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From: Joel Jacobson <[email protected]>
To: pgsql-hackers <[email protected]>
Subject: Re: Optimize LISTEN/NOTIFY
Date: Mon, 27 Oct 2025 07:18:37 +0100
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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On Mon, Oct 27, 2025, at 02:27, Chao Li wrote:
>> On Oct 27, 2025, at 07:24, Joel Jacobson <[email protected]> wrote:
>> 
>> Write-up of changes since v20:
>> 
>> Two new fields have been added to QueueBackendStatus:
>> + QueuePosition advisoryPos; /* safe skip-ahead position */
>> + bool advancingPos; /* backend is reading the queue */
...
> I did a quick review on v21 only focusing on the “direct advancement” logic.
>
> In v21, you added advisoryPos and advancingPos which is same as my 
> proposed solution. But you missed an important point from mine.
>
...
> From this perspective, we need to add a new field 
> adviancingTillPos to QueueBackendStatus. (This field was also missing 
> from my proposed patch).

I'm doubtful yet another field is worth the added complexity cost.

Before increasing the complexity further, I think we should first
try to simulate somewhat realistic workloads, to see if we actually
have a problem first.

/Joel

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