Large group chat

• Differences between livecast room vs 10K group chat

  • Number of participants

  • Relationship between user and group

  • Duration of groups

• Challenges of livecast room

• Bottleneck of large group chat

  • Batch requests to get presence status

  • Batch requests to the same client gateway

  • Handle online users separately from offline users

  • Save offline messages asynchrnously

  • Different queue speed for different group

• References

Differences between livecast room vs 10K group chat

Number of participants

• For pure 10K group chat scenarios, 10K is already super big group

• For livecast room scenarios, 10K is pretty common, and it could be as high as million or 10 millions of participates.

  • 1M or 10M participates

Relationship between user and group

• For pure 10K group chat scenarios, the frequency of joining/leaving groups are pretty low.

• For livecast room scenarios, the frequency of joining/leaving livecast rooms are pretty high.

  • 10K/s-20K/s joining/leaving livecast room per second.

Duration of groups

• For pure 10K group chat scenarios, group memberships could last at least for months or years.

• For livecast room scenarios, group memberships could only last a few hours.

Challenges of livecast room

• Latency: Livecast room requires realtime interactions and low latency in APIs.

• End user experience: From end user perspective, each screen could fit 10-20 messages. If there are more than 20 messages per second pushed down to user device, the screen will stuck in a refreshing loop, resulting in bad user experience.

Bottleneck of large group chat

Batch requests to get presence status

Batch requests to the same client gateway

Handle online users separately from offline users

Save offline messages asynchrnously

Different queue speed for different group

References

• 大规模群消息推送如何保证实时性?

• IM技术分享：万人群聊消息投递方案的思考和实践