buffer cache and Rollback

Giganews Newsgroups
Subject: buffer cache and Rollback
Posted by:  plbiā€¦@gmail.com
Date: Fri, 27 Jul 2007

Question:

During updating any table, it updates the block in the buffercache and
not the actual datafile. In a scenerio where the user executes the
update and don't commit, Does the select query of other users will be
retreived from the rollback segment(data file) or from the same
datablock which is cached in the buffer cache.How does it work. During
any updates does it copy the old image to the rollback
segment(datafile), if so any update it requires disk access... please
clarify...

Thanks

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