Q
Problem solve Get help with specific problems with your technologies, process and projects.

When are changes recorded in the database buffer cache?

An Oracle user asks about making changes in the database buffer cache.

Once we have the data in the Database buffer cache from datafiles, when are the changes (updates) made to the cache recorded in datafiles back? Is it periodic or at commit or at both? Is there a separate copy of Database buffer cache for each user?
At commit, the only requirement is that the change has to be written to the online redo log, by the LGWR (log writer) process.. It is not required that the change be written to the datafile. After some time (how long depends on the database activity), the DBWR (database writer) process will write changed, dirty blocks to the datafiles. This way, the database can update the datafiles in bulk fashion rather than with each and every commit. But your changes are guaranteed to be captured since they are written to the online redo logs.

There is only one buffer cache for all users.

This was last published in February 2008

Dig Deeper on Oracle database administration

PRO+

Content

Find more PRO+ content and other member only offers, here.

Have a question for an expert?

Please add a title for your question

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

SearchDataManagement

SearchBusinessAnalytics

SearchSAP

SearchSQLServer

TheServerSide.com

SearchDataCenter

SearchContentManagement

SearchFinancialApplications

Close