Exception processing

Exception processing identifies Statistics report, trace, and File data set entries with fields that contain values outside the thresholds specified in the Exception Threshold data set. When exception processing is active, the data to be reported is checked against these thresholds.

There are two threshold types that you can set: warning and problem. A warning message is printed if a value is outside the first threshold and a problem message is printed if a value is outside the second threshold.

When exception processing is requested for a File data set, only delta records in exception status are included in the output data set.

Statistics exception reports, traces, and File data sets are identical to the usual Statistics reports, traces, and File data sets, except that they only contain interval records and delta records that have at least one field in exception status.

When delta records and interval records are processed during exception processing, values defined in the Exception Threshold data set are compared with the corresponding values in a delta or interval record. If any field is in exception status, the following occurs:

If the JCL contains a valid DD statement for EXTRCDD1 or EXFILDD1, the identity of the delta or interval record (timestamp and subsystem identification) and the fields in exception status are logged in the exception logs.
If you specified EXCEPTION with the REPORT, TRACE, or FILE subcommand, the interval or delta record is formatted and printed (or filed in case of the FILE subcommand) in the requested layout followed by the Exception Messages block of the report. An example is shown in Statistics Exception Messages report block. The Exception Messages block of the report identifies the fields in exception status.

Note:

The type of layout used has no effect on exception processing or on the content of the Exception Messages block of the report. All fields in exception status are reported. The layout used only affects the level of detail in the formatted interval or delta record. This means, the exception report can contain fields that have not been included in the corresponding trace or report.
For group-scope reports, exceptions are checked only against the interval records that are aggregated across a data sharing group. However, member-specific statistics are shown wherever exceptions are found for the entire group.

The fields that caused the entry to be in exception status are identified along with the appropriate warning or problem message and are printed in the Exception Messages block of the report or trace.

Statistics Exception Messages report block shows an example of an Exception Messages block . It is printed after each interval or delta record that is found to be in exception status, provided that EXCEPTION was specified in the REPORT or TRACE subcommand.

Statistics Exception Messages report block

Here is an example of a Statistics Exception Messages report block.



  **********************************************************************************************************************************
  *  TYPE           FIELD ID   FIELD DESCRIPTION                                      BY                     VALUE   THRESHOLD     *
  *                            FIELD QUALIFIER                                                                                     *
  *  PROBLEM        QBSTRIO    SYNCHRONOUS READS                                      TOTAL                     53 > 50            *
  *                            BP0                                                                                                 *
  *  WARNING        QBSTRIO    SYNCHRONOUS READS                                      TOTAL                      9 > 1             *
  *                            BP2                                                                                                 *
  *  WARNING        QBSTRIO    SYNCHRONOUS READS                                      TOTAL                      9 > 1             *
  *                            BP7                                                                                                 *
  **********************************************************************************************************************************

The following columns are presented in the Exception Messages report block:

TYPE

The type of exception. Valid values are WARNING and PROBLEM.

FIELD ID

The name of the field from the Exception Threshold data set.

FIELD DESCRIPTION

The description of the field.

FIELD QUALIFIER

The qualifier of the field. This is either the buffer pool ID, the group buffer pool ID, or the remote location. This field is blank if there is no field qualifier.

BY

The basis for the comparison. The following information can be printed in this column:

TOTAL: The threshold is specified as a total value.
MINUTE: The threshold is specified as a by minute value. The value in the interval or delta record is divided by the number of minutes in the interval or delta before making the comparison.
SECOND: The threshold is specified as a by second value. The value in the interval or delta record is divided by the number of seconds in the interval or delta before making the comparison.
COMMIT: The threshold is specified as a by commit value. The value in the interval or delta record is divided by the number of Commits in the interval or delta before making the comparison.
THREAD: The threshold is specified as a by thread value. The value in the interval or delta record is divided by the number of threads in the interval or delta before making the comparison.

VALUE

The actual field value that is used for the comparison. For total comparisons, the value from the interval or delta record is printed. For by minute, by second, by commit, or by thread comparisons, the calculated by minute, by second, by commit, or by thread value is printed. The greater than symbol (>) or the less than symbol < is printed between this column and the THRESHOLD column, which indicates whether the value is larger or smaller than the threshold value.

THRESHOLD

The threshold defined in the Exception Threshold data set.