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 Online Logging 

Logging during normal database operation (online operational state) is called online logging. During online logging, the database system logs all modifying SQL statements of the transactions, meaning that log entries are written.

Online logging is subdivided as follows:

·        Redo Log Management

·        Undo Log Management

·        History Management (only for liveCache database instances)

Online logging has active components (tasks) and passive components (storage units.)

 

Active Components

Passive Components

Redo Log Management

User tasks that carry out transactions

Log writer

Log queue

Log area

Undo Log Management

User tasks

Undo log file

History Management

User tasks

Garbage collectors

History file

 

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