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IC80783: DATABASE MAY HANG DUE TO SMALL TIMING HOLE WHEN TERMINATING AGENT SIGNALS LOGGER TO FLUSH THE TRANSACTION BUFFER

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APAR status

  • Closed as program error.

Error description

  • There is a small timing hole that can cause a database hang.
    When a terminating agent may need to have the transaction log
    buffer flushed, it posts a message to the db2loggr agent.  In
    rare cases, if the db2loggr is responding to other posts at the
    same time, the post from the terminating agent may get lost.
    
    
    The db2agent would have the following stack, where it is waiting
    for a response from the db2loggr thread.  This agent would be
    holding the database latch during this time, which will cause
    other agents waiting for the latch to wait.
    
    sqloWaitEDUWaitPost
    sqlpgPostLoggrWithoutLatching
    sqlpterm
    sqeLocalDatabase::CleanDB
    sqeLocalDatabase::TermDbConnect
    sqeApplication::AppStopUsing
    sqlesrspWrp
    sqleUCagentConnectReset
    sqljsCleanup
    sqljsDrdaAsInnerDriver
    sqljsDrdaAsDriver
    sqeAgent6RunEDU
    sqlzRunEDU
    
    
    
    The db2loggr thread, not seeing a waiting action would then go
    to sleep waiting for more work:
    
    sqloWaitEDUWaitPost
    sqlpgasnPcj
    sqloEDUEntry
    

Local fix

  • None, though the chance to hit the timing hole is small.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All DB2 users                                                *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.7 Fix Pack 7 or higher              *
    ****************************************************************
    

Problem conclusion

  • Problem first fixed in DB2 Version 9.7 Fix Pack 7
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC80783

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-01-11

  • Closed date

    2012-10-31

  • Last modified date

    2012-10-31

  • 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

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC80783

Modified date: 31 October 2012