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Postgres LISTEN/NOTIFY does not scale

(www.recall.ai)
570 points davidgu | 2 comments | 07 Jul 25 14:05 UTC | HN request time: 0.41s | source
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hombre_fatal ◴[10 Jul 25 20:24 UTC] No.44525152[source]▶
Interesting. What if you just execute `NOTIFY` in its own connection outside of / after the transaction?
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parthdesai ◴[10 Jul 25 21:48 UTC] No.44526003[source]▶
You lose transactional guarantees if you notify outside of the transaction though
replies(2): >>44526146 #>>44534706 #
hombre_fatal ◴[10 Jul 25 22:02 UTC] No.44526146[source]▶
Yeah, but pub/sub systems already need to be robust to missed messages. And, sending the notify after the transaction succeeds usually accomplishes everything you really care about (no false positives).
replies(1): >>44526451 #
parthdesai ◴[10 Jul 25 22:35 UTC] No.44526451[source]▶
What happens when transaction succeeds but the execution of NOTIFY fails if it's outside of transaction, in it's own separate connection?
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1. Groxx ◴[11 Jul 25 01:18 UTC] No.44527506[source]▶
The same thing that happens if the notified process dies suddenly.

If you're not handling that, then whatever you're doing is unreliable either way.

replies(1): >>44528017 #
2. cheesekunator ◴[11 Jul 25 02:56 UTC] No.44528017[source]▶
98% of developers can't see it