what is instance recovery

[SBALAJIKUM]

Hey guys,

Can any one brief about what is instance recovery.

[tomate]

Hi
is your database is broken and you have save your db then you can bring your db to old condition.
It is a backup mechanisum.

[Chris]

Hi,

check the section on "Recovery from Instance failure" in Oracle Concepts. it explains it fairly well.

cheers

chris.

[kmesser]

Oracle instance = memory structures and background processes which are necessary to access the data in an Oracle database.

Instance failure essentially means that some software or hardware failure is preventing these software systems from functioning as designed. An instance failure could be caused by an operating system crash or lockup.

When the instance fails, some transactions could be incomplete. That is, some changes could have been made to the database and recorded in the redo logs, but have not been committed. If that is the case, when the database is restarted, all transactions in the redo logs will be applied to the database whether they are committed or not. Once all these changes are applied, the database can open. Upon opening, the database will begin rolling back any of those changes which are not committed. The rollback can be initiated by background processes automatically or as a result of a user attempt to access this uncommitted data.

[SBALAJIKUM]

THANX GUYS.