4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 06013: Msg Queue Forced Write Percentage Exceeds Standard

06013: Msg Queue Forced Write Percentage Exceeds Standard

    FILE:            IMS System Activity
    SAS FILE NAME:   DETAIL.IMSISY01
    SOURCE LOCATION: sharedprefix.MICS.SOURCE(DYIMSEXC)

    SEVERITY:        Impacting     (SEVERITY='I')
    MANAGEMENT AREA: Performance   (MGMTAREA='PERFORMANCE')

    PURPOSE:  Identifies the time period during which the
message queue pool was over-committed.

    RATIONALE:  An abnormally high message queue pool forced
write percentage indicates complex message traffic which
required I/O to the message queue data sets.  Ideally,
message processing takes place with no I/O to these data
sets.  Simple message traffic, which is processed before the
space in the pool is required for other traffic, generates
minimum I/O.  This may be caused by a message processing BMP
or user misuse of transactions.  System performance is
extremely sensitive to activity in this pool.  This number is
affected by the complexity of message traffic as well as
volume.  The theoretical maximum for this number is fifty
(50) percent as all traffic written must then be read again
to be processed.  A large percentage of forced writes
indicates the pool is too small.

    DEFINITION:  This exception is detected when the message
queue pool forced write percentage exceeds the installation
defined limit.

    EXCEPTION STATEMENTS:  The SAS statements identifying the
exception situation and describing the condition are stored
in the source member named in SOURCE LOCATION and are
described below:

*
**  06013
**  MESSAGE QUEUE FORCED WRITE PERCENTAGE EXCEEDS STANDARD
*;
IF ISYPCMQF > forced-write-percentage
 THEN DO;
  EXCCODE='06013'; SEVERITY='I'; MGMTAREA='PERFORMANCE';
  EXCDESC1=
  'MESSAGE QUEUE FORCED WRITE PERCENTAGE EXCEEDS STANDARD';
  EXCDESC2='MSG QUEUE FORCED WRITES PERCENTAGE = '
           || PUT(ISYPCMQF,7.2);
  LINK HIT;
END;

    THRESHOLD MODIFICATION:  Modify the message queue
forced-write-percentage to a value between 0 and 50.