Distributed Data - CRDT expiry

[SJern]

Over app needs to store some short-lived data that needs to be durable for a short period of time (5 min). It would be very useful if we could set some TTL on these data so they do not blow up the RAM and save the memory space for the persistent actors.
Please refer to akka/akka#27683

[He-Pin]

I have not looked into the akka issue yet, but that may need included timestamp in the entities and an expiration time after write or access？

[SJern]

Thanks for the response, He-Pin.
yeah looks like they added a usedTimestamp in ReplicatorMessages.proto
https://github.com/akka/akka/pull/31721/files
What's the typical amount of effort to port a feature from Akka? Is there any establish flow?

[pjfanning]

Thanks for the response, He-Pin. yeah looks like they added a usedTimestamp in ReplicatorMessages.proto https://github.com/akka/akka/pull/31721/files What's the typical amount of effort to port a feature from Akka? Is there any establish flow?

We cannot port Akka code to Pekko. The Akka code has an incompatible license. The Akka license change is the reason we had to create Apache Pekko in the first place.

Any code for this will have to be written from scratch without any reference to the Akka change.

[mkurz]

We cannot port Akka code to Pekko. The Akka code has an incompatible license. The Akka license change is the reason we had to create Apache Pekko in the first place.

The pull requests you are refering to all made it into Akka 2.8.0: https://github.com/akka/akka/releases/tag/v2.8.0
3 years after the release the licence automatically changes to Apache 2, so in theory next year Mar 16, 2026, you could just integrate that changes from Akka.

[pjfanning]

We cannot port Akka code to Pekko. The Akka code has an incompatible license. The Akka license change is the reason we had to create Apache Pekko in the first place.

The pull requests you are refering to all made it into Akka 2.8.0: https://github.com/akka/akka/releases/tag/v2.8.0 3 years after the release the licence automatically changes to Apache 2, so in theory next year Mar 16, 2026, you could just integrate that changes from Akka.

Possibly. I would need to get the ASF Legal advisors to decide on this.

It would be less problematic if a greenfield solution was provided but we can revisit this next year if no such solution exists by then.