BUG: Loop in COMTI After CICS ABEND During Send Processing

ID: Q191865

The information in this article applies to:

Microsoft COM Transaction Integrator for CICS and IMS versions 1.0, 1.0 SP1, included with SNA Server versions 4.0, 4.0 SP1, respectively

SYMPTOMS

If Service Pack 1 is not installed, the following symptoms appear:

1. The COM Transaction Integrator component in the Microsoft Transaction

   Server (MTS) writes messages to the application event log until it is
   full. The specific message is presented in MORE INFORMATION below.

2. An SNA APPC API trace shows a RECEIVE_WAIT loop, with the response being

   a PARAMETER_CHECK. Example trace entries are presented in MORE
   INFORMATION below.

With Service Pack 1 installed, the symptoms are slightly different:

1. An SNA Server APPC API trace shows a similar repetitive pattern, but the

   entries are named differently, that is, MC_RECEIVE_AND_POST instead of
   MC_RECEIVE_AND_WAIT. Trace examples are presented in MORE INFORMATION
   below.

2. Only one entry is written to the application event log.

CAUSE

The problem is caused when the CICS program terminates abnormally (ABENDs) in the midst of, or following, repetitive SENDs to return variable-length reply data to COMTI. COMTI fails to properly handle the message coming back from the mainframe that indicates the application program terminated abnormally. Instead, COMTI continues to incorrectly expect more of the variable-length data being returned, hence the MC_RECEIVE_AND_WAIT loop.

STATUS

Microsoft has confirmed this to be a problem in Microsoft COM Transaction Integrator for CICS and IMS versions 1.0 and 1.0 SP1, included with SNA Server versions 4.0 and 4.0 SP1, respectively. A supported fix is now available, but has not been fully regression- tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Product Support Services for more information.

MORE INFORMATION

The application event log entry is as follows:

   Event ID: 401
   Source: COMTI
   Type: Warning
   Category: General

  (401) COM Transaction Integrator Received SNA-defined Error Log Data
   text:

   DFHAC2206 14:19:08 <Remote APPC LU> Transaction <tttt> failed with abend
   <aaaa>. Updates to local recoverable resources backed out.

Explanation:

The host LU terminated the conversation with COM Transaction Integrator abnormally and sent information about the error. The message text of the SNA Error Log GDS Variable is displayed above.

Trace entries when SP1 is NOT installed:

   APPC  MC_RECEIVE_AND_WAIT request
   APPC
   APPC  Type:Sync                                  VerbID:0001C000
   APPC
   APPC  ---- Verb Parameter Block at address 00EFEF8C ----
   APPC  0B000100 00000000 00000000 00000000     <................>
   APPC  00A17700 C0A37700 00000100 00000900     <..w..tw.........>
   APPC  00000000 90C90A00 00000000 00000000     <.....I..........>
   APPC  ------------------------------------------------------------------
   --------------
   APPC  MC_RECEIVE_AND_WAIT response, result = PARAMETER_CHECK
   APPC
   APPC  Type:Sync                                  VerbID:0001C000
   APPC
   APPC  ---- Verb Parameter Block at address 00EFEF8C ----
   APPC  0B000100 00010000 00000002 00000000     <................>
   APPC  00A17700 C0A37700 00000100 00000900     <..w..tw.........>
   APPC  00000000 90C90A00 00000000 00000000     <.....I..........>

Trace entries when SP1 IS installed:

   APPC  MC_RECEIVE_AND_POST request
   APPC
   APPC  Type:Sync                                  VerbID:0001C000
   APPC
   APPC  ---- Verb Parameter Block at address 00769B00 ----
   APPC  0D000100 00000000 00000000 00000000     <................>
   APPC  D0AE7700 C0A37700 00000100 00000900     <..w..tw.........>
   APPC  00000000 60B60A00 7C020000 00000000     <....`...|.......>
   APPC  ------------------------------------------------------------------
   --------------
   APPC  MC_RECEIVE_AND_POST response, result = PARAMETER_CHECK
   APPC
   APPC  Type:Sync                                  VerbID:0001C000
   APPC
   APPC  ---- Verb Parameter Block at address 00769B00 ----
   APPC  0D000100 00010000 00000002 00000000     <................>
   APPC  D0AE7700 C0A37700 00000100 00000900     <..w..tw.........>
   APPC  00000000 60B60A00 7C020000 00000000     <....`...|.......>
   APPC  ------------------------------------------------------------------
   --------------

Issue type        : kbbug
Solution Type     : kbfix

Last Reviewed: August 26, 1998