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From: Rishu Bagga <[email protected]>
To: Joel Jacobson <[email protected]>
Cc: pgsql-hackers <[email protected]>
Subject: Re: Optimize LISTEN/NOTIFY
Date: Tue, 15 Jul 2025 17:20:42 -0700
Message-ID: <CAK80=jhmE40KVqQ3ho37MArS7cAED1p9m7uikDxcnDmqdW7t8A@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
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Hi Joel,

Thanks for sharing the patch.
I have a few questions based on a cursory first look.

> If a single listener is found, we signal only that backend.
> Otherwise, we fall back to the existing broadcast behavior.

The idea of not wanting to wake up all backends makes sense to me,
but I don’t understand why we want this optimization only for the case
where there is a single backend listening on a channel.

Is there a pattern of usage in LISTEN/NOTIFY where users typically
have either just one or several backends listening on a channel?

If we are doing this optimization, why not maintain a list of backends
for each channel, and only wake up those channels?

Thanks,
Rishu

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