Using Continuous Operations
Continuous Operations provides the ability to backup data files while database applications are running and users are connected. However, in the event of a hard drive failure, if you use Continuous Operations to make backups, you will lose all changes to your data since the last backup. You cannot use Archival Logging and the Maintenance utility Roll Forward command to restore changes to your data files that occurred after the last backup.
PSQL provides a backup command, BUTIL, for Continuous Operations. (Note that PSQL also provides a product, Backup Agent, to set and manage continuous operations. See the documentation provided with that product, Backup Agent Guide, for details.)
*Note: A file put into continuous operations locks the data file from deletion through the Relational Engine and the MicroKernel Engine. In addition, the file is locked from any attempts to change the file structure, such as modifying keys and so forth.
This section is divided into the following sub-topics:
•
Starting and Ending Continuous Operations
•
Backing Up a Database with BUTIL
•
Restoring Data Files when Using Continuous Operations
Starting and Ending Continuous Operations
This section provides detailed information on the commands: Startbu and Endbu.
Table 30
Commands to Start and Stop Continuous Operation 
Command
Description
Startbu
Starts continuous operation on files defined for backup (BUTIL).
Endbu
Ends continuous operation on data files defined for backup. (BUTIL).
*Caution: The temporary delta files created by Continuous Operations mode have the same name as the corresponding data files but use the extension “.^^^” instead. No two files can share the same file name and differ only in their file name extension if both files are in the same directory. For example, do not use a naming scheme such as INVOICE.HDR and INVOICE.DET for your data files. If you do, the MicroKernel returns a status code and no files are put into Continuous Operations.
Continuous operation mode does not significantly affect MicroKernel performance; however, using a server to back up files can affect performance.
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To protect against data loss using Continuous Operation
1
Use the startbu command to put your files in continuous operation. See Startbu for an explanation of the command syntax with BUTIL.
2
Back up your data files.
3
Use the ENDBU command to take your files out of continuous operation. See Endbu for an explanation of the command syntax with BUTIL.
Backing Up a Database with BUTIL
This section provides detailed information on backing up a database using the following butil commands: Startbu and Endbu.
Startbu
The BUTIl startbu command places a file or set of files into continuous operation for backup purposes.
Format
BUTIL -startbu <sourceFile | @listFile> [/UID<name> </PWD<word>> [/DB<name>]]
sourceFile
The fully qualified name of the data file (including the drive specification for Windows platforms) on which to begin continuous operation for backup.
This fully qualified name must reside on the same machine as the one from which you are running butil. You cannot used mapped drives with the startbu command.
listFile
The name of a text file containing the fully qualified names of files on which to begin continuous operation. Separate these file names with a carriage return/line feed. The file names may contain blank characters.

If the Maintenance utility cannot put all of the specified files in continuous operation, the utility does not put any of the files in continuous operation.
/UID<name>
/UIDuname
Specifies the name of the user authorized to access a database with security enabled.
/PWD<word>
/PWDpword
Specifies the password for the user who is identified by uname. Pword must be supplied if uname is specified.
/DB<name>
/DBdbname
Specifies the name of the database on which security is enabled. If omitted, the default database is assumed.
*Note: The startbu command begins continuous operation only on the files you specify. You cannot use wildcard characters with the startbu command.

On Linux and OS X distributions, all slash (“/”) parameters use the hyphen (“-”) instead of the slash. For example, the /DB parameter is -DB.
File Considerations
When selecting files for backup, we recommend that the temporary delta files created by Continuous Operations mode be excluded since they are open and in use during backup. If the delta files are included in the backup, they should be deleted before the database engine is started after the restore.
Examples for Windows Server
Example A The first example starts continuous operation on the COURSE.MKD file.
For Windows Server:
butil -startbu file_path\PSQL\Demodata\course.mkd
(For default locations of PSQL files, see Where are the PSQL files installed? in Getting Started With PSQL.)
Example B The following example starts continuous operation on all files listed in the STARTLST.FIL file.
butil -startbu @startlst.fil
The STARTLST.FIL file might consist of the following entries:
file_path\PSQL\Demodata\course.mkd
file_path\PSQL\Demodata\tuition.mkd
file_path\PSQL\Demodata\dept.mkd
Endbu
The ENDBU command ends continuous operation on a data file or set of data files previously defined for backup. Issue this command after using the startbu command to begin continuous operation and after performing your backup.
Format
BUTIL -ENDBU </A | sourceFile | @listFile> [/UID<name> </PWD<word>> [/DB<name>]]
/A
If you specify /A, the utility stops continuous operation on all data files initialized by startbu and currently running in continuous operation mode.
sourceFile
The fully qualified name of the data file (including the drive specification for Windows platforms) for which to end continuous operation.
This fully qualified name must reside on the same machine as the one from which you are running butil. You cannot used mapped drives with the endbu command.
@listFile
The name of a text file containing a list of data files for which to end continuous operation. The text file must contain the fully qualified file name for each data file. Separate these file names with a carriage return/line feed. The file names may contain blank characters.

Typically, this list of data files is the same as the list used with the Startbu command.
/UID<name>
/UIDuname
Specifies the name of the user authorized to access a database with security enabled.
/PWD<word>
/PWDpword
Specifies the password for the user who is identified by uname. Pword must be supplied if uname is specified.
/DB<name>
/DBdbname
Specifies the name of the database on which security is enabled. If omitted, the default database is assumed.
*Note: On Linux and OS X distributions, all slash (“/”) parameters use the hyphen (“-”) instead of the slash. For example, the /A parameter for is -A, as in butil -endbu -A.
Example for Windows Server
The following example ends continuous operation on the COURSE.MKD file.
butil -endbu file_path\PSQL\Demodata\course.mkd
However, you can also just enter butil -endbu course.mkd instead of the full path if your current directory is f:\demodata.
Restoring Data Files when Using Continuous Operations
If you are using Continuous Operations for your backup strategy, then you have no recovery log that can be used to recover changes since your last backup. All database changes since your last backup are lost, with the possible exception of any transactions stored in the transaction log. Any such transactions are automatically rolled forward by the database engine when it starts up.
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To restore data and normal database operations
1
Resolve the failure.
Perform the maintenance required to make the failed computer operational again.
2
Restore the data files from backup, or restore the hard drive image from backup, as appropriate.
3
Reinstall PSQL if it was not restored as part of a disk image.
*Caution: If the delta files were included in the backup, they should be deleted before the database engine is started in the next step.
4
Re-start the database engine.
Any database operations performed since the last backup must be performed over again.