Re: Collect frequency statistics for arrays
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Nathan Boley <npboley@gmail.com>
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Noah Misch <noah@leadboat.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2012-02-29T23:10:44Z
Lists: pgsql-hackers
Nathan Boley <npboley@gmail.com> writes: > On Wed, Feb 29, 2012 at 2:43 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> Nathan Boley <npboley@gmail.com> writes: >>> If I understand you're suggestion, queries of the form >>> SELECT * FROM rel >>> WHERE ARRAY[ 1,2,3,4 ] <= x >>> AND x <=ARRAY[ 1, 2, 3, 1000]; >>> would no longer use an index. Is that correct? >> No, just that we'd no longer have statistics relevant to that, and would >> have to fall back on default selectivity assumptions. > Which, currently, would mean queries of that form would typically use > a table scan, right? No, it doesn't. > What about MCV's? Will those be removed as well? Sure. Those seem even less useful. regards, tom lane