Re: Exception: This method must be called from inside the mailbox thread

Hi KristoffSC, I'd strongly suggest not blocking the task thread if it involves external services. RPC notification cannot be processed and checkpoints are delayed when the task thread is blocked. That's what AsyncIO is for. If your third party library just takes a few ms to finish computation wi

Re: Exception: This method must be called from inside the mailbox thread

Hi Arvid, Thank you for your answer. And what if a) would block task's thread? Let's say I'm ok with making entire task thread to wait on this third party lib. In that case I would be safe from having this exception even though I would not use AsyncIO? -- Sent from: http://apache-flink-user

Re: Exception: This method must be called from inside the mailbox thread

Hi KristoffSC, sorry for the confusing error message. In short, mailbox thread = task thread. your operator a) calls collector.collect from a different thread (in which the CompleteableFuture is completed). However, all APIs must always be used from the task thread. The only way to cross thread