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IT31485: CONTENTION ON SQLO_LT_SRVLST_CB__SRVLSTLATCHL LATCH DURING SSL CONNECTIONS

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APAR status

  • Closed as program error.

Error description

  • During SSL connections, there may be some contentions observed
    which are resulted from SQLO_LT_SRVLST_CB__srvLstLatchl latch
    waits.
    
    This latch is held during the reading for SSL port number entry
    in /etc/services file upon db2 database connection. And for any
    reason, the read I/O is taking long, and there is high
    concurrency in number of connections to the database, then
    longer latch waits on SQLO_LT_SRVLST_CB__srvLstLatchl can be
    observed, causing longer connection times.
    
    This defect will add an enhancement to not read SSL port number
    from /etc/services file upon each connection, but rather load it
    into the memory upon the first connection and be used by
    subsequent connections.
    
    db2pd -latches output collected during the issue, may show the
    following output:
    
    0x0780000000470D68 1183602    84416      sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    165652     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    155143     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    91878      sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    185478     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    286680     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    425941     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    269915     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    125267     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    128346     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    78456      sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    261764     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    289963     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    85535      sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    111414     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    175238     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    194977     sqleu_serverd.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    219593     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    0x0780000000470D68 1183602    245242     sqleu_server.C
    6329       SQLO_LT_SRVLST_CB__srvLstLatch 1
    

Local fix

  • As a temp workaround, SSL port number can be bumped up inside
    /etc/services file to help reads be faster.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All users on DB2 v111m4FP5 and earlier                       *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 v111m4FP6 or apply Local Fix is available     *
    ****************************************************************
    

Problem conclusion

  • First Fixed in DB2 v111m4FP6
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT31485

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-01-10

  • Closed date

    2021-03-15

  • Last modified date

    2021-03-15

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

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

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 PSY

       UP

  • RB50 PSY

       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":"11.1","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
04 May 2022