How can identify those indexes which are slow down database performance.

  • Identify those indexes which are slow down database performance.

     

  • A few things to look out for:
    - Indexes that are never used for seeks or scans
    - Indexes that are too wide (have more columns than are necessary to satisfy a query)
    - Indexes that are duplicates, or subsets, of other indexes
    - Lack, or inappropriate choice, of clustered index

    This is a big topic - far too much for a forum post.  Some of it comes down to experience.  Other things can be identified using DMVs and catalog views.  What is the context of your question - do you suspect you have "bad" indexes?

    John

  • Hi John,
    Thanks for your response.
    I want to identify all Indexes which are "Incorrect" and slow down  database/  query performance.

  • Indexes don't slow down query performance though. And what exactly do you define as an 'incorrect' index?

    Technically all indexes will slow down data changes (inserts), but that's usually not a problem.

    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
  • Try using the following tables to extract info.
    sys.indexes
    sys.dm_db_index_usage_stats
    sys.dm_db_index_physical_stats

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