Event 94 Continuously Logged on COMTI Client

• Microsoft SNA Server, versions 4.0, 4.0SP1

SYMPTOMS

A computer running Microsoft Transaction Server, COMTI, and the Windows SNA client may repeatedly log the error below in the Windows NT Application Event log when multiple instances of COMTI are using one local APPC LU on SNA Server. The only way to stop the event from being logged is to stop SnaBase.

Event ID:  94
APPC remote conversation start failed:

   Primary_rc   = 0002
   Secondary_rc = 00000509
   TP name      =

EXPLANATION
An invokable APPC TP configured on SNA Server has issued a RECEIVE_ALLOCATE
verb that failed.

ACTION
Refer to the "Microsoft SNA Server APPC Programmer's Guide" for information
about the displayed primary_rc and secondary_rc values. 

CAUSE

The Resync TP service runs on the COMTI computer, and it is used for two-phase commit. The error occurs when the Resync TP service is enabled, and multiple COMTI computers are trying to use the same local APPC LU on the SNA Server computer.

WORKAROUND

To work around this problem, if the COMTI transaction program does not use two-phase commit, and no instances of COMTI require a transaction, stop the Resync TP service on the computer running COMTI, and set the Startup value to Manual. In addition, if the COMTI components do not require transactions, the SyncPoint Support option should not be checked in the properties of the local APPC LU being used on SNA Server.

RESOLUTION

To resolve this problem, associate each instance of COMTI to its own local APPC LU on the SNA Server computer, as opposed to associating all the instances of COMTI to the same local APPC LU.

MORE INFORMATION

Two-phase commit is a protocol that ensures that transactions which take place on multiple servers are completed on all servers or none at all. In other words, if a transaction fails on one server, then the changes that took place on the other servers are backed out. The resynchronization service is used in conjuction with two-phase commit and allows Distributed Transaction Coordinator (DTC) and CICS to initiate the rollback process after there has been an outage of some sort. For example, a communications failure, a CICS failure, an MVS failure, and so forth. Resync TP monitors the situation, and when the partner comes alive again, it ensures that a proper "Exchange Log Names(XLN)" is performed between the two ends (DTC and CICS). This is how they synchronize after an outage. At the time, it may be discovered that everything is OK. Otherwise, the transaction that was in-flight at the time of the outage will be rolled back. Each COMTI computer must have its own local APPC LU configured on the SNA Server for two-phase commit to function properly, because each local APPC LU is associated to one CICS region on the host.

Additional query words:

Keywords :
Version : WINDOWS:4.0,4.0SP1
Platform : WINDOWS
Issue type : kbprb