CODEWITHSUNDEEP
erlang
egbokul
egbokul

Reputation: 3974

Erlang message processing transaction

When is the "transaction" of a process trying to fetch a message from its message queue considered to be committed or rolled back? In other words, at what point of execution is the message removed permanently from the message queue?

Upvotes: 1

Views: 120

Answers (1)

Michael
Michael

Reputation: 3729

When it is read by a receive call.

If a message is in a message queue and read by the process calling receive then it's just memory manipulation, and no other process can contend for the data so there's no transactional nature to it as such; there's no need for locking or rolling back, etc, but because it's just memory manipulation it doesn't matter.

The language you use makes me worry you think there are more guarantees than there are. It's important to remember that at the fundamental message send and receive level (without any extra layer on top that OTP might provide or you might write yourself) you are sending messages without any guarantee they will be delivered, or that the process you are sending to even exists.

Upvotes: 3

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