SQL Server Performance

using varchar

Discussion in 'Performance Tuning for DBAs' started by BikeBoy, Mar 17, 2007.

  1. BikeBoy New Member

    Some DBAs are insisting that VARCHAR is a no-no for small columns, while others say it matters not. Whanted to hear some opinions on that, what are the index implications, etc.

    Thanks
  2. ndinakar Member

    depends on a lot of factors. whats the nature of the data that goes in? is it all numbers/nulls? or would there be string values? If you have string values there's really not much debate. If the column is for values of states (in US) with values always being 2 characters like 'CA', 'AL'..etc its better to use CHAR(2). so no knowing what type of values goes in its hard for anyone here to pass opinions.

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    Dinakar Nethi
    SQL Server MVP
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  3. FrankKalis Moderator

    I guess one argument in this discussion might be, that each VARCHAR column has an overhead of 2 bytes in the column offset array. So, if such data does not vary greatly in length, it could be worth investigating such a CHAR without an entry in the column offset array to "save" these 2 bytes. Will that make however the distinction between a good and a bad performing system? I seriously doubt that.

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    Frank Kalis
    Moderator
    Microsoft SQL Server MVP
    Webmaster:http://www.insidesql.de

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