Firestore OOM crash when device still has 3GB free memory

[fanwgwg]

[READ] Step 1: Are you in the right place?

Issues filed here should be about bugs in the code in this repository. If you have a general
question, need help debugging, or fall into some other category use one of these other channels:

• For general technical questions, post a question on StackOverflow
  with the firebase tag.
• For general Firebase discussion, use the
  firebase-talk google group.
• For help troubleshooting your application that does not fall under one of the above categories,
  reach out to the personalized Firebase support channel.

[REQUIRED] Step 2: Describe your environment

• Android Studio version: Android Studio Panda 2 | 2025.3.2
• Firebase Component: Firestore
• Component version: com.google.firebase:firebase-bom:34.11.0

[REQUIRED] Step 3: Describe the problem

Steps to reproduce:

Unsure how to reproduce. We're only observing some crashes from this.

Stacktrace

  Fatal Exception: java.lang.OutOfMemoryError: Firestore (26.1.2) ran out of memory. Check your queries to make sure they are not loading an excessive amount of data.
       at com.google.firebase.firestore.util.AsyncQueue.lambda$panic$3(AsyncQueue.java:536)
       at android.os.Handler.handleCallback(Handler.java:997)
       at android.os.Handler.dispatchMessage(Handler.java:111)
       at android.os.Looper.loopOnce(Looper.java:237)
       at android.os.Looper.loop(Looper.java:325)
       at android.app.ActivityThread.main(ActivityThread.java:10404)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:635)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:970)

Caused by java.lang.OutOfMemoryError: Failed to allocate a 16 byte allocation with 3783120 free bytes and 3694KB until OOM, target footprint 536870912, growth limit 536870912; giving up on allocation because <1% of heap free after GC.
       at com.google.firebase.database.collection.ImmutableSortedSet.insert(ImmutableSortedSet.java:87)
       at com.google.firebase.firestore.local.ReferenceSet.addReference(ReferenceSet.java:57)
       at com.google.firebase.firestore.local.ReferenceSet.addReferences(ReferenceSet.java:64)
       at com.google.firebase.firestore.local.LocalStore.lambda$notifyLocalViewChanges$7(LocalStore.java:614)
       at com.google.firebase.firestore.local.SQLitePersistence.runTransaction(SQLitePersistence.java:218)
       at com.google.firebase.firestore.local.LocalStore.notifyLocalViewChanges(LocalStore.java:608)
       at com.google.firebase.firestore.core.SyncEngine.emitNewSnapsAndNotifyLocalStore(SyncEngine.java:711)
       at com.google.firebase.firestore.core.SyncEngine.handleRemoteEvent(SyncEngine.java:404)
       at com.google.firebase.firestore.core.MemoryComponentProvider$RemoteStoreCallback.handleRemoteEvent(MemoryComponentProvider.java:120)
       at com.google.firebase.firestore.remote.RemoteStore.raiseWatchSnapshot(RemoteStore.java:588)
       at com.google.firebase.firestore.remote.RemoteStore.handleWatchChange(RemoteStore.java:499)
       at com.google.firebase.firestore.remote.RemoteStore.access$100(RemoteStore.java:62)
       at com.google.firebase.firestore.remote.RemoteStore$1.onWatchChange(RemoteStore.java:190)
       at com.google.firebase.firestore.remote.WatchStream.onNext(WatchStream.java:114)
       at com.google.firebase.firestore.remote.WatchStream.onNext(WatchStream.java:38)
       at com.google.firebase.firestore.remote.AbstractStream$StreamObserver.lambda$onNext$1(AbstractStream.java:126)
       at com.google.firebase.firestore.remote.AbstractStream$CloseGuardedRunner.run(AbstractStream.java:67)
       at com.google.firebase.firestore.remote.AbstractStream$StreamObserver.onNext(AbstractStream.java:113)
       at com.google.firebase.firestore.remote.FirestoreChannel$1.onMessage(FirestoreChannel.java:162)
       at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1MessagesAvailable.runInternal(ClientCallImpl.java:667)
       at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1MessagesAvailable.runInContext(ClientCallImpl.java:654)
       at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
       at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
       at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:520)
       at java.util.concurrent.FutureTask.run(FutureTask.java:317)
       at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:348)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1154)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:652)
       at com.google.firebase.firestore.util.AsyncQueue$SynchronizedShutdownAwareExecutor$DelayedStartFactory.run(AsyncQueue.java:235)
       at java.lang.Thread.run(Thread.java:1564)

In Firebase crashlytics console, the device is shown with 2.99 GiB RAM free.

[dconeybe]

Thank you for the bug report.

Note that the amount of RAM free is not necessarily relevant because Android enforces a strict upper limit on how much RAM an individual process can consume, regardless of the amount of free RAM on the device. The exception message actually calls this out:

java.lang.OutOfMemoryError: Failed to allocate a 16 byte allocation with 3783120 free bytes and 3694KB until OOM, target footprint 536870912, growth limit 536870912; giving up on allocation because <1% of heap free after GC.

Specifically, target footprint 536870912, growth limit 536870912.

That being said, the crash unfortunately does not provide any details about what is consuming all of the RAM and, therefore, I can only speculate about what the root cause could be. If you're able to reproduce this issue then it would be possible to perform some memory profiling with Android Studio to pinpoint the culprit. But without that, there is not much I can do.

I do have a few suggestions though. Namely, Firestore maintains a local cache of documents downloaded from the server. By default this cache is stored in a sqlite database in the app's database directory. It is possible, though, to configure Firestore to use an in-memory database, which would obviously consume a considerable amount of RAM. By default the in-memory database has a soft size limit of 100 MB.

Could you check if your application is customizing the cache settings by setting FirebaseFirestoreSettings.cacheSettings (link).

Another possibility is that some of the documents are large, approaching the 1 MB size limit. So if an application runs a query that returns 500 documents each of 1 MB in size, then this will consume 500 MB of RAM.

Could you check if your application is returning large documents like this?

Finally, it could be that some other part of the application is consuming the majority of the RAM and Firestore is just the unfortunate part of the system that reaches the RAM growth limit.

[fanwgwg]

@dconeybe Thanks for getting back.

However, it's a bit mysterious to me that only happens after we upgrade from bom 34.10.0 to 34.11.0. We have >1M monthly active users and we receive OOM crashlytics reports from time to time, but this OOM crash at the line ImmutableSortedSet.insert is something that we see for the 1st time.

Is this something that worth attention?

[dconeybe]

@fanwgwg It is entirely possible that there is a memory leak or something like that introduced between bom 34.10.0 and 34.11.0. But the diff between those two releases for Firestore SDK is very small and does not suggest any net new memory leaks. The most helpful information at this point would be a "heap dump" (https://developer.android.com/studio/profile/capture-heap-dump) at a point when the memory "target footprint" is approaching the "growth limit". Is that something you'd be able to capture?

For posterity, this is the command that I ran to determine the diff, ignoring the "pipelines" changes, since I presume OP is not using pipelines:

git diff remotes/origin/releases/m177..remotes/origin/releases/m178 firebase-firestore/src/main/java/