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From: Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Cc: Jeff Davis <pgsql@j-davis.com>
Subject: Re: [HACKERS] PoC: full merge join on comparison clause
Date: Wed, 21 Nov 2018 16:02:47 +0300
Message-ID: <5351b58a-99ca-65fe-4bcd-7739bfedae33@postgrespro.ru> (raw)
In-Reply-To: <22877.1542592000@sss.pgh.pa.us>
References: <b31e1a2d-5ed2-cbca-649e-136f1a7c4c31@postgrespro.ru>
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	<636d3f40-be16-78cc-717f-b85e9f1b9362@postgrespro.ru>
	<20180123163126.GK2416@tamriel.snowman.net>
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	<CAFjFpRfAxa6CEKVA4E0mYXY+R+=2+o7H+Yk5h3PMfdRx5cTYvQ@mail.gmail.com>
	<9de15ac8-10b2-8569-4683-002db913! 1771@postgrespro.ru>
	<22877.1542592000@sss.pgh.pa.us>

On 11/19/18 04:46, Tom Lane wrote:
> In short, proceeding like the above when we can't find another plan
> type for a full join seems like it fixes a far wider variety of cases.
> The possibility that maybe we could do some of those cases a bit faster
> isn't sufficiently attractive to me to justify also putting in a
> mechanism like this patch proposes.  We only rarely see complaints at
> all about can't-do-a-full-join problems, and I do not think this patch
> would fix enough of those complaints to be worthwhile.


I agree, the automated UNION substitutions seems to be a better 
approach. I'll mark this patch as rejected then.


-- 
Alexander Kuzmenkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company





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