SQL SERVER LOCKING ISSUES

  • I found a blocking issues using the DMV .

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    from the captured result . I use DBCC IND('DBNAME', 'M_SYSTEM_CONFIG',-1), but i did not see the page number 1:1009316

    I use dbcc PAGE (DBNAME, 1 , 1009316 ,3) WITH TABLERESULTS , it show me that the page Metadata: IndexId1 and Metadata: ObjectId 645577338 . number 645577338 is the object id for table m_system_config . DBCC CHEDKDB show zero consistency error .

    Is these normal to the database ? can someone explain how should i proceed to troubleshoot this blocking ? the only 2 statament that involve in table M_SYSTEM_CONFIG while blocking is update and select from a different rows . only 17 rows is in the table . i do not know select will trigger an exclusive lock .

  • Setup a server side trace to identity what is causing the blocking. There are groups available for blocking in SQLserver. Hope this helps you to identify the blocking.

    -- Babu

  • Unfortunately , the blocking happened again . and blocked process report capture nothing . I run the SOL SEVER report- activity -all blocking transaction during the blocking to show the blocking transaction .

    blocking statement

    key 59 --

    key 51 update M_SYSTEM_CONFIG set sys_value = sys_value +1 where Getdate() > eff_start_dt and sys_key= 'LAST_USED_LOG_ID'

    what kind of blocking is not able to trace by the profiler ? and why sql server showing -- in the blocking statement ?

  • The blocking occur intermittent

    i have also set sp_configure 'blocked process threshold', 10. .

    and when the blocking happened , i try to select other rows in the config table , it return the result .

    But when i try to select the row which condition where Getdate() > eff_start_dt and sys_key= 'LAST_USED_LOG_ID' , it will keep loading because these particular key was blocked by the update statement .

    But what have cause the blocked for these update statement ? I can see exclusive lock . but there are no other insert or update to the config table except the only one which blocked .

  • http://www.simple-talk.com/books/sql-books/troubleshooting-sql-server-a-guide-for-the-accidental-dba/ Chapter 6.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • If the process is coming from another server, such as a LinkedServer query it can be trickier to figure out.

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