I attended a session in Oracle Open World 2016 given by Kyle Hailey.
In his presentation Kyle talked about how to measure database performance and what to look for when application is running slow.
I am sharing few notes from his session:
- Counting is the key to v$active_session_history.
DB Time ~= count(*)
Average Active Session (AAS) = DB Time / elapsed
- AAS Formulas
AAS < 1 : Database is not blocked
AAS ~= 0 : Database basically idle
AAS < # of CPUs : CPU available
AAS > # of CPUs : Could have performance problems
AAS >> # of CPUS : There is a bottleneck
Kyle provided following github link for all his scripts.
This is the presentation given by him.