You notice performance degradation in your production Oracle 12c database. You want to know what caused this performance difference. Which method or feature should you use?

Question

Options

• ADatabase Replay
• BAutomatic Database Diagnostic Monitor (ADDM) Compare Period report
• CActive Session History (ASH) report
• DSQL Performance Analyzer

• A
  8% (4)
• B
  74% (39)
• C
  15% (8)
• D
  4% (2)

Explanation

ADDM Compare Period is specifically designed to diagnose why performance changed between two time periods - it compares two AWR snapshots side-by-side and identifies the root cause of the degradation, making it the exact right tool when you observe a performance difference over time.

• A (Database Replay) is wrong because it replays a captured workload to test system changes (like upgrades or patches) - it doesn't diagnose an existing production regression.
• C (ASH report) shows active session activity during a single time window; it's great for spot analysis but doesn't natively compare two periods to explain a change.
• D (SQL Performance Analyzer) tests how specific SQL statements will perform after a change (e.g., optimizer upgrade) - it's predictive/testing-focused, not retrospective comparison.

Memory tip: Think "Compare Period = Compare Problem" - whenever the question mentions a difference or change in performance between two points in time, ADDM Compare Period is the answer. If it just says "diagnose current slowness," ASH or standard ADDM would apply instead.

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