xSQL filebackup

Perform a file backup for a persistent database.

For an overview see page File_Backup

Prototype

     
    XSQL>filebackup dbFile logFile [nThreads]
     

Arguments

dbFile The path and filename for the backup database file
logFile The path and filename for the backup log file
nThreads The number of threads to perform the file copy operation

Description

This command copies the database and log file for a persistent database. The database can then be "restored" by simply specifying these backup files when opening the database in the normal way.

Note that the SQL file backup temporarily prevents the truncation of the database log file, then copies the database and log files using one or more threads. Note the following:

1. The database can be changed while the file backup is in progress

2. The file backup method only works with REDO logging policy and will return an error if using UNDO log or if there is no transaction log

3. The SQL file backup does not support either multi-storage or mfd databases. The backup process makes copies only of a single database and log files passed into the API

The advantage of using this backup method over the Incremental backup is that it could be faster and no restore procedures are necessary; applications simply open the backup database.

The file_backup_delay config file parameter can be adjusted to specify the delay in milliseconds between writing backup blocks in order to minimize backup impact on performance.

(See also C API mco_disk_backup().)

Example

 
    XSQL>filebackup SimpleDb_backup.dbs SimpleDb_backup.log 1