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From: Tom Lane <[email protected]>
To: Robert Haas <[email protected]>
Cc: Anthonin Bonnefoy <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Add ALL_CANDIDATES option to EXPLAIN
Date: Fri, 26 Jul 2024 13:40:12 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <CA+TgmoYpwd7aidqF_pyeoddz6iUfFSQdy0ZBiH5eWxnvNn7-ig@mail.gmail.com>
References: <CAO6_Xqoke6qntHS8odYXT_P2Lrj7dNXgsCds+C8zLOXBbNefvg@mail.gmail.com>
	<CA+TgmoYpwd7aidqF_pyeoddz6iUfFSQdy0ZBiH5eWxnvNn7-ig@mail.gmail.com>

Robert Haas <[email protected]> writes:
> I've thought about trying to figure out some way of identifying and
> printing out plans that are "interestingly different" from the chosen
> plan, with the costs they would have had, but I haven't been able to
> come up with a good algorithm.

I wonder how far you'd get by just printing the surviving paths
(that is, something like Anthonin's patch, but without lobotomizing
add_path).  The survivors would have to dominate the cheapest-total
path along one of the other metrics add_path considers, which
seems like a rough approximation of "interestingly different".

			regards, tom lane

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