Top 10 Foreground Events by Total Wait Time

• Start here. It tells you what the database spent time waiting on.
• Events to watch:
  • db file sequential read or scattered read: I/O-bound
  • direct path read/write temp: spills to disk due to memory limits
  • enq: TX - row lock contention: blocking transactions
  • log file sync: commit contention
  • resmgr:cpu quantum: Resource Manager throttling (ADW)

Look at both total time and waits per second to distinguish chronic from bursty issues.