From the course: Oracle Database 12c: Administration

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Redo log files

Redo log files - Oracle Database Tutorial

From the course: Oracle Database 12c: Administration

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Redo log files

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- [Instructor] The Redo Log Files store database change vectors, which are events that represent modifications done to database rows and the database table structure. These Redo records are mainly used by the Oracle Instance for crash recovery purposes. Redo Logs are the Oracle name for the database transaction log. If you lose your database Redo Log Files, you lose your database, and won't be able to start it up. The Oracle database requires at least two Redo Log Files at any given time, as it writes to them in a cyclic manner. Meaning, that the database writes to the first Redo Log File, and once that Redo Log File is filled up, the database will start writing to the second Redo Log File. This is called a Redo Log switch. Once the second Redo Log File was written to, and is now full, the database returns and writes back to the first one, and vice versa. That's why it's called a cyclic write. While two is the minimum amount of Redo Logs an Oracle database requires, we can, and often…

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