Regarding redo log writes, does Oracle filter out all null columns for an INSERT statement and just write the minimal...
set of columns that have data to the redo log even when a column is explicitly set to null? I ask this because we are seeing an order of magnitude log writing over increasing size of the database when most of the activity is inserting.
Yes, Oracle does filter out the NULL columns in an INSERT statement. To verify, one needs to run Log Miner to mine some INSERT commands from the archived redo logs. If you do that, you will see that Oracle will have transformed your INSERT statement into one that specifically denotes the columns receiving the new values.
Have a question for Brian Peasland? Send an e-mail to firstname.lastname@example.org
Dig Deeper on Oracle database design and architecture
Related Q&A from Brian Peasland
Oracle expert Brian Peasland answers one reader's question about common pitfalls when connecting Oracle to outside programs.continue reading
One reader asks expert Brian Peasland a question about datafile sizes with the Oracle RMAN duplicate 10g command.continue reading
Managing parent table-child table relations in Oracle SQL environments is key to efficient programming.continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.