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Re: Does insert operation in table uses rollback segment [message #56512 is a reply to message #56505] |
Fri, 04 April 2003 07:54 |
Anand
Messages: 161 Registered: August 1999
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Senior Member |
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Whenever you do any DML operation ( INSERT, UPDATE , DELETE), Oracle takes an image/copy of the old data and stores in the rollback segments. That what rollback segments are used for. So, when you try to INSERT new data, old data goes to the rollback segment. Once you COMMIt the changes, new data is written permanently to the table and old data is discarded. However, the data in the rollback segments are not automatically flushed out. When a new transaction requests space in the rollback segments, old data are automatically flushed out of the rollback segments.
Incase you do a ROLLBACK, the old data is copied back from the rollback segments to the data blocks and the new data is discarded.
Whenever you INSERT, DELETE or UPDATE, old data will be stored in the rollback segments.
Hope it's clear.
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