From: Andrew Gierth <andrew@tao11.riddles.org.uk>
To: Vladimir Ryabtsev <greatvovan@gmail.com>
Cc: tgl@sss.pgh.pa.us,  pgsql-performance@lists.postgresql.org
Subject: Re: Why Postgres doesn't use TID scan?
In-Reply-To: 
 <CAMqTPq=4Qp80Qt11DdHjjzM4ksp7O0wTmDQexSUbo2sEoTk+hQ@mail.gmail.com>
	(Vladimir Ryabtsev's message of "Mon, 17 Dec 2018 17:54:19 -0800")
Message-ID: <87bm5hwxy2.fsf@news-spur.riddles.org.uk>
References: 
 <CAMqTPq=hNg0GYFU0X+xmuKy8R2ARk1+A_uQpS+Mnf71MYpBKzg@mail.gmail.com>
	<31790.1545097237@sss.pgh.pa.us>
	<CAMqTPq=4Qp80Qt11DdHjjzM4ksp7O0wTmDQexSUbo2sEoTk+hQ@mail.gmail.com>
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Date: Wed, 19 Dec 2018 11:41:27 +0000
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>>>>> "Vladimir" == Vladimir Ryabtsev <greatvovan@gmail.com> writes:

 Vladimir> I can't believe it.
 Vladimir> I see some recommendations in Internet to do like this

well, 90% of what you read on the Internet is wrong.

 Vladimir> Did it really work in 2011? Are you saying they broke it?
 Vladimir> It's a shame...

The method in that SO link does work, it's just slow. The workaround is
to do it like this instead:

delete from mytable
 where ctid = any (array(select ctid from mytable
                          where ...
                          order by ...
                          limit 1000));

But of course that's still an ugly hack.

-- 
Andrew (irc:RhodiumToad)