Cold startup commonly takes about 18–28 seconds before the UI becomes interactive

Troubleshooting Mobile Apps
1

I can reproduce this issue consistently on Mattermost Mobile 2.43.1.

Environment:

- Device: Samsung Galaxy S24 (SM-S9210)

- Android: 16

- Android build: BP4A.251205.006 / S9210ZHU5DZDP

- Mattermost Mobile: 2.43.1, build 6000806

- Mattermost Server: 11.7.9 Team Edition

Symptoms:

- Cold startup commonly takes about 18–28 seconds before the UI becomes interactive.

- Reinstalling the app does not resolve the issue.

- The same behavior occurs with a newly created account containing only one team and two channels.

- It occurs both on direct 5G IPv4 and through NordVPN IPv4.

- The web client is fast on the same phone and network.

Mobile log findings:

- App initialization to routing the Home screen takes approximately 9–13 seconds.

- WebSocket connection itself completes in only 0.3–0.9 seconds.

- After WebSocket connection, Time to Interaction takes another 6–16 seconds.

- Example:

  • DatabaseManager initialization: 13:03:12.295

  • Route app to Home screen: 13:03:23.432

  • WebSocket connected: 13:03:24.210

  • Time to Interaction: 16480 ms

- Channel model processing takes only 20–459 ms.

- Server API responses are successful, with no network timeout or server error.

This appears to be client-side initialization/rendering latency on Android rather than a server, account-size, WebSocket, VPN, or IPv6 issue. The logs also show:

“PostListPerformanceTracker initialized (new architecture, android)”.

Could this be related to the React Native New Architecture, and is there any additional profiling information I can provide?

2

Thanks for the detailed investigation, @fuzzy_max_rice; the New Architecture log entry alone doesn’t establish the cause, but sharing full startup logs with sensitive details removed and, if possible, an Android system trace covering a cold launch until the UI becomes interactive would help narrow down the delay.