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Postgres LISTEN/NOTIFY does not scale

(www.recall.ai)
570 points davidgu | 1 comments | 07 Jul 25 14:05 UTC | HN request time: 0.364s | 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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nick_ ◴[10 Jul 25 20:47 UTC] No.44525408[source]▶
My thought as well. You could add notify commands to a temp table during the transaction, then run NOTIFY on each row in that temp table after the transaction commits successfully?
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1. zbentley ◴[10 Jul 25 22:32 UTC] No.44526428[source]▶
This is roughly the “transactional outbox” pattern—and an elegant use of it, since the only service invoked during the “publish” RPC is also the database, reducing distributed reliability concerns.

…of course, you need dedup/support for duplicate messages on the notify stream if you do this, but that’s table stakes in a lot of messaging scenarios anyway.