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Advanced Lag Diagnosis: Spark

“My server is lagging” is the most common support request. To fix it effectively, we need precise data. Spark is a high-performance CPU and RAM profiler that identifies exactly which line of code is slowing down your “heartbeat” (TPS).
Reading TimeDifficultyLast Updated
8 minutesAdvancedJanuary 2026

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Running Your First Profiler

  1. Installation: Put spark.jar in your /plugins/ folder and restart. (Purpur users: Spark is built-in!).
  2. Start Monitoring: In-game or Console, run: 
    /spark profiler start
  3. The Data Window: Let the server run for 10 to 15 minutes while the lag is occurring. Empty servers do not provide useful data.
  4. Conclusion: Run /spark profiler stop.
  5. The Report: You will be given a link (e.g., spark.lucko.me/XXXXXX). Click it to view your results.

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Analyzing the Flame Graph

The Flame Graph displays a “stack trace” of what your CPU is doing.
  • Width = Time: The wider a bar is, the more of your server’s total processing time it consumed.
  • EntityTick: If this is wide, you have too many mobs/entities (farms).
  • Plugins: If a plugin name (e.g., EssentialsX) is wider than 10-15%, it is causing significant load.

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Memory Leaks

If your server crashes with “Out of Memory,” you can use /spark heapsummary to see which objects are filling your RAM. This is invaluable for identifying “Memory Leaks” in buggy or outdated plugins.

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Support Channels

If you need assistance or have any questions, please contact our support team:

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Last Updated: January 2026 | Minecraft: Diagnostics active.