There appears to be a memory leak issue

[zhuscat]

This is the minimal reproducible repo I created: https://github.com/zhuscat/test-nitro-sqlite

1. git clone https://github.com/zhuscat/test-nitro-sqlite
2. cd test-nitro-sqlite
3. npx expo prebuild --platform ios
4. xed ios
5. Edit Scheme -> Build Configuration -> Release
6. Build and then run the current scheme

I'm running it on my iPhone using Xcode with the Build Configuration set to Release.

I keep clicking "Create user database and insert 10000 records" and notice that memory usage keeps increasing. Even after I stop clicking, the memory doesn't decrease at all.

[zhuscat]

Also, I tried writing the same logic in a Swift app, and I didn't see any big memory spikes. The memory usage didn't keep going up, either.

[mrousavy]

Hey!

This doesn't 100% mean that there is a memory leak.
All this means is that neither Young GC or Old GC considers the allocated objects to be relevant for collection.

Whether that's because they have very complex cyclic references and are still being used somewhere, or because the objects don't properly implement getMemorySize() from Nitro, or because the RAM is so big (running on a real device or on a Mac?) that it can just grow without hitting GC.

if you reload the app (e.g. by pressing r in metro console), does the memory go down then? If no, then that's definitely a memory leak.

[mrousavy]

I think HybridNativeQueryResult would be a good candidate for implementing getMemorySize() from Nitro (see Hybrid Objects | memorySize), cc @chrispader

[chrispader]

if you reload the app (e.g. by pressing r in metro console), does the memory go down then? If no, then that's definitely a memory leak.

@zhuscat do you have by any chance tried what @mrousavy's mentioned here?

I'll hopefully be able to further investigate this issue soon!

[evelant]

FWIW I'm seeing a massive memory leak in react-native-nitro-image -- haven't had time to make a repro yet (will open relevant issue there when I do) but I suppose it could be related if there's a leak somewhere in core nitro-modules.

[mrousavy]

I'm seeing a massive memory leak in react-native-nitro-image

Did you also try what I said 2 months ago here? Try reloading the app by pressing r in metro - does the memory go down or stay up?

[evelant]

Didn't test in development mode. In release mode simply switching to a view with some nitro images and back on android grows heap by 500-1000mb then app OOM kills with no trace by the 3rd-4th time. Will try to put together a repro and proper issue on nitro-image since it's not necessarily related to this issue.

[chrispader]

This is what i see when i reload the example app after running a couple of NitroSQLite operations. The memory usage goes back to where it was when the app was first started (before running any SQLite operations). So i don't think we have a memory leak in NitroSQLite.

Screen.Recording.2026-02-11.at.13.32.06.mov

[chrispader]

@evelant @mrousavy i'll close this issue out for now. Lmk if you think this is still valid.

I'm adding getExternalMemorySize() support in #261