IT04083: WEBSPHERE MQ R531.10 ON NSS QUEUE SERVERS MAY RECEIVE RC30 IF THEY ARE IN A COMPLEX ENVIRONMENT USING MQGMO_SET_SIGNAL

WebSphere MQ for HP NonStop Server V5.3.1 fix pack 5.3.1.11

APAR status

• Closed as program error.

Error description

• Fixpack 10 for WebSphere MQ r531 for Non Stop Server, NSS,
  attempted to increase the Message Quick Cell, "MQC's", limit for
  MQ processes. Message Quick Cell, "MQC's", are a system resource
  that are used to deliver messages (I-O). By default a limit of
  1023 is set for all processes by the operating system.  This
  results in additional processing to obtain more when needed.
  This would be avoided by having a larger upper limit from the
  outset. Increasing this limit does not affect processes, it only
  allows additional "MQC's" to be used, if they are needed.
  In a large queue manager more than 1023 "MQC's" may be required.
  When MQ attempts to use more than 1023 "MQC's" the Queue Server
  receives a return code 30.  Error 30 = Message system is unable
  to obtain memory because either no entry is available in the
  message block pool or the maximum number of RECEIVE or SEND
  message blocks are already in use.
  

Local fix

• Set the MQQSCONTROLSEND PARAM in the Pathway Queue Server
  serverclass to a value between the default value 1023 and 4079.
  Any value in this range will work around this issue.
  

Problem summary

• Fixpack 10 for WebSphere MQ r531 for Non Stop Server, NSS,
  attempted to increase the Message Quick Cell, "MQC's", limit fo
  MQ processes. Message Quick Cell, "MQC's", are a system resourc
  that are used to deliver messages (I-O). By default a limit of
  1023 is set for all processes by the operating system.  This
  results in additional processing to obtain more when needed.
  This would be avoided by having a larger upper limit from the
  outset. Increasing this limit does not affect processes, it onl
  allows additional "MQC's" to be used, if they are needed.
  In a large queue manager more than 1023 "MQC's" may be required
  When MQ attempts to use more than 1023 "MQC's" the Queue Server
  receives a return code 30.  Error 30 = Message system is unable
  to obtain memory because either no entry is available in the
  message block pool or the maximum number of RECEIVE or SEND
  message blocks are already in use.
  

Problem conclusion

• The Queue Server has been changed to call GPC
  CONTROLMESSAGESYSTEM to set the maximum limit on the number of
  outstanding messages sent by the process to 4000.
  

Temporary fix

• Set the MQQSCONTROLSEND PARAM in the Pathway Queue Server
  serverclass to a value between the default value 1023 and 4079.
  Any value in this range will work around this issue.
  

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

  WEBS MQ NSS ITA

• Fixed component ID

  5724A3902

Applicable component levels