Backup and restore history details

原文地址：http://www.sqlbackuprestore.com/backuprestorehistorytables.htm

SQL Server maintains a set of tables in the msdb database, that stores details of all backups and restores that have been performed. Even if you are using a 3rd party backup application, the details are stored if the applications use the SQL Server Virtual Device Interface (VDI) to perform the backups and restores.

The tables that store the details are:

·

backupset

·

backupfile

·

backupfilegroup (SQL Server 2005 upwards)

·

backupmediaset

·

backupmediafamily

·

restorehistory

·

restorefile

·

restorefilegroup

·

logmarkhistory

·

suspect_pages (SQL Server 2005 upwards)

You can find out more about each table from Books Online.

Here's a script to find out the most recent backups for each database.

SELECT b.name, a.type, MAX(a.backup_finish_date) lastbackup FROM msdb..backupset a INNER JOIN master..sysdatabases b ON a.database_name COLLATE DATABASE_DEFAULT = b.name COLLATE DATABASE_DEFAULT GROUP BY b.name, a.type ORDER BY b.name, a.type

Another situation I find myself having to query these tables is when my log shipping breaks on the secondary server due to an out-of-sequence log. I could run something like this to find out the last 10 transaction log backups for a particular database:

SELECT TOP 20 b.physical_device_name, a.backup_start_date, a.first_lsn, a.user_name FROM msdb..backupset a INNER JOIN msdb..backupmediafamily b ON a.media_set_id = b.media_set_id WHERE a.type = 'L' ORDER BY a.backup_finish_date DESC

The physical_device_name tells me which file I will need to continue the transaction log restore sequence, using the first_lsn value as a reference (the value that the secondary server requires to continue restoring the transaciton logs). The user_name tells me who I need to have some serious words with!

Or say I need to restore an entire sequence of transaction logs created after 10-Jan-2008, up to a point in time on 16-Jan-2008 3:30 AM. I could use the following query to display the files I need to restore in sequence:

SELECT b.physical_device_name, a.backup_set_id, b.family_sequence_number, a.position, a.backup_start_date, a.backup_finish_date FROM msdb..backupset a INNER JOIN msdb..backupmediafamily b ON a.media_set_id = b.media_set_id WHERE a.database_name = 'AdventureWorks' AND a.type = 'L' AND a.backup_start_date > '10-Jan-2007' AND a.backup_finish_date < '16-Jan-2009 3:30' ORDER BY a.backup_start_date, b.family_sequence_number

The family_sequence_number tells me how may files are containined in each backup set, and position tells me which backup set in a file I need to use, when the backup file contains multiple backup sets.

Now, these tables can grow pretty large over time. SQL Server provides the sp_delete_backuphistory stored procedure to delete historical data. E.g.

EXEC msdb..sp_delete_backuphistory '1-Jan-2005'

deletes all details of backup and restore processes created before January 1 2005. Note that this stored procedure exists in the msdb database, not the master database.

NOTE: In SQL Server 2000, the performance of this stored procedure is pretty dismal when deleting large number of records, due to the use of cursors. Here's a stored procedure you can try, adapted from a forum post on sqlteam.com, that does not use cursors: CREATE PROC sp_delete_backuphistory_alt    (@DaysToRetain INT) AS SET NOCOUNT ON DECLARE   @intErrNo int DECLARE @dtCutoff datetime BEGIN TRANSACTION DeleteBackupHistory    DELETE FROM msdb..restorefile    FROM msdb..restorefile rf    INNER JOIN msdb..restorehistory rh ON rf.restore_history_id = rh.restore_history_id    INNER JOIN msdb..backupset bs on rh.backup_set_id = bs.backup_set_id    WHERE bs.backup_finish_date < (GETDATE() - @DaysToRetain)    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL    DELETE FROM msdb..restorefilegroup    FROM msdb..restorefilegroup rfg    INNER JOIN msdb..restorehistory rh ON rfg.restore_history_id = rh.restore_history_id    INNER JOIN msdb..backupset bs on rh.backup_set_id = bs.backup_set_id    WHERE bs.backup_finish_date < (GETDATE() - @DaysToRetain)    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL        DELETE FROM msdb..restorehistory    FROM msdb..restorehistory rh    INNER JOIN msdb..backupset bs on rh.backup_set_id = bs.backup_set_id    WHERE bs.backup_finish_date < (GETDATE() - @DaysToRetain)    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL        SELECT media_set_id, backup_finish_date    INTO #Temp    FROM msdb..backupset bs    WHERE backup_finish_date < (GETDATE() - @DaysToRetain)    AND NOT EXISTS    (SELECT bs2.media_set_id FROM msdb..backupset bs2    WHERE bs.media_set_id = bs2.media_set_id AND bs2.backup_finish_date > @dtCutoff)    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL        DELETE FROM msdb..backupfile    FROM msdb..backupfile bf    INNER JOIN msdb..backupset bs on bf.backup_set_id = bs.backup_set_id    INNER JOIN #Temp t ON bs.media_set_id = t.media_set_id    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL    DELETE FROM msdb..backupset    FROM   msdb..backupset bs    INNER JOIN #Temp t ON bs.media_set_id = t.media_set_id    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL        DELETE FROM msdb..backupmediafamily    FROM msdb..backupmediafamily bmf    INNER JOIN msdb..backupmediaset bms ON bmf.media_set_id = bms.media_set_id    INNER JOIN #Temp t ON bms.media_set_id = t.media_set_id    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL        DELETE FROM msdb..backupmediaset    FROM msdb..backupmediaset bms    INNER JOIN #Temp t ON bms.media_set_id = t.media_set_id    SELECT   @intErrNo = @@ERROR    IF @intErrNo <> 0 GOTO AbortSQL AbortSQL:    IF @intErrNo <> 0    BEGIN       ROLLBACK    END    ELSE    BEGIN       COMMIT TRANSACTION SQBDeleteBackupHistory    END    DROP TABLE #Temp ExitSQL:    SET NOCOUNT OFF Another suggestion to speed up the deletion is to create an index on the media_set_id column in the backupset table. However, modifying system tables should always be done with caution.