SQL Server Database States and Switch Paths


  • Database States
      A database is always in one specific state. For example, these states include ONLINE, OFFLINE, or SUSPECT. To verify the current state of a database, select the state_desc column in the sys.databases catalog view or the Status property in the DATABASEPROPERTYEX function.
  • Database State Definitions
     The following table defines the database states.    
State
Definition
ONLINE
Database is available for access. The primary filegroup is online, although the undo phase of recovery may not have been completed.
-- Make the Database Online
ALTER DATABASE [myDB] SET ONLINE WITH ROLLBACK IMMEDIATE 
OFFLINE
Database is unavailable. A database becomes offline by explicit user action and remains offline until additional user action is taken. For example, the database may be taken offline in order to move a file to a new disk. The database is then brought back online after the move has been completed.
-- Take the Database Offline
ALTER DATABASE [myDB] SET OFFLINE WITH
ROLLBACK IMMEDIATE | ROLLBACK AFTER integer [ SECONDS ] | NO_WAIT
RESTORING
One or more files of the primary filegroup are being restored, or one or more secondary files are being restored offline. The database is unavailable.
RECOVERING
Database is being recovered. The recovering process is a transient state; the database will automatically become online if the recovery succeeds. If the recovery fails, the database will become suspect. The database is unavailable.
RECOVERY PENDING
SQL Server has encountered a resource-related error during recovery. The database is not damaged, but files may be missing or system resource limitations may be preventing it from starting. The database is unavailable. Additional action by the user is required to resolve the error and let the recovery process be completed.
SUSPECT
At least the primary filegroup is suspect and may be damaged. The database cannot be recovered during startup of SQL Server. The database is unavailable. Additional action by the user is required to resolve the problem.
EMERGENCY
User has changed the database and set the status to EMERGENCY. The database is in single-user mode and may be repaired or restored. The database is marked READ_ONLY, logging is disabled, and access is limited to members of the sysadmin fixed server role. EMERGENCY is primarily used for troubleshooting purposes. For example, a database marked as suspect can be set to the EMERGENCY state. This could permit the system administrator read-only access to the database. Only members of the sysadmin fixed server role can set a database to the EMERGENCY state.






























  • Relationships of Database States