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LI72053: SNAPSHOT MONITOR UDFS RUN LONGER WHEN MONITOR STREAM EXCEEDS PREDEFINED BUFFER SIZE

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • The Snapshot UDFs (i.e. SNAPSHOT_APPL_INFO) run longer when the
    monitor stream is too large causing to not fit in a fixed memory
    buffer thus causing it to spill to disk.  This results in DB2
    having to read from a file.
    
    The fixed buffer is controlled internally by a parameter
    MAX_SNAP_SZ and this APAR will allow this buffer to be
    controllable by the user to support larger monitor streams to
    fit in the buffer.
    
    You are vulnerable to this problem if when you run the snapshot
    (i.e. select from TABLE(SNAPSHOT_APPL_INFO) and take a db2trc
    with timestamp option and then examine the trace flow
    you will see calls to seek into a file inbetween calls to the
    snapshot functions.
    
    For example, the trace flow below shows the snapshot took 18
    seconds and in that same time, the reads to the file also took
    18 seconds (i.e. 48 - 30)
    
    514182        30:273710000   | | | snapshot_appl_info entry
    ending
    933541        48:847414000   | | | snapshot_appl_info exit
    
    With the file reads taking the majority of the time
    645695        30:770411000   | | | | | | | | OSSHFile::open
    entry
    ending
    933146        48:579336000   | | | | | | | | OSSHFile::read exit
    

Local fix

Problem summary

  • see problem description
    

Problem conclusion

  • First Fixed in DB2 version 9.1 fixpak 5
    

Temporary fix

Comments

APAR Information

  • APAR number

    LI72053

  • Reported component name

    DB2 UDE ESE LIN

  • Reported component ID

    5765F4104

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-02-08

  • Closed date

    2008-08-06

  • Last modified date

    2008-08-06

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    LI72054

Fix information

  • Fixed component name

    DB2 UDE ESE LIN

  • Fixed component ID

    5765F4104

Applicable component levels

  • R910 PSY

       UP

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Document Information

Modified date:
16 October 2021