Re:Choose Postgres Queue Technology
by samus on Sunday September 24, 2023 @07:01PM
(#37638009)
I recently got introduced to this system at work, and also built a new job using it. It works fine, but since I had to implement work stealing to deal with abandoned jobs in a timely manner, I wouldn't dare to use it for actions that absolutely must not happen twice.
[ Parent
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Exactly-once is only meaningfully possible if you have a rollback for tasks of unknown completion state - for example if the task involves manipulating the same database as the one controlling the task execution. Otherwise, it becomes the (impossible to solve) two-generals problem between updating the task status and performing the task.
Full agree here.
There is actually another possibility: there must be a way to check whether the receiving system has received the message. But this only works if there are no "rogue" senders.