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  1. #1
    Join Date
    Jan 2014
    Posts
    3

    Unanswered: DB2 time spent metrics

    Hi guys,

    I'm analyzing my database in order to understand where DB2 spends his time at the system level.
    I have not created other user defined service class so I focused only on SYSDEFAULTUSERCLASS service class and I executed the following query:

    select * from table(mon_get_service_subclass_details(null,null,n ull)) as s,
    table(mon_format_xml_times_by_row(s.details))
    where (metric_name='TOTAL_RQST_TIME') OR (parent_metric_name='TOTAL_RQST_TIME')

    This is my output

    TOTAL_RQST_TIME = 570950685
    TOTAL_WAIT_TIME = 41349691
    TOTAL_COMPUTE_PROC_TIME = 383055
    TOTAL_IMPLICIT_COMPILE_PROC_TIME = 1429
    TOTAL_RUNSTATS_PROC_TIME = 238724722
    TOTAL_REORG_PROC_TIME = 40731
    TOTAL_LOAD_PROC_TIME = 178431
    TOTAL_SECTION_PROC_TIME = 9682211
    TOTAL_COMMIT_PROC_TIME = 44157
    TOTAL_ROLLBACK_PROC_TIME = 1226
    TOTAL_ROUTINE_USER_CODE_PROC_TIME = 1446833

    I expected that TOTAL_WAIT_TIME + TOTAL_*_PROC_TIME = TOTAL_RQST_TIME

    instead the result is different: TOTAL_WAIT_TIME + TOTAL_*_PROC_TIME = 291852486
    TOTAL_RQST_TIME = 570950685

    Can someone explain why there is this difference?

    Thanks

  2. #2
    Join Date
    Jul 2013
    Location
    Moscow, Russia
    Posts
    666
    Provided Answers: 55
    Hi,

    According to the Figure 2 of the Hierarchy of time-spent monitor elements
    each of the total_*_proc_time metric is part of the corresponding parent total_*_time metric.
    You can see the difference using MON_FORMAT_XML_COMPONENT_TIMES_BY_ROW function.

    So it seems that we should assume that
    TOTAL_WAIT_TIME + TOTAL_*_TIME = TOTAL_RQST_TIME
    But often there is a noticeable difference between this sum and total_rqst_time.
    Probably those "Other[1|2]" are not so tiny...
    Regards,
    Mark.

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