiple DNS servers configured in the /etc/resolv.conf file and at least one of these servers is always available to the AIX server and SAP system. If we take down a single DNS server for maintenance the following errors start to occur in some of our SAP systems ->

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Database error -30081 requires database administrator to intervene

Database error -30081 at INS access to table SWT_LOGCAT

> SQL30081N A communication error has been detected.

> Communication protocol being used: "TCP/IP". Communication

> API being used: "SOCKETS". Location where the error was

> detected: "10.26.4.41". Communication function detecting th

> error: "selectForRecvTimeout". Protocol specific error

> code(s): "78", "", "". SQLSTATE=08001

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Only SAP systems with patch level equal or greater than Kernel 7.01 patch 55 (DBSL patch 53) get the problem, all other systems (on the same AIX host!) which have 7.00 kernels and even a 7.01 patch 23 kernel do not get the problem at all.

To make matters more confusing we adjusted the /etc/resolv.conf file on the production server so it did not reference the DNS server that needs maintenance, out of four systems on that host the one running a 7.01 patch 55 kernel continued to have SQL30081 errors when the DNS host was down until it was restarted. So it took a SAP restart to pick-up an OS DNS change....

We don't believe there is an underlying DNS problem, since the problem only occurs with kernels above 7.01 patch 55. Wondering if anyone else has had similar problems or happens to have a similar mix of kernels and might be able to try and replicate it.

AIX 5.3

DB2 V9.5 FP5

Kernel 7.01 patch 55 above = bad

Thanks

Daniel