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help / color / mirror / Atom feedFrom: Chao Li <[email protected]>
To: Greg Sabino Mullane <[email protected]>
Cc: Jim Jones <[email protected]>
Cc: David G. Johnston <[email protected]>
Cc: Postgres hackers <[email protected]>
Subject: Re: ALTER TABLE: warn when actions do not recurse to partitions
Date: Thu, 12 Mar 2026 09:14:20 +0800
Message-ID: <[email protected]> (raw)
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> On Mar 12, 2026, at 00:39, Greg Sabino Mullane <[email protected]> wrote:
>
> On Wed, Mar 11, 2026 at 3:05 AM Chao Li <[email protected]> wrote:
> Are you concerning that rendering the full message text is the extra work? This is not a hot path, so I don’t think that would be a big deal. Actually, adding two more fields sounds more expensive
>
> Well, the recurring creation and freeing of the strings is the part that seems inefficient. But you don't even need to store the strings at all if you are tracking the action+rel. In such a case, the final strings can be created on the fly inside of EmitPartitionNoRecurseNotice, right? Then you just need a list to store the combos of action+relation.
>
Fully understood your point. My considerations are:
* This is not on a hot path, and that’s a very trivial performance impact.
* I would believe in most of use cases, ALTER TABLE won’t take duplicate sub-commands, thus duplicated messages should rarely happen.
* If we take your approach, actually, we don’t have to store action+relation in the list, only action is okay. But, if we defer building the notice message to EmitPartitionNoRecurseNotice, then we have to leave relation open till EmitPartitionNoRecurseNotice, which feels a worse burden. Looking at ATController(), rel is closed early. An alternative is to store the relation name in a temp variable, which also introduces extra code. As a trade-off, I think building the notice message in CollectPartitionNoRecurseNotice() is an easy implementation.
Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/
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Subject: Re: ALTER TABLE: warn when actions do not recurse to partitions
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