Skip site navigation (1) Skip section navigation (2)

Re: Collect frequency statistics for arrays

From: Nathan Boley <npboley(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alexander Korotkov <aekorotkov(at)gmail(dot)com>, Noah Misch <noah(at)leadboat(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Collect frequency statistics for arrays
Date: 2012-02-29 22:36:41
Message-ID: CAHetpQR89qzo45BeHKRNhD5321OcPs=FKPLyng3bzCuK8d_+ng@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Wed, Feb 29, 2012 at 12:39 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Alexander Korotkov <aekorotkov(at)gmail(dot)com> writes:
>> On Mon, Jan 23, 2012 at 7:58 PM, Noah Misch <noah(at)leadboat(dot)com> wrote:
>>> I've attached a new version that includes the UINT64_FMT fix, some edits of
>>> your newest comments, and a rerun of pgindent on the new files.  I see no
>>> other issues precluding commit, so I am marking the patch Ready for
>>> Committer.
>>> If I made any of the comments worse, please post another update.
>
>> Changes looks reasonable for me. Thanks!
>
> I am starting to look at this patch now.  I'm wondering exactly why the
> decision was made to continue storing btree-style statistics for arrays,
> in addition to the new stuff.

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?

Are you suggesting removing MCV's in lieu of MCE's as well?

-Nathan

In response to

Responses

pgsql-hackers by date

Next:From: Robert HaasDate: 2012-02-29 22:40:23
Subject: Re: Parameterized-path cost comparisons need some work
Previous:From: Robert HaasDate: 2012-02-29 21:55:18
Subject: Re: 16-bit page checksums for 9.2

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group