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Limited support BMC provides limited support for this version of the product. As a result, BMC no longer accepts comments in this space. If you encounter problems with the product version or the space, contact BMC Support.BMC recommends upgrading to the latest version of the product. To see documentation for that version, see BMC AMI Ops Monitor for Db2 13.1 image-2024-5-19_8-5-1.png .

Detail trace online data storage

For each active detail trace, there is a set of data collection buffers.

The buffer that is allocated by Db2 is formatted and passed to a data collector function in the BBI-SS PAS. The data collector inserts the formatted variable-length data into the trace display buffer that is associated with each active detail trace. The size of the buffer is specified by the user.

The following figure shows how the trace data is collected and stored in the buffers for display by the DTRAC service.


GUID-C73E7FC9-9CE0-4E53-B8E9-FDFA0615F25E-low.png

Three kinds of buffers are used for a detail trace:

  • Internal buffer that is filled by the Db2 Instrumentation facility

    This buffer is managed internally by BMC AMI Ops Monitor for Db2 and Db2 in extended CSA. You cannot specify its characteristics.

  • Single buffer per trace containing data allocated in BBI-SS PAS extended private area with a GETMAIN

    This buffer’s default size is specified in the BBIISPxx member of the BBI-SS PAS BBPARM data set. The size can be overridden with the use of the STORAGE parameter that is specified with the ATRAC request (valid for a summary or detail trace). Entries are wrapped (default of WRAP=YES; new data overlays oldest data) unless you specify WRAP=NO with the ATRAC request. WRAP can be changed at any time by using the M line command from the Current Traces view to modify the ATRAC request.

    Warning

    Note

    For detailed recommendations about how to set these values, see Starting-a-detail-trace.

  • Pool of data collection buffers that is maintained by BMC AMI OpsM for Db2

    A pool exists for each active detail trace in the BBI-SS PAS extended private area storage. A buffer is allocated for the CREATE THREAD function for each active thread being traced, and more might be needed as the thread progresses. By default, BMC AMI OpsM for Db2 allocates these buffers as needed. Alternatively, you can specify the size and number of these buffers with the parameters listed in the following table, which are specified in the DMRBEXxx member of the BBI-SS PAS BBPARM data set (defaults for each Db2) or in the data entry panel for the ATRAC request (see Start-DB2-Trace-Request-dialog).

    Parameter

    Description

    TRBUFF=nnn

    nnn is the number of buffers to be allocated.

    TRSIZE=nnnK

    nnn is the size in kilobytes of each buffer. If K is not specified, the value of nnn is in bytes. nnn is rounded to a multiple of 4 KB during processing.

    Warning

    Note

    ATRAC TRSIZE and TRBUFF are primed with the TRSIZE and TRBUFF values specified in DMRBEXxx. If TRSIZE or TRBUFF is defined with an ATRAC request, their values override any value specified for these keywords in DMRBEXxx.

    Information
    Example

    If DMRBEXxx specifies the following values:

    TARGET=DB2P
    TRBUFF=20
    TRSIZE=400K

    The total pool size is 20*400 KB = 8,000 KB.

Related topic

Collecting-trace-data

 

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BMC AMI Ops Monitor for Db2 12.2