RESTORE statement

Description

Restores a Sybase IQ database backup from one or more archive devices.

Syntax

RESTORE DATABASE 'db_file'
FROM 'archive_device' [ FROM 'archive_device' ]... 
...[KEY key_spec]
... [ RENAME dbspace-name TO 'new-dbspace-path']...
... [ CATALOG ONLY ]

Parameters

db_file:

Relative or absolute path of the database to be restored. Can be the original location, or a new location for the Catalog Store file.

key_spec:

Quoted string including mixed cases, numbers, letters, and special characters. It might be necessary to protect the key from interpretation or alteration by the command shell.

Examples

Example 1

Usage

The RESTORE command requires exclusive access by the DBA to the database. This exclusive access is achieved by setting the -gd switch to DBA, which is the default when you start the server engine. Issue the RESTORE command before you start the database (you must be connected to the utility_db database). Once you finish specifying RESTORE commands for the type of backup, that database is ready to be used. The database is left in the state that existed at the end of the first implicit CHECKPOINT of the last backup you restored. You can now specify a START DATABASE to allow other users to access the restored database.

NoteYou can restore only databases created using Sybase IQ 12.4.3 and higher. If the database was created using a 12.x version prior to 12.4.3, you must upgrade it to 12.4.3 or greater before backup. For instructions, see the Sybase IQ Installation and Configuration Guidefor the version to which you are upgrading.

When restoring to a raw device, make sure the device is large enough to hold the dbspace you are restoring. IQ RESTORE checks the raw device size and returns an error, if the raw device is not large enough to restore the dbspace. For more information, see “Restoring to a raw device” in Chapter 14, “Data Backup, Recovery, and Archiving” in the Sybase IQ System Administration Guide.

BACKUP allows you to specify full or incremental backups. You can choose two kinds of incremental backups. INCREMENTAL backs up only those blocks that have changed and committed since the last backup of any type (incremental or full). INCREMENTAL SINCE FULL backs up all the blocks that have changed since the last full backup. If a RESTORE of a full backup is followed by one or more incremental backups (of either type), no modifications to the database are allowed between successive RESTORE commands. This rule prevents a RESTORE from incremental backups on a database in need of crash recovery, or one that has been modified. You can still overwrite such a database with a RESTORE from a full backup.

Before starting a full restore, you must delete two files: the Catalog Store file (default name dbname.db) and the transaction log file (default name dbname.log).

If you restore an incremental backup, RESTORE ensures that backup media sets are accessed in the proper order. This order restores the last full backup tape set first, then the first incremental backup tape set, then the next most recent set, and so forth, until the most recent incremental backup tape set. If the DBA produced an INCREMENTAL SINCE FULL backup, only the full backup tape set and the most recent INCREMENTAL SINCE FULL backup tape set is required; however, if there is an INCREMENTAL made since the INCREMENTAL SINCE FULL, it also must be applied.

Sybase IQ ensures that the restoration order is appropriate, or it displays an error. Any other errors that occur during the restore results in the database being marked corrupt and unusable. To clean up a corrupt database, do a RESTORE from a full backup, followed by any additional incremental backups. Since the corruption probably happened with one of those backups, you might need to ignore a later backup set and use an earlier set.

FROM Specifies the name of the archive_device from which you are restoring, delimited with single quotation marks. If you are using multiple archive devices, specify them using separate FROM clauses. A comma-separated list is not allowed. Archive devices must be distinct. The number of FROM clauses determines the amount of parallelism Sybase IQ attempts with regard to input devices.

The backup/restore API DLL implementation lets you specify arguments to pass to the DLL when opening an archive device. For third-party implementations, the archive_device string has the following format:

'DLLidentifier::vendor_specific_information'

A specific example is:

'spsc::workorder=12;volname=ASD002'

The archive_device string length can be up to 1023 bytes. The DLLidentifier portion must be 1 to 30 bytes in length and can contain only alphanumeric and underscore characters. The vendor_specific_information portion of the string is passed to the third-party implementation without checking its contents.

NoteOnly certain third-party products are certified with Sybase IQ using this syntax. See the Sybase IQ Release Bulletin for additional usage instructions or restrictions. Before using any third-party product to back up your Sybase IQ database, make sure it is certified. See the Sybase IQ Release Bulletin, or see the Sybase Certification Reports for the Sybase IQ product in Technical Documents.

For the Sybase implementation of the backup/restore API, you need not specify information other than the tape device name or file name. However, if you use disk devices, you must specify the same number of archive devices on the RESTORE as given on the backup; otherwise, you may have a different number of restoration devices than the number used to perform the backup. A specific example of an archive device for the Sybase API DLL that specifies a nonrewinding tape device for a UNIX system is:

'/dev/rmt/0n'

RENAME Lets you restore one or more Sybase IQ database files to a new location. Specify each dbspace-name you are moving as it appears in the SYSFILE table. Specify new-dbspace-path as the new raw partition, or the new full or relative path name, for that dbspace.

If relative paths were used to create the database files, the files are restored by default relative to the Catalog Store file (the SYSTEM dbspace), and a rename clause is not required. If absolute paths were used to create the database files and a rename clause is not specified for a file, it is restored to its original location.

Relative path names in the RENAME clause work as they do when you create a database or dbspace: the main IQ Store dbspace, Temporary Store dbspaces, and Message Log are restored relative to the location of db_file (the Catalog Store); user-created IQ Store dbspaces are restored relative to the directory that holds the main IQ dbspace.

Do not use the RENAME clause to move the SYSTEM dbspace, which holds the Catalog Store. To move the Catalog Store, and any files created relative to it and not specified in a RENAME clause, specify a new location in the db_file parameter.

CATALOG ONLY Restores only the backup header record from the archive media.

Other RESTORE issues:

The maximum size for a complete RESTORE command, including all clauses, is 32KB.


Side effects

None.

Standards

Permissions

Must have DBA authority.

See also

BACKUP statement