SQL Server System Databases
SQL Server System Databases
• Master
• Purpose – Core system database to manage the SQL Server instance. In SQL Server 2005, the Master database is the logical repository for the system objects residing in the sys schema. In SQL Server 2000 and previous editions of SQL Server, the Master database physically stored all of the system objects.
• Prominent Functionality
o Per instance configurations
o Databases residing on the instance
o Files for each database
o Logins
o Linked\Remote servers
o Endpoints
• Additional Information
o The first database in the SQL Server startup process
o In SQL Server 2005, needs to reside in the same directory as the Resource database
• Resource
• Purpose – The Resource database is responsible for physically storing all of the SQL Server 2005 system objects. This database has been created to improve the upgrade and rollback of SQL Server system objects with the ability to overwrite only this database.
• Prominent Functionality
o System object definition
• Additional Information
o Introduced in SQL Server 2005 to help manage the upgrade and rollback of system objects
o Prior to SQL Server 2005 the system related data was stored in the master database
o Read-only database that is not accessible via the SQL Server 2005 tool set
o The database ID for the Resource database is 32767
o The Resource database does not have an entry in master.sys.databases
• TempDB
• Purpose – Temporary database to store temporary tables (#temptable or ##temptale), table variables, cursors, work tables, row versioning, create or rebuild indexes sorted in TempDB, etc. Each time the SQL Server instance is restarted all objects in this database are destroyed, so permanent objects cannot be created in this database.
• Prominent Functionality
o Manage temporary objects listed in the purpose above
• Additional Information
o Each time a SQL Server instance is rebooted, the TempDB database is reset to its original state
• Model
• Purpose – Template database for all user defined databases
• Prominent Functionality
o Objects
o Columns
o Users
• Additional Information
o User defined tables, stored procedures, user defined data types, etc can be created in the Model database and will exist in all future user defined databases
o The database configurations such as the recovery model for the Model database are applied to future user defined databases
• MSDB
• Purpose – Primary database to manage the SQL Server Agent configurations
• Prominent Functionality
o SQL Server Agent Jobs, Operators and Alerts
o DTS Package storage in SQL Server 7.0 and 2000
o SSIS Package storage in SQL Server 2005
• Additional Information
o Provides some of the configurations for the SQL Server Agent service
o For the SQL Server 2005 Express edition installations, even though the SQL Server Agent service does not exist, the instance still has the MSDB database
• Distribution
• Purpose – Primary data to support SQL Server replication
• Prominent Functionality
o Database responsible for the replication meta data
o Supports the data for transaction replication between the publisher and subscriber(s)
• ReportServer
• Purpose – Primary database for Reporting Services to store the meta data and object definitions
• Prominent Functionality
o Reports security
o Job schedules and running jobs
o Report notifications
o Report execution history
• ReportServerTempDB
• Purpose – Temporary storage for Reporting Services
• Prominent Functionality
o Session information
o Cache