On Tue, Jul 15, 2025, at 09:20, Joel Jacobson wrote: > On Sun, Jul 13, 2025, at 01:18, Tom Lane wrote: >> "Joel Jacobson" <j...@compiler.org> writes: >>> The attached proof-of-concept patch proposes a straightforward >>> optimization for the single-listener case. It introduces a shared-memory >>> hash table mapping (dboid, channelname) to the ProcNumber of a single >>> listener. >> >> What does that do to the cost and parallelizability of LISTEN/UNLISTEN? > > Good point. The previous patch would effectively force all LISTEN/UNLISTEN > to be serialized, which would at least hurt parallelizability. > > New benchmark confirm this hypothesis. > > New patch attached that combines two complementary approaches, that together > seems to scale well for both common-channel and unique-channel scenarios:
Thanks to the FreeBSD animal failing, I see I made a shared memory blunder. New squashed patch attached. /Joel
0001-Subject-Optimize-LISTEN-NOTIFY-signaling-for-scalabi-v3.patch
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