From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew@dunslane.net>
cc: David Rowley <dgrowleyml@gmail.com>, Peter Geoghegan <pg@bowt.ie>,
        Robert Haas <robertmhaas@gmail.com>,
        pgsql-hackers@lists.postgresql.org,
        Andrew <pgsqlhackers@andrewrepp.com>
Subject: Re: pg_dump versus hash partitioning
In-reply-to: <a7ef6212-f9fe-6826-9640-5dac54327140@dunslane.net>
References: <1376149.1675268279@sss.pgh.pa.us> <CA+TgmoaZ8kDKiQMtDq82Qqqgc5JAfF_UEvc2qa46QwVVLvtMDw@mail.gmail.com> <1412538.1675283692@sss.pgh.pa.us> <CA+TgmoYoSoX8bN_yzabmRDQBNxEaWmjBKPnkZPMUDpPTBy=d4A@mail.gmail.com> <CAH2-WzkjKCmVD9JDKHx09YC+c5kSL_1rHH0kRMyvDHRFoxgw6Q@mail.gmail.com> <CA+TgmoYJ+3XpW_iYapXN3gwq2MECi7GH8BxuwKFCQPOzLaa3OQ@mail.gmail.com> <CAH2-Wz=cMRoYHeoac7kscdDNBSYzHKgMvSHX5CFEoE66rimk8A@mail.gmail.com> <1425446.1675291093@sss.pgh.pa.us> <CAApHDvqJM5HxhZSnxESENAHLxTZ=eXKKHxeHfvVe1E8v28woDA@mail.gmail.com> <1440373.1675299790@sss.pgh.pa.us> <a7ef6212-f9fe-6826-9640-5dac54327140@dunslane.net>
Comments: In-reply-to Andrew Dunstan <andrew@dunslane.net>
	message dated "Thu, 02 Feb 2023 07:56:22 -0500"
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Date: Thu, 02 Feb 2023 09:52:34 -0500
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Andrew Dunstan <andrew@dunslane.net> writes:
> On 2023-02-01 We 20:03, Tom Lane wrote:
>> Anyway, after re-reading the old thread I wonder if my first instinct
>> (force --load-via-partition-root for enum hash cases only) was the
>> best compromise after all.  I'm not sure how painful it is to get
>> pg_dump to detect such cases, but it's probably possible.

> Given the other problems you enumerated upthread, I'd be more inclined
> to go with your other suggestion of
> "--load-via-partition-root=on/off/auto" (with the default presumably
> "auto").

Hmm ... is there any actual value in "off" in this case?  We can be
just about certain that dump/reload of a hashed enum key will fail.

If we made "auto" also use --load-via-partition-root for range keys
having collation properties, there'd be more of an argument for
letting users override it.

			regards, tom lane