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Clustered Index SEEK as the highest cost in a query plan

  • February 19, 2014 at 6:18 am

    #288252

    Hi All,

    In a query i've been investigating, i made a change such that now the most expensive part of the query is a CLUSTERED INDEX SEEK (93%).

    i need help on this 2 areas:

    1. how to reduce this CLUSTERED INDEX SEEK cost ?

    2. how to avoid KEE LOCKUP on CLUSTERED INDEX SEEK ?

    THanks

    bhanu

  • February 19, 2014 at 6:25 am

    #1690234

    Firstly, is the cost a problem? Large is not necessarily a problem as the percentages within a plan have to add to 100%

    You'll never see a key lookup caused by a clustered index seek. Key lookups occur when a seek/scan is done of a nonclustered index and SQL needs to fetch additional columns from the clustered index/heap.

    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

  • February 19, 2014 at 7:21 am

    #1690252

    Gila is right on both fronts, key lookups only occur in that situation and all execution plans add up to 100%

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