IT43831: IBM MQ Channels Might Go Unresponsive With High CPU Usage in Channel Process If Channel Synchronization Record is Corrupted

APAR status

Closed as program error.

 

Error description

IBM MQ channels might go unresponsive with high CPU usage in channel process amqrmppa or runmqchl if the channel synchronization record is corrupted.  If the problem affects the channels on the SENDER side(e.g. SDR or CLUSSDR) channels  then no message will be sent by the channels. The “DIS CHS” output likely to show no value in the SUBSTATE field.

 

AMQ8417I: Display Channel Status details.

CHANNEL(CLUSCHL1)      CHLTYPE(CLUSSDR)

…

RQMNAME(RQM1)            STATUS(RUNNING)

SUBSTATE( )

XMITQ(SYSTEM.CLUSTER.TRANSMIT.CLUSCHL1)

 

If the affected channels are on the receiver side (e.g. RCVR or CLUSRCVR) then the channel process on the receiver side consumes high CPU with the corresponding SDR or RCVR channel going into retrying state.

The top output for the affect channel process shows high CPU usage.

 

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM

TIME+ COMMAND

133101 mqm       20   0  265412  13836  11584 R 106.2   0.4

2:08.97 runmqchl

133101 mqm       20   0  265412  13836  11584 R   99.7   0.4

2:11.97 runmqchl

133101 mqm       20   0  265412  13836  11584 R   99.3   0.4

2:14.97 runmqchl

133101 mqm       20   0  265412  13836  11584 R   99.7   0.4

2:17.97 runmqchl</