IT30847: MQ Managed .Net client connecting to queue manager fails intermittently with MQRC 2195

APAR status

• Closed as program error.

Error description

• MQ Managed .Net client application while authenticating the
  connection, intermittently fails with MQRC
  2195(MQRC_UNEXPECTED_ERROR).
  
  MQ trace shows below errors :-
  
  00000484 17:17:15.206717  7924.20     Data Length --> 48
  00000485 17:17:15.206717  7924.20    Send >>
  00000486 17:17:15.206717  7924.20   -----------{
  MQEncryptedSocket..Write(byte[], int, int)
  00000487 17:17:15.206717  7924.20    Writing 48 bytes onto wire
  0000050E 17:17:15.220717  7924.20
  System.NotSupportedException: The BeginWrite method cannot be
  called when another write operation is pending.
    at System.Net.Security._SslStream.ProcessWrite(Byte[] buffer,
  Int32 offset, Int32 count, AsyncProtocolRequest asy
  ncRequest)
    at System.Net.Security._SslStream.BeginWrite(Byte[] buffer,
  Int32 offset, Int32 count, AsyncCallback asyncCallback, Object
  asyncState)
    at IBM.WMQ.Nmqi.MQEncryptedSocket.Write(Byte[] buffer, Int32
  offset, Int32 length)
  0000050F 17:17:15.221717  7924.20   -----------}
  MQEncryptedSocket..Write(byte[], int, int) rc=OK
  00000510 17:17:15.221717  7924.20    Send << - n = 0
  00000511 17:17:15.221717  7924.20
  System.NotSupportedException: The BeginWrite method cannot be
  called when another write operation is pending.
    at IBM.WMQ.Nmqi.MQEncryptedSocket.Write(Byte[] buffer, Int32
  offset, Int32 length)
    at IBM.WMQ.MQTCPConnection.Send(Byte[] bytes, Int32 offset,
  Int32 length, Int32 segmentType, Int32 tshType)
  00000512 17:17:15.222717  7924.20    New MQException CompCode: 2
  Reason: 2195
  00000513 17:17:15.222717  7924.20    New NmqiException CompCode:
  2 Reason: 2195
  

Local fix

• Alter the channel definition to use SHARECNV(1) so that each
  logical connection within the .NET application uses a unique
  socket.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users who are using managed MQ .Net application.
  
  
  Platforms affected:
  Windows
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A logic error within the managed .NET client meant that when
  multiple logical connections were opearting over the same
  channel instance (SHARECNV > 1), it was possible for 2 threads
  to attempt to concurrently write to the socket used for that
  channel instance. This resulted in the .NET runtime reporting
  the following error:
  
  " System.NotSupportedException: The BeginWrite method cannot be
  called when another write operation is pending. "
  

Problem conclusion

• The locking mechanism in managed MQ .NET code has been corrected
  to correctly serialize writes to the socket when multiple
  connections are using the socket with SHARECNV > 1.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.11
  v9.1 LTS   9.1.0.6
  v9.x CD    9.2.0
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IT30163

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  IBM MQ BASE MP

• Fixed component ID

  5724H7271

Applicable component levels