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When any transactions takes place in Oracle it writes the whole activity or to say the transaction to a log file.
This information is written in two log files mainly redo and undo. Redo log file is used for applying the changes
in the database from a particular point of time in case of recovery. whereas undo logfile is used when u have to rollback some transaction.
There are 4 files called as online redolog files which contain the changes made in oracle. But these file have a size
limit so when this gets filled up this is written to a offline file called as offline redolog file, also when the database reaches
checkpoint even then all the contents in the online redolog file is written to offline and the online file is ready for overwriting of data.
When any transactions takes place in Oracle it writes the whole activity or to say the transaction to a log file.
This information is written in two log files mainly redo and undo. Redo log file is used for applying the changes
in the database from a particular point of time in case of recovery. whereas undo logfile is used when u have to rollback some transaction.
There are 4 files called as online redolog files which contain the changes made in oracle. But these file have a size
limit so when this gets filled up this is written to a offline file called as offline redolog file, also when the database reaches
checkpoint even then all the contents in the online redolog file is written to offline and the online file is ready for overwriting of data.
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