Home Forums SQL Server 2016 SQL Server 2016 - Development and T-SQL Indexes RE: Indexes

  • January 23, 2017 at 3:24 am

    #1924346

    Welsh Corgi - Monday, January 23, 2017 2:58 AM

    So are you telling me if a have for example an index CallID as a single column index and I have another Index that starts off with CallID and several other columns I do not need the index with CallID as the single column Index?

    In general, yes. The narrower index is redundant.

    John Mitchell-245523 - Monday, January 23, 2017 3:20 AM

    Have you looked in sys.dm_db_index_usage_stats?

    Index usage stats will usually show both indexes being used, because the optimiser will happily use them both (also happens when there are multiple identical indexes)

    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

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