# Diagnosing Minecraft Server Lag Using Spark Lag can ruin the player experience on your Minecraft server. Whether it’s a consistent delay or sudden spikes, diagnosing the cause is crucial for a smooth gaming environment. **Spark**, a performance profiling plugin, provides powerful tools to identify and resolve lag issues. This guide explains how to use Spark to diagnose lag spikes. # Understanding Lag Spikes **Lag spikes** occur when one or a few game ticks take significantly longer than average to execute. They might:
- Happen frequently (e.g., once every 20 ticks). - Occur rarely (e.g., once every minute). - Be tied to specific player actions or server events.
Lag spikes can be challenging to diagnose because typical profiling averages out the data, masking the spikes. However, Spark offers tools like `/spark tickmonitor` and `/spark profiler` to pinpoint these issues effectively. # Installing Spark If you’re running PaperMC for **1.21** or later, Spark is **already built in**, and you do not need to install it separately. For all other server types or older versions, you’ll need to install Spark manually. ### Installing Spark on Non-PaperMC Servers
1. **Download Spark** - Visit the [Spark Website](https://spark.lucko.me/download). - Download the latest version of Spark for your server type (e.g., `.jar` file for Paper, Spigot, or Bukkit). 2. **Place Spark in Your Server’s Plugins Folder** - Upload the downloaded `spark-x.x.x.jar` file to the `/plugins` folder of your server directory. 3. **Restart the Server** - Restart your Minecraft server to load the Spark plugin. 4. **Verify the Installation** - Once the server is running, use the `/spark` command in the server console or chat to verify the installation. - Run: ``` /spark ``` You should see Spark’s command list and version details.
# Use /spark tickmonitor to Detect Lag Spikes ### What Does `/spark tickmonitor` Do? This command tracks tick execution time and highlights spikes by comparing individual ticks against the server’s average tick duration. ### How to Use It
1. **Enable Monitoring** Run: ``` /spark tickmonitor ``` By default, Spark will report ticks that take 100% longer than the average. 2. **Set a Custom Threshold** You can use an absolute tick duration threshold. For example: ``` /spark tickmonitor --threshold-tick 50 ``` This will report any tick exceeding 50 milliseconds. 3. **Observe Gameplay** - Wait for a lag spike to occur. - Note the in-game effects during the spike and correlate them with the monitoring output in chat. 4. **Adjust Sensitivity if Needed** If no spikes are detected, lower the threshold: ``` /spark tickmonitor --threshold-tick 70 ```
### Example If a WorldEdit action creates a spike, you might see ticks reported with over 1000% increases in duration. # Profile Laggy Ticks Using /spark profiler ### What Does `/spark profiler` Do? The `/spark profiler` command captures detailed performance data. With the `--only-ticks-over` option, you can filter the profile to include only laggy ticks. ### How to Use It
1. **Choose a Threshold** Use the tick duration from Step 1 as a reference. For example, if laggy ticks exceed 150 milliseconds: ``` /spark profiler --only-ticks-over 150 ``` 2. **Run the Profiler** - The profiler will start recording, but only for ticks exceeding the threshold. - Let it run long enough to capture lag events. 3. **Stop the Profiler** Use: ``` /spark profiler stop ``` 4. **Inspect the Results** Open the profiling report and analyze the data. The laggy ticks will stand out, making it easier to identify the cause.
### Example In the profiler output, you might see a high percentage of time spent on a plugin, mod, or player action. This helps isolate the problem.
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# Common Causes of Lag Spikes
1. **Heavy Plugin Tasks** - Plugins like WorldEdit, if used on large areas, can cause spikes. - Identify such plugins in the profiler and adjust their usage or settings. 2. **Inefficient Mods or Data Packs** - Look for mods causing high execution times. - Update or replace inefficient mods. 3. **Resource Overload** - Large numbers of entities or block updates can cause spikes. - Use tools like `/kill @e[type=!player]` carefully to manage entities.
## Conclusion Using Spark’s tools, you can efficiently diagnose and address lag spikes on your Minecraft server. The combination of `/spark tickmonitor` for detection and `/spark profiler` for detailed analysis ensures you can pinpoint and resolve performance issues quickly. For further assistance or advanced optimization, consult the [Spark documentation](https://spark.lucko.me/).
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## Additional Help If you encounter any issues or need further assistance, open a support ticket via the [Billing Area](https://billing.ridgelineservers.com/tickets). Our support team is ready to assist you.