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.

Pervasive PSQL provides a backup command, BUTIL, for Continuous Operations.

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Note
A file put into continuous operations locks the data file from deletion through the relational interface and the transactional interface. In addition, the file is locked from any attempts to change the file structure, such as modifying keys and so forth.

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This section is divided into the following sub-topics:

Starting and Ending Continuous Operations

This section provides detailed information on the commands: STARTBU and ENDBU.

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Note
The temporary delta files created by Continuous Operations mode have the same name as the corresponding data files but use the extension ".^^^" instead. Therefore, in the same directory, do not create multiple data files with the same names but different extensions. 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 status 85 and no files will be put in Continuous Operations.

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Continuous operation mode does not significantly affect MicroKernel performance; however, using a server to back up files can affect performance.

To protect against data loss using Continuous Operation

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>]]

 
 


 Note


This command begins continuous operation only on the files you specify. You cannot use wildcard characters with the STARTBU command.

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 Pervasive PSQL files, see Where are the Pervasive PSQL v10 files installed? in Getting Started With Pervasive 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>]]

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.

To restore data and normal database operations