Finding user tables in SQL Server system databases

User tables in sys DBs

Why should you care about them?

User data tables should not be in the system databases (master, msdb).

In case of failure, there is a high chance that those tables would be lost.

In the case of migration, these tables may be forgotten and not restored.

It shows that some users may have excessive access rights to system databases.

Also, maybe someone is running a query or pointing third party tool at the wrong database, deploying some objects, and not cleaning up after.

By the way, this check is a part of our SQL Server Health Check service.

How can you find user-created tables in the SQL Server system databases?

You can use the script below to list all user tables in master and msdb databases.

  2. 'msdb' AS SysDatabaseName ,
  3. name AS UserTable
  4. FROM    msdb.sys.tables
  5. WHERE   is_ms_shipped = 0
  6. AND name NOT LIKE '%DTA_%'
  7. UNION
  8. SELECT 
  9. 'model' AS SysDatabaseName ,
  10. name AS UserTable
  11. FROM    model.sys.tables
  12. WHERE   is_ms_shipped = 0;

How to fix them?

  1. Rename tables. If no problems after X (30?) days, delete them.
  2. It could also fix security, so this can’t happen again.
  3. Ideally, you want to add automated DDL (any object modifications) monitoring to log all.

More information

Microsoft – msdb database.
Microsoft- model database.

Mark Varnas

Mark Varnas

Hey I'm Mark, one of the guys behind Red9. I make a living performance tuning SQL Servers and making them more stable. I channel my SQL into our SQL Managed Services, SQL Consulting and our internal database products.

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