Start Here: Performance Triage

Use this decision tree to get oriented quickly:

Is the problem with one query or the whole system?

• One query is slow
  • Capture the SQL_ID
  • View the execution plan
  • Look for bad access paths, joins, temp usage
  • See: Diagnosing a Slow Query
• Multiple queries are slow
  • Check system resource usage (CPU, I/O, concurrency)
  • Identify heavy queries in AWR or SQL Monitor
  • See: Diagnosing System-Wide Performance Issues
• Query performance regressed recently
  • Check plan history (DBA_HIST_SQL_PLAN)
  • See if optimizer stats changed or binds differ
  • See: Understanding Plan Instability