IBM Support

IY98624: SLOW PERFORMANCE WITH HIGH SYSTEM CPU ON HP-UX PA-RISC (PROBLEM ALSO OCCURS ON OTHER OPERATING SYSTEMS)

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • One may experience slow performance when performing a large
    number of data reads in a unicode UTF8 database on a
    HP-UX PA-RISC system, or other OS platforms.
    .
    A relatively high system CPU usage can be seen in various OS
    and DB2 snapshots.  For example, a DB2 Application Snapshot
    shows
    .
    Application handle                         = 24
    Application status                         = UOW Executing
    :
    :
    Total User CPU Time used by agent (s)      = 97.214946
    Total System CPU Time used by agent (s)    = 646.237352
    Host execution elapsed time                = 872.431481
    :
    :
    Total Statement user CPU time              = 16.905743
    Total Statement system CPU time            = 162.906992
    .
    Note the high system CPU time values.
    .
    .
    A system vmstat shows:
    .
      2:21pm  up  8:07,  4 users,  load average: 1.37, 0.86, 0.59
             procs           memory                   page
        r     b     w      avm    free   re   at    pi   po    fr
       14     1     0  2784832  2426482  395   51     4    0     0
       14     1     0  2784832  2425874  230   16     0    0     0
       14     1     0  2784832  2424626  153   11     0    0     0
       14     1     0  2784832  2424034  132   11     0    0     0
       14     1     0  2784832  2423390  409   28     0    0     0
       14     1     0  2784832  2422783  395   22     0    0     0
       14     1     0  2784832  2422046  316   17     0    0     0
       14     1     0  2784832  2421598  253   13     0    0     0
       13     1     0  2544918  2420894  202   10     0    0     0
       13     1     0  2544918  2420398  211   26     0    0     0
                        faults       cpu
    de    sr     in     sy    cs  us sy id
      0    56   2267 101452 10012  11 15 74
      0     0   2335 291476 96803  35 55 10
      0     0   2314 294915 96359  33 53 14
      0     0   2301 278713 97107  31 52 17
      0     0   2299 283457 96397  38 55  7
      0     0   2279 284474 95123  37 48 16
      0     0   2284 286336 96034  35 53 12
      0     0   2274 285391 96105  36 50 14
      0     0   2294 286326 97367  36 53 11
      0     0   2314 278784 95933  39 49 12
    .
    Again, note the relatively higher system CPU cycles % column.
    .
    Iterative stack dumps of DB2 processes capture many agents
    with stacks similar to the following.  However, iterative
    stack dumps for the same process may show that the agent is
    active, although may be progressing slowly and not necessarily
    show the same stack on each iteration.
    .
    ossDumpStackTraceInternal + 0x5c
    ossDumpStackTrace + 0x48
    dump__11OSSTrapFileFUliP9__siginfoPv + 0x170
    sqlo_trce + 0x2b8
    sqloDumpDiagInfoHandler + 0xd0
    _sigreturn
    keypart_varUTF8S__FP7SQLI_CBP10sqlz_valuePPcP17COMP_FUNC_ELEMENT
    sqliCompare__FP7SQLI_CBP14SQLI_PAGE_DESCP8SQLD_KEYP12SQLI_KEYDAT
    sqliBinSearchFirstRidOrNext__FP7SQLI_CBiN22P14SQLI_PAGE_DESCP8SQ
    fetchko__FP7SQLI_CBP14SQLI_PAGE_DESCP8SQLD_KEYP9SQLI_SLOTi + 0x7
    sqlilkey__FP7SQLI_CBiP14SQLI_PAGE_DESCP8SQLD_KEYP12SQLI_KEYDATAT
    sqlischf__FP7SQLI_CBUsUi + 0x20c
    sqliFirstTreeSearch__FP7SQLI_CBP11SQLI_SFGLOB + 0x5c
    sqlirdk__FP20sqle_agent_privatecbP10SQLI_IXPCRP9SQLD_IXCBUlP8SQL
    sqldIndexFetch__FP8SQLD_CCBP8SQLZ_RID + 0x13c
    sqldRowFetch__FP20sqle_agent_privatecbP8SQLD_CCBUlT3PP10SQLD_VAL
    .
    The above stack indicates index keys are being read, and bytes
    of key data are being compared for qualifying matches.  However,
    the memory buffer containing the bytes of data may not be
    aligned.  This triggers expensive SIGBUS signal handling in
    the HP-UX PA-RISC operating system.
    .
    This APAR fixes the memory buffer misalignment involving the
    index key reads of UTF8 data.
    

Local fix

Problem summary

  • Users affected: All with unicode UTF8
                    codepage databases.
    Problem description: as above.
    Problem summary: This fix applies to
                     all OS platforms.
    

Problem conclusion

  • Problem was first fixed in Version 9.1 Fix Pack 4 (s071028).
    

Temporary fix

Comments

APAR Information

  • APAR number

    IY98624

  • Reported component name

    DB2 UDB ESE HP-

  • Reported component ID

    5765F4103

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-05-15

  • Closed date

    2007-11-23

  • Last modified date

    2009-01-21

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

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

    IY98644

Modules/Macros

  • ENGN_NLS
    

Fix information

  • Fixed component name

    DB2 UDB ESE HP-

  • Fixed component ID

    5765F4103

Applicable component levels

  • R910 PSN

       UP

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
07 January 2022