Why is SQL Monitor so great?
In days long past the best tool for tuning SQL was the humble 10046 trace, and it’s still useful today, but other tools have been developed over the years, to give us the high level picture with some deep dives when needed. Not least of which is SQLTXPLAIN. SQL Monitor has been around for a while but in 12c it has been improved and is now especially useful for parallel execution.
10046 is useful because it tells us what has actually happened. Not what we think is going to happen. The same applies to SQL Monitor. ...
