Re: multivariate statistics v14

From: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Subject: Re: [HACKERS] multivariate statistics v14
Date: Fri, 8 Apr 2016 20:55:24 +0200
Message-ID: <5d1d62a6-6228-188c-e079-c1be59942168(at)2ndquadrant(dot)com>

> On 04/08/2016 05:55 PM, Robert Haas wrote:
>> On Tue, Mar 29, 2016 at 11:18 AM, David Steele <david(at)pgmasters(dot)net>
>> wrote:
>>> On 3/28/16 4:42 AM, Tomas Vondra wrote:
>>>> Yes, those are valid omissions. I plan to address them, and I'd also
>>>> considering adding a section to 65.1 (How the Planner Uses
>>>> Statistics),
>>>> explaining more thoroughly how the planner uses multivariate stats.
>>>
>>> It looks you need post a new patch so I have marked this "waiting on
>>> author".
>>
>> Since no new version of this patch has been posted in the last 10
>> days, it seems clear that there will not be time for this to
>> reasonably become ready for committer and then get committed in the
>> few hours remaining before the deadline. That is a bummer, since I
>> was hoping we would have this feature in this release, but hopefully
>> we will get it into 9.7. I am marking it Returned with Feedback.
>>
>
> Well, me to. But my feeling is the patch received entirely
> insufficient amount of thorough code review, considering how important
> part of the code it touches. I agree docs are an important part of a
> patch, but polishing user-level docs would hardly move the patch
> closer to being committable (especially when there's ~50kB of
> READMEs).

My feedback regarding docs were:
> - There's no docs for pg_mv_statistic (should be added to "49. System
> Catalogs")
>
> - The word "multivariate statistics" or something like that should
> appear in the index.
>
> - There are some explanation how to deal with multivariate statistics
> in "14.1 Using Explain" and "14.2 Statistics used by the Planner"
> section.

The second and the third point maybe are something like "polishing
user-level" docs, but I don't think the first one is for "user-level".
Also I think without the first one the patch will be never
committable. If someone add a new system catalog, the doc should be
added to "System Catalogs" section, that's our standard, at least in
my understanding.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp