Today on Elixir Wizards, Manuel Rubio, author of Erlang/OTP: A Concurrent World and Dan Plyukhin, creator of the UIGC Actor Garbage Collector for Akka, join host Dan Ivovich to compare notes on garbage collection in actor models.
The discussion digs into the similarities and differences of actor-based garbage collection in Erlang and Akka and introduces Dan's research on how to perform garbage collection in a distributed actor system.
Topics discussed:
Akka is akin to Erlang actors for the JVM using Scala, with similar principles like supervision trees, messages, and clusteringErlang uses generational garbage collection and periodically copies live data to the old heap for long-lived elementsActor GC aims to determine when an actor's memory can be reclaimed automatically rather than manually killing actorsDistributed actor GC is more challenging than object GC due to the distributed nature and relationships between actors across nodesChallenges include reasoning about failures like dropped messages and crashed nodesGC balance requires optimization of resource release and CPU load managementImmutability helps Erlang GC, but copying data for messages impacts performanceResearch into distributed actor GC is still ongoing, with opportunities for improvementFault tolerance in Erlang relies on user implementation rather than low-level guaranteesAsynchronous messages in Erlang/Elixir mean references may become invalid which is similar to the distributed GC approaches in Dan's researchIdempotent messaging is recommended to handle possible duplicates from failuresHelp your local researcher! Researchers encourage communication from practitioners on challenges and use casesLinks mentioned:
Erlang/OTP Volume 1: A Concurrent World by Manuel Rubio https://altenwald.com/en/book/en-erlang-i
Scala https://www.scala-lang.org/
Akka Framework https://github.com/akka
JVM (Java Virtual Machine) https://www.java.com/en/download/
The BEAM VM https://www.erlang.org/blog/a-brief-beam-primer/
Hadoop Framework https://hadoop.apache.org/
Pony Programming Language https://www.ponylang.io/
SLSA Programming Language https://wcl.cs.rpi.edu/salsa/#:~:text=SALSA%20
Paxos Algorithm https://en.wikipedia.org/wiki/Paxos_(computer_science)
Raft library for maintaining a replicated state machine https://github.com/etcd-io/raft
Dan's Website https://dplyukhin.github.io/
Dan Plyukhin on Twitter: https://twitter.com/dplyukhin
Dan Plyukhin’s YouTube channel: https://m.youtube.com/@dplyukhin
UIGC on GitHub https://github.com/dplyukhin/UIGC
Manuel's Website https://altenwald.com/
Manuel Rubio on Twitter: https://twitter.com/MRonErlang
Special Guests: Dan Plyukhin and Manuel Rubio.