Data visualization is a useful method to identify performance patterns. In most cases, I pull custom performance metrics from AWR repository and use tableau to visualize the data. Of course, you can do the visualization using excel spreadsheet too.
Problem definition
We had huge amount of PX qref waits in a database:
Tota Wait % DB Event Waits Time Avg(ms) time Wait Class ------------------------------ ------------ ---- ------- ------ ---------- PX qref latch 63,669,198 3341 0 34.2 Other DB CPU 3031 31.1 direct path read temp 92,996 199. 2 2.0 User I/O direct path write temp 12,029 109. 9 1.1 User I/O direct path read 5,454 61.1 11 .6 User I/O