Updating millions of records in oracle
I have oracle 11 g R1 I am sure many of us must have gone through this situation.
You will bypass all UNDO generation with DDL and have the opportunity, if appropriate, to skip REDO generation as well (by using NOLOGGING).
At the very least, you will minimize the amount of REDO you generate.
Since my table is 10x that size, that method may not be an improvement.
If you're on 11g, drop the column and add it back as a NOT NULL column with a default value.
I need to update the table A with only 2 columns from the table B. This can be slow, and update is a slow enough operation anyway.