Significant Delay (10s) in Group Channel List Updates - Need Performance Optimization Guidance

Sendbird Chat API/SDK iOS
1

[Problem/Question] We’re experiencing significant performance issues with our group channel list updates. Specifically:

  1. When User B sends a message to User A who is viewing the message list, it takes ~10 seconds for B’s conversation to move to the top of A’s list
  2. Same delay occurs when A exits a chat window back to the message list

We’ve already tried:

  • Reducing channel list fetch limit from 2000 to 20
  • Following LocalCachingGroupChannel sample code patterns
  • Implementing without pagination to maintain real-time updates

Pagination creates data consistency issues:

  • If channel #23 gets updated while viewing page 1 (channels 1-20)
  • Channel #23 should move to position #1
  • When fetching page 2, channel #23 is missing
  • Channel #20 appears again at start of page 2

[SDK Version] Sendbird Chat SDK for iOS version 4.21.8

[Reproduction Steps]

  1. Set up two test users (e.g., User A: uid 267, User B: uid 99)
  2. User A opens message list view
  3. User B sends message to User A in a private channel (e.g., private_99_267)
  4. Observe ~10 second delay before channel appears at top of A’s list

Alternative scenario:

  1. User A is in chat with User B
  2. User A exits to message list
  3. Observe ~10 second delay before channel updates position

[Frequency]

  • Occurs consistently with every channel list update
  • Affects all users system-wide
  • Not specific to particular devices or regions
  • Recently seeing occasional faster updates (2-3 seconds)

[Current impact] This is critically impacting our implementation:

  • Preparing for launch with 30k waitlisted users
  • Social messaging app requiring real-time performance
  • 10-second delay severely impacts user experience
  • Need instant updates for competitive messaging experience
  • Cannot implement pagination due to data consistency requirements
  • Need solution that maintains both real-time updates and performance

Looking for guidance on:

  1. Optimizing channel list performance
  2. Achieving consistent fast updates
  3. Maintaining real-time functionality without pagination issues
  4. Recommended configurations or best practices
2

Adding to this thread as we are experiencing similar slowness with group channels and it seems to be particularly bad for certain users.

Someone reported over 1h for a channel to load for them which definitely does not sound right.

We still need to do more digging but have found that clearing the cookies and the cache seems to temporarily fix the problem