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sparse column - how it works

  • January 24, 2011 at 6:21 am

    #233213

    I have read few articles on sparse columns.

    I found that when you store null values in sparse columns it wont need any storage space and when you store non null in any sparse column , it would need additional 4 byte

    Can anyone tell me WHY?

    May be something related to bitmap but want to know more .

    if anyone has the answer please let me know

  • October 7, 2013 at 4:13 pm

    #1656560

    Google "SQL Server Sparse Vector" to get the full details. The Sparse Vector tracks the storage of sparse columns. In the Sparse Vector (among other things) is two bytes that stores the column ID of any sparse column that isn't null. There is another two bytes that stores the offset to the end of the sparse data.

    Bob McC

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