Nuxt.js: nuxt memory leak

[nnvgm]

Version

v2.12.2

Reproduction link

https://github.com/nnvgm/report-nuxt-memory-leak

Steps to reproduce

1. npx create-nuxt-app with typescript
2. docker-compose up -d
3. docker stats to display memory container is being used
4. use apache benchmark request to nuxt app with command ab -n 500 -c 5 -t 30 "http://localhost:3000/"

What is expected ?

memory is free

What is actually happening?

after request memory is not free.

_{This bug report is available on Nuxt community (#c10697)}

[Eygle]

Same problem, I tried a lots of benchmark to see where it come from and here as the results I got:

ℹ Memory usage: 155 MB (RSS: 235 MB)
ℹ Listening on: http://localhost:3000/
[12:00:35] Memory usage: 152 MB (RSS: 228 MB) - total heap: 194 MB - external: 4 MB
[12:00:45] Memory usage: 156 MB (RSS: 229 MB) - total heap: 195 MB - external: 4 MB
[12:00:55] Memory usage: 165 MB (RSS: 232 MB) - total heap: 198 MB - external: 4 MB
[12:01:05] Memory usage: 128 MB (RSS: 177 MB) - total heap: 145 MB - external: 4 MB
[12:01:15] Memory usage: 134 MB (RSS: 184 MB) - total heap: 152 MB - external: 4 MB
[12:01:25] Memory usage: 134 MB (RSS: 187 MB) - total heap: 154 MB - external: 4 MB
[12:01:35] Memory usage: 142 MB (RSS: 194 MB) - total heap: 165 MB - external: 4 MB
[12:01:45] Memory usage: 147 MB (RSS: 203 MB) - total heap: 169 MB - external: 4 MB
[12:01:55] Memory usage: 146 MB (RSS: 193 MB) - total heap: 161 MB - external: 4 MB
[12:02:05] Memory usage: 151 MB (RSS: 201 MB) - total heap: 172 MB - external: 4 MB
[12:02:15] Memory usage: 156 MB (RSS: 206 MB) - total heap: 179 MB - external: 4 MB
[12:02:25] Memory usage: 158 MB (RSS: 213 MB) - total heap: 182 MB - external: 4 MB
[12:02:35] Memory usage: 164 MB (RSS: 219 MB) - total heap: 186 MB - external: 4 MB
[12:02:45] Memory usage: 171 MB (RSS: 224 MB) - total heap: 199 MB - external: 4 MB
[12:02:55] Memory usage: 169 MB (RSS: 227 MB) - total heap: 209 MB - external: 4 MB
[12:03:05] Memory usage: 173 MB (RSS: 225 MB) - total heap: 191 MB - external: 4 MB
[12:03:15] Memory usage: 178 MB (RSS: 231 MB) - total heap: 199 MB - external: 4 MB
[12:03:25] Memory usage: 182 MB (RSS: 237 MB) - total heap: 201 MB - external: 4 MB
[12:03:35] Memory usage: 190 MB (RSS: 243 MB) - total heap: 214 MB - external: 4 MB
[12:03:45] Memory usage: 189 MB (RSS: 249 MB) - total heap: 218 MB - external: 4 MB
[12:03:55] Memory usage: 196 MB (RSS: 251 MB) - total heap: 218 MB - external: 4 MB
[12:04:05] Memory usage: 200 MB (RSS: 259 MB) - total heap: 228 MB - external: 4 MB
[12:04:15] Memory usage: 201 MB (RSS: 267 MB) - total heap: 243 MB - external: 4 MB
[12:04:25] Memory usage: 206 MB (RSS: 263 MB) - total heap: 233 MB - external: 4 MB
[12:04:35] Memory usage: 211 MB (RSS: 271 MB) - total heap: 237 MB - external: 4 MB
[12:04:45] Memory usage: 216 MB (RSS: 279 MB) - total heap: 248 MB - external: 4 MB
[12:04:55] Memory usage: 223 MB (RSS: 286 MB) - total heap: 252 MB - external: 4 MB
[12:05:05] Memory usage: 226 MB (RSS: 290 MB) - total heap: 269 MB - external: 4 MB
[12:05:15] Memory usage: 235 MB (RSS: 299 MB) - total heap: 272 MB - external: 4 MB
[12:05:25] Memory usage: 237 MB (RSS: 308 MB) - total heap: 276 MB - external: 4 MB
[12:05:35] Memory usage: 241 MB (RSS: 316 MB) - total heap: 282 MB - external: 4 MB
[12:05:45] Memory usage: 238 MB (RSS: 322 MB) - total heap: 298 MB - external: 4 MB
[12:05:55] Memory usage: 243 MB (RSS: 307 MB) - total heap: 275 MB - external: 4 MB
[12:06:05] Memory usage: 248 MB (RSS: 314 MB) - total heap: 287 MB - external: 4 MB
[12:06:15] Memory usage: 254 MB (RSS: 322 MB) - total heap: 290 MB - external: 4 MB
[12:06:25] Memory usage: 260 MB (RSS: 328 MB) - total heap: 294 MB - external: 4 MB
[12:06:35] Memory usage: 261 MB (RSS: 333 MB) - total heap: 311 MB - external: 4 MB
[12:06:45] Memory usage: 271 MB (RSS: 341 MB) - total heap: 314 MB - external: 4 MB
[12:06:55] Memory usage: 273 MB (RSS: 350 MB) - total heap: 318 MB - external: 4 MB
[12:07:05] Memory usage: 274 MB (RSS: 345 MB) - total heap: 325 MB - external: 4 MB
[12:07:15] Memory usage: 284 MB (RSS: 355 MB) - total heap: 327 MB - external: 4 MB
[12:07:25] Memory usage: 287 MB (RSS: 363 MB) - total heap: 331 MB - external: 4 MB
[12:07:35] Memory usage: 284 MB (RSS: 373 MB) - total heap: 349 MB - external: 4 MB
[12:07:45] Memory usage: 287 MB (RSS: 358 MB) - total heap: 324 MB - external: 4 MB
[12:07:55] Memory usage: 293 MB (RSS: 365 MB) - total heap: 332 MB - external: 4 MB
[12:08:05] Memory usage: 298 MB (RSS: 372 MB) - total heap: 346 MB - external: 4 MB
[12:08:15] Memory usage: 303 MB (RSS: 380 MB) - total heap: 350 MB - external: 4 MB
[12:08:25] Memory usage: 308 MB (RSS: 389 MB) - total heap: 355 MB - external: 4 MB
[12:08:35] Memory usage: 309 MB (RSS: 394 MB) - total heap: 376 MB - external: 4 MB
[12:08:45] Memory usage: 317 MB (RSS: 397 MB) - total heap: 379 MB - external: 4 MB
[12:08:55] Memory usage: 327 MB (RSS: 407 MB) - total heap: 382 MB - external: 4 MB
[12:09:05] Memory usage: 326 MB (RSS: 415 MB) - total heap: 386 MB - external: 4 MB
[12:09:15] Memory usage: 328 MB (RSS: 428 MB) - total heap: 393 MB - external: 4 MB  

