RealmException: posix_fallocate() failed

[peachypixels]

What happened?

Hello!

I've been using Realm (.Net) 11.5.0 in Unity for months now with no issues (Windows Editor & Android Builds)

After upgrading to 11.6.1 it's still working in the Editor, but the attached exception is thrown when retrieving a Realm instance on Android.

The lock file is created, but the Realm (and other associated files) are not. This occurs whether opening an existing Realm or creating a new.

Unity Version: 2022.3.13f1
Android Version: 10 (ARM64 \ IL2CPP)

Repro steps

See attached code.

Version

11.6.1

What Atlas Services are you using?

Local Database only

What type of application is this?

Unity

Client OS and version

Android 10 (ARM64 \ IL2CPP)

Code snippets

RealmConfiguration config = new RealmConfiguration([file]);
config.EncryptionKey = [key];
config.Schema = new Type[] { typeof([type]) };
config.FallbackPipePath = [path];

Realm realm = Realm.GetInstance(config);

Stacktrace of the exception/crash you're getting

RealmException: posix_fallocate() failed: Operation not supported on transport endpoint: Operation not supported on transport endpoint (95)
Realms.NativeException.ThrowIfNecessary ()
Realms.SharedRealmHandle.Open (Realms.Native.Configuration configuration)
Realms.RealmConfiguration.CreateHandle (Realms.Native.Configuration& configuration)
Realms.RealmConfigurationBase.CreateRealm ()

Relevant log output

No response

[fealebenpae]

Hey @peachypixels. Thanks for reporting this. Can you reproduce it on the Android Emulator, or is it a specific device that exhibits the error?

[peachypixels]

Hi @fealebenpae. Thanks for the prompt reply. Sorry I'm not using the Android Emulator, just the Unity Editor and on-device builds (built with Unity Build Automation). I will try the build on a second Android device and report back.

[peachypixels]

Hi @fealebenpae. Just tried on a completely different Android (8) device and the exact same issue. As far as I can tell, there are no changes with any of my Realm calls between the last build (using 11.5.0 that worked) and this build (using 11.6.1)

I'll try and add some extra logging to see if it helps, but I'm beginning to think it's a wider issue with 11.6.1 and Android.

[fealebenpae]

Can you tell me what device models you’re running on and where on the filesystem the realm file is stored? I want to figure out if it has anything to do with the filesystem, because our automated tests didn’t turn up anything on Emulator or the devices we have access to.

[peachypixels]

The devices were a OnePlus7 (Android 10) & Lenovo Tab4 (Android 8). The Unity project install location is currently Prefer External and both devices have no extra storage, so it must be using internal.

Both devices are writing data to... /storage/emulated/0/Android/data/[bundle]/files/[etc]

Note... the OnePlus7 was originally failing to create the Realm, until the FallbackPipePath was defined (as outlined here)...

https://www.mongodb.com/community/forums/t/writing-to-android-persistent-storage-with-unity-throws-read-only-file-system-error/224093

[fealebenpae]

Thanks for the extra details. I have an idea how we might fix this, but I would like to be able to reproduce first. I’ll update here once I have learned more.

[peachypixels]

Ok, thanks for the update. I'm going to revert to 11.5.0 for now and will report back if this resolves the issue.

[peachypixels]

FYI. Reverting to 11.5.0 has resolved the issue on both devices. So it's almost definitely an 11.6.x issue.

[peachypixels]

Thanks everyone!