Re: Proposal: Out-of-Order NOTIFY via GUC to Improve LISTEN/NOTIFY Throughput

On Fri, Jul 18, 2025, at 10:15, Joel Jacobson wrote:
> On Fri, Jul 18, 2025, at 02:49, Rishu Bagga wrote:
>> Hi all,
>>
>> There’s been some renewed attention on improving the performance of the
>> LISTEN/NOTIFY system, which historically hasn’t scaled well under high
>> notify frequency. Joel Jacobson recently shared some work on optimizing
>> the LISTEN path [1], and I wanted to follow up with a proposal focused on
>> the NOTIFY side.
>
> To clarify, my patch optimizes parallelizability of NOTIFY, without
> degrading parallelizability of LISTEN/UNLISTEN.

I realize my above clarification is not technically true,
what I meant to say is:

My patch improves NOTIFY TPS when many backends are listening on multiple
channels by eliminating unnecessary syscall wake‑ups, but it doesn't increase
the internal parallelism of the NOTIFY queue itself.

/Joel