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Newbie:Why is select doing a table scan?

  • January 29, 2009 at 12:29 pm

    #934987

    ScottPletcher (1/29/2009)

    I never said it was doing a seek, I said it was using the index. It looked to me like SQL was scanning the non-clus index to get the key values to hash, rather than scanning the full table.

    Where do you see that? In the execution plan, the operator is Table Scan (ie scan of the heap), not Index Scan for all of the occurrences of sysValidationList. The nonclustered index isn't mentioned at all.

    The only index scans in the plan are against the Person table (using the pk_Person index) and the AssignmentDetails table (using the IX_AssignmentDetails index). Both are clustered index scans, so again a read of the entire table.

    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

  • January 29, 2009 at 1:13 pm

    #935019

    I was reading the textual plan, not the graphical one, which at a quick look I thought was using IX_sysValidationList index.

    SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.

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