This is caused by #18844 in which we upgraded to newer rusty_v8 release. We had to disable "pointer compression" in our V8 build, because it was causing memory leaks (#18369).

The root issue is a V8 bug (https://bugs.chromium.org/p/v8/issues/detail?id=13640&q=garbage%20collection&can=2) which it appears now got some traction and might be fixed in the near(-ish) future. Once that happens we will turn back on pointer compression. For now the only remedy on your side is to increase the limit for old space.

@bartlomieju should we close this bug ( assuming there's another one tracking it ) ?

Let's keep it open for tracking purposes :)

I get the message "Fatal JavaScript out of memory: Ineffective mark-compacts near heap limit" in a previously working and untouched app. I assume that's the same bug?

That's correct, currently Deno requires more baseline heap size to function properly (because of the disabled pointer compression) so unfortunately you will have to increase the limits on your side as well.

I'm also experiencing this problem, and running deno test is the same error.

deno 1.33.1 (release, x86_64-pc-windows-msvc)
v8 11.4.183.1
typescript 5.0.3

Does 1.33.2 do anything to fix/workaround this? Is my app unusual for hitting this? I'd kind of expect a lot of noise and activity around a regression like this, but this issue doesn't have many comments.

Does 1.33.2 do anything to fix/workaround this? Is my app unusual for hitting this? I'd kind of expect a lot of noise and activity around a regression like this, but this issue doesn't have many comments.

No, there's no change in 1.33.2 to fix this. There's really nothing we can do until https://bugs.chromium.org/p/v8/issues/detail?id=13640&q=garbage%20collection&can=2 is fixed.

Is my app unusual for hitting this?

Maybe you have a very low heap size limit set? Most people use the default heap sizes so there's no problem of running out of heap size, besides overall slightly increased memory usage.

Is there any way to configure VSCode to use this mysterious flag for the language server? I couldn't find any obvious setting for it.

@denizdogan see #19088 (comment) -- It should be higher by default now though so you might not run into it as often.

When running our custom runtime built on Deno in a Docker container with 256MB memory, we run into this issue too.

Maybe you have a very low heap size limit set? Most people use the default heap sizes so there's no problem of running out of heap size, besides overall slightly increased memory usage.

What is the recommended configuration to avoid OOM? What is the recommended minimum memory size for running Deno-based apps in a container?

What is the recommended configuration to avoid OOM?

I can't really say, since it depends on the amount of internal JavaScript runtime code you have, you'll have to measure it experimentally.

What is the recommended minimum memory size for running Deno-based apps in a container?

The default setting should work fine in most cases, if you are storing huge objects in memory then you will need to increase the default heap size. It really depends on the given workload and there's no single one-size-fits-all in this case.

Reopening because of #20253. We discovered that after enabling pointer compression again we're still leaking memory. From https://bugs.chromium.org/p/v8/issues/detail?id=13640&q=garbage%20collection&can=2 it appears that the bug is still not fixed on V8 side.

Reopening because of #20253. We discovered that after enabling pointer compression again we're still leaking memory. From https://bugs.chromium.org/p/v8/issues/detail?id=13640&q=garbage%20collection&can=2 it appears that the bug is still not fixed on V8 side.

@bartlomieju it seems the bug was marked as fixed earlier this month.

I'm still having this issue on deno 1.43.3

It only made its way to v12.6-lkgr branch a few days ago. Follow #23838 for updates when it lands in Deno.

@eduardobbrito If you're on Linux, would you mind giving the PR artifact from 23838 a try with pointer compression enabled? Grab it from the artifacts dropdown at the top of https://github.com/denoland/deno/pull/23838/checks.