ODBC DB2 Mainframe and Console errors

[Jim Kosloskey]

All,

I just sompleted a DB2 (Mainframe) Integration using the ODBC Drivers(DataDirect 5.2) and came across the following situation:

The following Console message was appearing on the MVS Console (Mainframe) with each disconnect from the DB2 database. The DBAs insisted we connect and disconnect with each mesage and this is real time so this message happened quite frequently

00- STC06927  DSNL511I  -DBP1 DSNLIENO TCP/IP CONVERSATION FAILED

   –            TO LOCATION 10.111.87.148

   –            IPADDR=10.111.87.148 PORT=37888

   –            SOCKET=RECV RETURN CODE=1121 REASON CODE=00000000

The console display needed to cease.

I searched the DataDirect Knowledge base and found there is a non-documented connection option that will eliminate this console display.

The option is TCPSocketLinger.

Apparently DB2 Mainframe cannot tolerate ‘hard’ socket closes following a successful SQL Disconnect. The default for the DataDirect Drivers is to immediately close the socket (a ‘hard’ close) upon receipt of an SQL_SUCCESS return for an SQL disconnect (this is the way one would expect the socket to be handled I think).

With the connect option above that behavior can be changed to a ‘Soft’ close (delayed socket close) which elliminates the console message. Setting the option to 1 (TCPSocketLinger=1) does the trick.

It appears that the issue could be resolved on the DB2 side (this intelligence was not in the DataDirect Knowledge Base – I located it in a DB2 forum) but that relies on:

1. changing many DB2 and apparently O/S settings which may have other unintended consequences.

2. requires someone have the requisite knowledge to know what settings to change, how to change them, and how much to change them – probably in most cases that would only be IBM support.

3. requires that the local system admin staff actually care to try and fix the issue on their side.

Moreover, I could not locate any independent confirmation that changing the indicated settings worked for more than one location.

I wanted to share this in case anyone else encounters this issue.

It was not easy to find the solution.

email: jim.kosloskey@jim-kosloskey.com 29+ years Cloverleaf, 59 years IT - old fart.

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