IT26707: amqsevt sample uses high CPU when running as an IBM MQ Service

APAR status

• Closed as program error.

Error description

• When starting the sample amqsevt as an IBM MQ Service then
  commands such as top or ps show the amqsevt process using
  almost 100% of a CPU core.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users who wish to run the amqsevt sample as an IBM MQ Service on
  a non-Windows Operating System will be affected
  by this problem.
  
  
  Platforms affected:
  Solaris x86-64, Solaris SPARC, Linux on zSeries, Linux on
  x86-64, Linux on x86, Linux on S390, Linux on Power, IBM
  iSeries, HP-UX OpenVMS, HP-UX PA-RISC, HP-UX Itanium, AIX
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When IBM MQ starts a service, it assigns the stdin file
  descriptor to /dev/null.  Some interactive applications such as
  amqsevt may not function correctly in this environment.  In the
  case of amqsevt, the select() call in the input loop would
  constantly be woken up by bytes being sent to it from /dev/null
  and so the sample would enter a tight loop.
  

Problem conclusion

• The amqsevt sample has been modified to detect whether a
  terminal is being used for stdin.  If it is not then the sample
  sleeps for 5 seconds in a loop rather than waiting for input.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.6
  v9.1 CD    9.1.2
  v9.1 LTS   9.1.0.2
  
  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

  IBM MQ BASE M/P

• Fixed component ID

  5724H7261

Applicable component levels