Achieving exactly-once delivery with Ably(ably.io)
ably.io
Achieving exactly-once delivery with Ably
https://www.ably.io/blog/achieving-exactly-once-message-processing-with-ably
https://www.ably.io/blog/achieving-exactly-once-message-processing-with-ably
Publisher: do at least once delivery, but only up to the next k minutes.
Each subscriber has a bitset of received IDs, filtering out redeliveries. Every 2*k minutes, bitset can be GC’d.