Re: multivariate statistics v14 - Mailing list pgsql-hackers

From Tatsuo Ishii
Subject Re: multivariate statistics v14
Date
Msg-id 20160410.023757.532440443943028713.t-ishii@sraoss.co.jp
Whole thread Raw
In response to Re: multivariate statistics v14  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Responses Re: multivariate statistics v14  (Simon Riggs <simon@2ndQuadrant.com>)
Re: multivariate statistics v14  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Re: multivariate statistics (v19)  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
List pgsql-hackers
> But I still think it wouldn't move the patch any closer to committable
> state, because what it really needs is review whether the catalog
> definition makes sense, whether it should be more like pg_statistic,
> and so on. Only then it makes sense to describe the catalog structure
> in the SGML docs, I think. That's why I added some basic SGML docs for
> CREATE/DROP/ALTER STATISTICS, which I expect to be rather stable, and
> not the catalog and other low-level stuff (which is commented heavily
> in the code anyway).

Without "user-level docs" (now I understand that the term means all
SGML docs for you), it is very hard to find a visible
characteristics/behavior of the patch. CREATE/DROP/ALTER STATISTICS
just defines a user interface, and does not help how it affects to the
planning. The READMEs do not help either.

In this case reviewing your code is something like reviewing a program
which has no specification.

That's the reason why I said before below, but it was never seriously
considered.

>> - There are some explanation how to deal with multivariate statistics
>>   in "14.1 Using Explain" and "14.2 Statistics used by the Planner"
>>   section.

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



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