Reduce worker_manager memory allocation (#4435)

2026-04-09 18:26:19 +07:00
parent dd77b2d53a
commit 61530b61c6
22 changed files with 229 additions and 281 deletions
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+# 0079 - Reduce Twake Mail mobile memory usage
+
+Date: 2026-04-09
+
+## Status
+
+Accepted
+
+## Context
+
+Twake Mail is allocating a lot of memory on mobile.
+- ~375 MB on Android (Oneplus 8T)
+
+<img src="../images/android-before-4435.png">
+
+- ~297 MB on iOS (iPhone 11 Pro)
+
+<img src="../images/ios-before-4435.png">
+
+## Findings
+
+### `worker_manager` library's inefficient memory allocation (Android & iOS)
+- Version `5.0.3` counts the number of processors (x) on the device, create forever-live x - 1 isolates
+- Version `7.2.7` adds an ability to create isolate on-demand, and dispose when done. However, it still leaks 1 isolate when init.
+### `firebase_messaging` library's eager background Dart isolate (Android)
+- FirebaseMessaging.onBackgroundMessage() creates a forever-live isolate even when the app is in foreground.
+- Related: https://github.com/firebase/flutterfire/issues/17163
+### Unused `flutter_downloader` library's worker (iOS)
+- The only usage was deleted in https://github.com/linagora/tmail-flutter/commit/be8eaf625818b17e60ca65846053cb8c26a71a15#diff-451741ba5146e6ad711c77e4c2fe34958a36595e4926cd43c2ddb97586ef6d88, but the library and initialization process remained, causing 1 forever-live isolate.
+
+## Decision
+
+### `worker_manager`
+- Upgrade to `7.2.7`
+- Create an upstream fix for init's isolate leak
+### `firebase_messaging`
+- Wait for https://github.com/firebase/flutterfire/pull/18122, update when merged
+### `flutter_downloader`
+- Remove the library
+
+## Consequences
+
+- Android: ~118 MB
+
+<img src="../images/android-after-4435.png">
+
+- iOS: ~78 MB
+
+<img src="../images/ios-after-4435.png">
+
+- No changes for web
+
+| Before | After |
+| :--- | :--- |
+| <img src="../images/web-before-4435.png"> | <img src="../images/web-after-4435.png"> |