IC85932: WMQ CLASSES FOR JMS. WHEN SENDING LARGE MESSAGES USING RLE COMPRESSION, MESSAGE ARRIVES WITH SOME CORRUPTED CHARACTERS

WebSphere MQ V7.5 Fix Pack 7.5.0.1

APAR status

• Closed as program error.

Error description

• When using a WebSphere MQ v7.5 classes for JMS application to
  send large JMS messages over a channel that uses RLE
  compression, the message arrives uncompressed but with some
  corrupted characters.
  
  For example, the original message snippet was :
  
  <xyz>true
  
  but the application received message is:
  
  _xyz>true
  
  Note that the first less-than symbol '<' has been replaced with
  underscore symbol '_'.
  

Local fix

• None <br/>
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All users of WebSphere MQ classes for Java/JMS applications
  that make use of RLE Message Compression when receiving
  messages.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM SUMMARY:
  When a large message (>32kB) was received that has been
  compressed using the RLE algorithm, it was possible that one
  or more bytes of the data received did not match the data
  originally compressed. The corrupted byte(s) were located at the
  boundary of the 32kB message transmission segment size of the
  data received by the WebSphere MQ classes for Java/JMS
  application.
  
  The problem occurred when a sequence of data has been compressed
  and required decompression. At the end of this decompression,
  there may have been one remaining byte left in the compressed
  buffer of the message segment received from the queue manager.
  This last remaining byte was not being copied into the
  decompressed buffer resulting in the previously received
  transmission segment's final byte being used in the received
  message data instead.
  

Problem conclusion

• This code change associated with this APAR solves the problem by
  ensuring that if there is one byte left in the buffer after a
  data sequence has been received, then it is written to the
  decompressed buffer.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Platform           v7.5
  --------           --------------------
  Multiplatforms     7.5.0.1
  
  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:

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

Fix information

• Fixed component name

  WMQ BASE MULTIP

• Fixed component ID

  5724H7241

Applicable component levels

• R750 PSY

     UP