Tips for finding memory leaks?
Any tips for finding memory leaks in a Nuxt application?
We've had a memory leak for quite some time that causes the server to run out of memory on regular intervals. I'm not very experienced in investigating and debugging memory leaks.
I'd appreciate any helpful tips or experiences from doing a memory leak investigation related to a running Nuxt application. ππ»
5 Replies
Hi @Jox. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:
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To find and debug memory leaks in a Nuxt application, here are some practical tips and tools based on the knowledge sources:
1. Inspect Plugins and Composables
Overusing plugins, especially those that perform expensive computations or take too long to initialize, can cause memory leaks. Review your plugins and consider refactoring some into composables or utility functions if possible. Inefficient plugins can block rendering and degrade user experience during hydration, leading to increased memory usage. Also, ensure you are not registering plugins, directives, or components multiple times, as this can cause memory leaks as well Nuxt performance: Common problems Plugins and Middleware. 2. Check for Unused Code and Dependencies
Unused code or dependencies can increase your bundle size and memory footprint. Regularly audit your
The Nuxt DevTools provide insights into your appβs performance, including a timeline for rendering and updating components, asset sizes, and a render tree to help identify bottlenecks and potential memory issues Nuxt DevTools. 4. Profile with External Tools
Use tools like Chrome DevTools, Node Inspector, and memory profilers to monitor memory usage and identify leaks. You can start Nuxt in debug mode with
Nuxt automatically purges cached data from
Avoid creating intervals, timeouts, or event listeners that are not properly cleaned up, as these can retain references and prevent garbage collection. 7. Monitor for Stale Async Data
There have been fixes in Nuxt to address issues where stale async data and fetcher functions could stick around, leading to memory leaks. Make sure you are using an up-to-date version of Nuxt to benefit from these fixes fix(nuxt): reinitialise stale async data. 8. Test in Production-like Environments
Sometimes, memory leaks only appear under production loads or specific OS environments (e.g., Ubuntu vs. Mac/Windows). Use stress tests and monitor memory usage over time in environments similar to your production setup Stack Overflow: PM2 + Node.js + Ubuntu. If you follow these steps and use the available tools, you should be able to identify and address most memory leaks in your Nuxt application. If you still encounter issues, try to create a minimal reproduction of the problem to isolate the cause and seek help from the community Reporting Bugs. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------
Overusing plugins, especially those that perform expensive computations or take too long to initialize, can cause memory leaks. Review your plugins and consider refactoring some into composables or utility functions if possible. Inefficient plugins can block rendering and degrade user experience during hydration, leading to increased memory usage. Also, ensure you are not registering plugins, directives, or components multiple times, as this can cause memory leaks as well Nuxt performance: Common problems Plugins and Middleware. 2. Check for Unused Code and Dependencies
Unused code or dependencies can increase your bundle size and memory footprint. Regularly audit your
package.json and codebase for unused utilities, composables, or functions Nuxt performance: Common problems.
3. Use Nuxt DevToolsThe Nuxt DevTools provide insights into your appβs performance, including a timeline for rendering and updating components, asset sizes, and a render tree to help identify bottlenecks and potential memory issues Nuxt DevTools. 4. Profile with External Tools
Use tools like Chrome DevTools, Node Inspector, and memory profilers to monitor memory usage and identify leaks. You can start Nuxt in debug mode with
nuxt dev --inspect and attach Chrome DevTools to analyze memory snapshots and heap usage Debugging.
5. Leverage Built-in Features to Prevent LeaksNuxt automatically purges cached data from
useAsyncData and nuxtApp.static.data on route navigation to help prevent memory leaks. This is controlled by the experimental.purgeCachedData option in your nuxt.config.ts (enabled by default). Disabling this may lead to stale data and increased memory usage purgeCachedData.
6. Be Careful with Long-Lived ReferencesAvoid creating intervals, timeouts, or event listeners that are not properly cleaned up, as these can retain references and prevent garbage collection. 7. Monitor for Stale Async Data
There have been fixes in Nuxt to address issues where stale async data and fetcher functions could stick around, leading to memory leaks. Make sure you are using an up-to-date version of Nuxt to benefit from these fixes fix(nuxt): reinitialise stale async data. 8. Test in Production-like Environments
Sometimes, memory leaks only appear under production loads or specific OS environments (e.g., Ubuntu vs. Mac/Windows). Use stress tests and monitor memory usage over time in environments similar to your production setup Stack Overflow: PM2 + Node.js + Ubuntu. If you follow these steps and use the available tools, you should be able to identify and address most memory leaks in your Nuxt application. If you still encounter issues, try to create a minimal reproduction of the problem to isolate the cause and seek help from the community Reporting Bugs. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------
<@525765413322227742> Kapa.ai is still learning and improving, please let me know how I did by reacting below.
If you're using vscode, you can install the "Flame Chart Visualizer for JavaScript Profiles" extension from Microsoft: https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-js-profile-flame
Then, create a
.vscode/launch.json with the following contents:
You should build your app like you would do in production: npm run build, which will create your build output -> .output
Then in VSCode go to the "Run and Debug" section on the left side of the editor and start the "Launch via Node" action. It will start your built app and you should see a section "Realtime Performance", where you can see in real time how much Memory, CPU percentage, etc. your application uses.
What i usually do is, i just throw out certain parts of the app, build it and watch the performance while using. If anything you threw out had a leak you should notice it in the before and after. Basically just repeat until you find it π
If you need some load you can use a load testing tool also, like https://github.com/hatoo/oha to simulate user traffic:
oha -n 1000 -c 5 http://localhost:3000 (run a thousand requests in total, 5 at a time, against localhost:3000)
Hope this helps, good luck! And let me know what the leak was if you don't mind πFlame Chart Visualizer for JavaScript Profiles - Visual Studio Mark...
Extension for Visual Studio Code - Flame graph visualizer for Heap and CPU profiles taken from the JavaScript debugger
GitHub
GitHub - hatoo/oha: Ohayou(γγ―γγ), HTTP load generator, insp...
Ohayou(γγ―γγ), HTTP load generator, inspired by rakyll/hey with tui animation. - hatoo/oha
Thanks a lot for the tips!
It took a while for me to get back on this issue but I'm on it now, and the Flame Chart Visualizer has been very helpful so far.
I've managed to narrow it down and am working on pinpointing and fixing the issue. I'll get back to you when I'm done π
The issue was the use of composables within a utils function.
Specifically a utility that creates a custom $fetch and is used quite frequently to get data from our backend.
Glad you found it!!