How I did the benchmark

I chose to send one request per second and to print memory usage each 10 seconds using this code at the beginning of nuxt.config.js file:

setInterval(() => {
  const { heapUsed: used, rss, heapTotal: tot, external: ext } = process.memoryUsage()
  const f = (value: number) => (!value ? '-' : `${Math.round(value / 1048576)} MB`)

  console.log(
    `[${new Date().toTimeString().substr(0, 8)}] Memory usage: ${f(used)} (RSS: ${f(rss)}) - total heap: ${f(
      tot
    )} - external: ${f(ext)}`
  )
}, 10000)

Even with the lightest application I see a memory leak (javascript, npm and no other deps)

I tried with Nuxt version 2.0.0 and also with version 2.12.2

I launched this bash command to run a request per minute:

while :; do; curl http://localhost:3000/ > /dev/null; sleep 1; done

More info

With bigger applications the memory goes full very quickly! I have an app which take roughly 600MB at startup and crash in 3-5 minutes when receiving a request per second (and with targeting only an 404 error layout, so no component loaded).

[galvez]

    "start": "nuxt start",
    "start": "NODE_ENV=production nuxt start",

See if the leak still happens. Seems you're profiling Nuxt in development mode.

[Eygle]

I am profiling it in development mode (sorry I should have make that clear).
Our app running with nuxt start does not have the memory leak.

[manniL]

Memory leaks in dev mode are unavoidable as far as I know. ~Closing here~ as no memory leak is present in the prod build.

The OP's repo hasn't been checked yet.

[Eygle]

May I know why memory leaks are unavoidable ?

We are not talking about a few KB of leaks but 5MB to 20MB per request depending of your app weight.

Our stack, including a health check that requested our app every 5 seconds, ended up crashing every 2 - 3 hours in dev mode which is really annoying and not a good development experience at all!

The only solution we found was to disable the health check (not optimal) and running the app under a pm2 to ensure it's reboot in case of crashes.

[stale[bot]]

Thanks for your contribution to Nuxt.js!
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