Node.js Worker Threads: Unexpected Memory Leak with Large Data Processing
I'm optimizing some code but I keep running into I'm dealing with I've encountered a strange issue with I've searched everywhere and can't find a clear answer... I'm currently using Node.js v16.14.0 and attempting to process large datasets using worker threads. I've set up a simple worker that receives an array of objects, processes them, and sends back the results. However, I've noticed that the memory usage keeps increasing during processing and doesn't seem to release memory afterward, leading to a crash due to exceeding the available heap space. Here's a simplified version of my worker code: ```javascript // worker.js const { parentPort } = require('worker_threads'); parentPort.on('message', (data) => { // Simulate heavy processing const results = data.map(item => { // Assume some heavy computation here return { ...item, processed: true }; }); parentPort.postMessage(results); }); ``` And here's how I'm creating and managing the worker from my main thread: ```javascript // main.js const { Worker } = require('worker_threads'); function runService(data) { return new Promise((resolve, reject) => { const worker = new Worker('./worker.js'); worker.postMessage(data); worker.on('message', resolve); worker.on('error', reject); worker.on('exit', (code) => { if (code !== 0) { reject(new Error(`Worker stopped with exit code ${code}`)); } }); }); } (async () => { const largeDataSet = new Array(1000000).fill(0).map((_, i) => ({ id: i })); try { const results = await runService(largeDataSet); console.log('Processing complete:', results.length); } catch (err) { console.error('Error processing data:', err); } })(); ``` When I run this code, memory usage starts at around 50MB but quickly rises to over 1GB during processing. I tried using the `--max-old-space-size` flag to increase the heap size, but that doesn't seem to resolve the underlying memory leak. I've looked into using `--inspect` and `node --trace-gc` to monitor garbage collection, but it hasn't provided clear insights. Is there a specific approach or best practice I might be missing when dealing with worker threads and large datasets? Any help would be appreciated! I'm using Javascript 3.10 in this project. What am I doing wrong? Thanks for any help you can provide! The project is a microservice built with Javascript. Could this be a known issue? I'm on macOS using the latest version of Javascript. Is this even possible?