AI & BI differences

[durgaprasad1538]

Difference between AI&bi?why AI is optional area?
In which situation we have to use AI?

 

[RealHeavyDude]

Re: After image

Although the AI is optional, if your database contains any data of any value I strongly recommend you to use it. The AI contains information about all transaction successfully committed since the last backup was taken. Together with a good backup and the AI you are able to restore the database and roll it forward exactly to the point in time when the disaster happened.

Heavy Regards, RealHeavyDude.

 

[Rob Fitzpatrick]

Re: After image

I second that. Always use after-imaging on production databases, or wherever you have data you can't afford to lose. However it may not be essential for you if you have data that is generated, or can be re-created, or is unchanging, like in a test or development environment. In that case daily backups may be sufficient data-loss protection for you.

Also, where you use after-imaging I recommend using the AI File Management Daemon. It makes AI a little less painful to implement and eliminates the need to write scripts for switching AI extents. I also recommend that you use variable-size AI extents and do your extent switching based on time interval, rather than on the basis of filling a file of a given size. That way your window of potential data loss has a maximum size in terms of time (e.g. 15 minutes), which is important to the business side.

The before image file is not optional because it is central to database crash recovery, and also to the handling of database transactions. It contains information about uncommitted as well as committed transactions. The after image file only contains information about committed transactions, and its purpose is to mitigate data loss in the event of media failure or data loss due to human error. It is also an essential part of a disaster recovery plan for your production databases.

Read the Database Essentials and Database Administration manuals for information about the structures in an OpenEdge database, including BI and AI, and for general information on protecting your database data. You can also read Tom's presentation on after imaging.