slow-query

name	slow_query
description	Diagnose slow API/database query paths with Arthas trace. Use when users report high latency, timeout, or intermittent slow responses and need to locate the most time-consuming method path from an entry method to likely downstream bottlenecks.
nameI18nKey	skill.slow.query
descriptionI18nKey	skill.slow.query.desc

Slow Query Diagnosis Workflow

Goal

Determine whether the given entry method is actually slow, then drill down along the highest-cost call path to locate the likely bottleneck.

1. Confirm the Query Entry Point

Use the provided entry class and method directly. Do not request extra information unless entry point is missing.

2. Trace the Entry Method

Run:

trace <class> <method> -n 2 '#cost > 3000' --skipJDKMethod true

Notes:

• 3000 ms is the initial threshold.
• If timeout or no hit appears, treat it as no invocation above the current threshold.
• Lower threshold and retry.
• Never use threshold below 500 ms.

3. Retry Strategy

For entry method tracing, allow at most 4 attempts.

Use binary-search style narrowing:

• Start at 3000
• If no hit, lower threshold toward 500
• If hit, optionally raise threshold to isolate slower calls
• Keep adjustments fast and bounded

If no slow invocation is found after 4 attempts, stop the workflow and tell the user:

This method currently appears normal, and there is no sign of slow calls.

4. Continue Deeper Tracing

If entry method is slow, continue top-down drilling:

• Pick the highest-cost downstream method in current trace output
• Trace that method next with a reasonable threshold inferred from current cost
• Repeat for at most 3 deeper levels

Before each deeper trace, state:

• what method is currently hottest
• observed cost
• why it is chosen as next target

5. Communication Rules

During the investigation:

• Report each finding before issuing the next trace
• Keep focus on highest-cost path only
• Stop after 3 deeper levels even if deeper calls exist

6. Expected Outcome

Final output must include:

• whether entry method is slow
• slowest downstream method chain discovered
• likely bottleneck location (class/method)
• actionable next inspection point (SQL call site, RPC, cache miss path, lock/wait)