From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeff Davis <pgsql@j-davis.com>
cc: Robert Haas <robertmhaas@gmail.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: allowing extensions to control planner behavior
In-reply-to: <646c3d09475e49a5d1145c91af0ce3fdc3cdee96.camel@j-davis.com>
References: <CA+TgmoZY+baV-T-5ifDn6P=L=aV-VkVBrPmi0TQkcEq-5Finww@mail.gmail.com> <95e423ea042a8d2f85c76ee28feb7a5b10265f4d.camel@j-davis.com> <CA+TgmoY4yBRawLY-u0GM6aW7f0N4W8RU8WsZRb5+qhpWWfmZcQ@mail.gmail.com> <646c3d09475e49a5d1145c91af0ce3fdc3cdee96.camel@j-davis.com>
Comments: In-reply-to Jeff Davis <pgsql@j-davis.com>
	message dated "Wed, 28 Aug 2024 16:15:51 -0700"
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Date: Wed, 28 Aug 2024 19:25:59 -0400
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Jeff Davis <pgsql@j-davis.com> writes:
> Beyond awkwardness, one case where it matters is the interaction
> between an extension that provides hints and an extension that offers a
> CustomScan. How is the hints extension supposed to disable a path it
> doesn't know about?

This does not seem remarkably problematic to me, given Robert's
proposal of a bitmask of allowed plan types per RelOptInfo.
You just do something like

	rel->allowed_plan_types = DESIRED_PLAN_TYPE;

The names of the bits you aren't setting are irrelevant to you.

			regards, tom lane