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

What happens when we fire a DML statement?

I want to know when we fire a particular DML (delete) statement, what are the different activities that happen inside Oracle? For instance from user session to server session, then role of dbbuffer, redo buffer, and so on through redo log files and datafiles.

I want to know when we fire a particular DML (delete) statement, what are the different activities that happen inside Oracle? For instance from user session to server session, then role of dbbuffer, redo buffer, and so on through redo log files and datafiles.

When a DML operation occurs, Oracle first checks to ensure you have the appropriate permissions to perform this DML operaiton on this object. Assuming that you do, Oracle writes information to reverse the operation in the undo segments. Oracle also writes information to redo the operation in the Log Buffer. If you rollback the operation, the undo information is used to revert back to the time before the DML operation was started. If you commit the operation, Oracle flushes the information from the Log Buffer to the online redo log files. The commit is not complete until the information has been written to the online redo log files.

In the meantime, the data block containing the changed information is sitting in the Buffer Cache. This block is now considered "dirty" as its contents have changed. When Oracle performs a checkpoint, the dirty block is written to the tablespace's datafile.

Dig Deeper on Oracle database design and architecture

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.

Please create a username to comment.

-ADS BY GOOGLE

SearchDataManagement

SearchBusinessAnalytics

SearchSAP

SearchSQLServer

TheServerSide.com

SearchDataCenter

SearchContentManagement

SearchHRSoftware

Close