Empty sys.dm_db_missing_index_group_stats

  • Hi,

    we have a production server (SQL Server 2005). What can be the reason why this table is empty after a certain time?

    SELECT *

    FROM sys.dm_db_missing_index_group_stats

    --0 Rows--

    There is a lot of traffic on this Server / Database. Can it be that a table overflows?

    Regards

    Nicole

  • Congratulations! You have no missing indexes !

    But if seriously, do you have "view server state" or higher permissions?

  • yes, SysAdmin 🙂

  • Was your instance restarted recently?

    Was it started from DOS-prompt with -x argument?

  • No, the Instanz/Server startet 1 Time in Month (in know, the table after a reboot is empty) ; I think there are running to much Inserts in any System-Table and then SqlServer becomes an overflow...

  • info 58414 (6/5/2014)


    I think there are running to much Inserts in any System-Table and then SqlServer becomes an overflow...

    Even if would be really the case, SQL Server would leave at least SOME records there. This is not a table, this is a view that based on some internal memory structures, so there is no way to truncate it while server is running.

    I would suggest to make some test:

    1. Create a dummy table with 2+ columns and one of them is unique

    2. Populate it with million records. Don't create any index on it.

    3. Run some select on it where your_column_name = some number. So it must return only one record.

    4. Check execution plan. SQL Server will display index recommendation.

    5. Check missing indexes DMV.

  • It's also theoretically possible that the feature has been disabled by starting SQL with a "-x" switch. Not likely, but possible :-).

    SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

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