Horton

Re: Additional improvements to extended statistics

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-07-03T01:10:30Z
Lists: pgsql-hackers

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On Wed, Jul 01, 2020 at 01:19:40PM +0200, Daniel Gustafsson wrote:
>> On 24 Mar 2020, at 15:33, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:
>>
>> On Tue, Mar 24, 2020 at 01:20:07PM +0000, Dean Rasheed wrote:
>
>>> Sounds like a reasonable approach, but I think it would be better to
>>> preserve the current public API by having clauselist_selectivity()
>>> become a thin wrapper around  a new function that optionally applies
>>> extended stats.
>>>
>>
>> OK, makes sense. I'll take a stab at it.
>
>Have you had time to hack on this?  The proposed patch no longer applies, so
>I've marked the entry Waiting on Author.

Yep, here's a rebased patch. This does not include the changes we've
discussed with Dean in March, but I plan to address that soon.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Improve estimation of ANDs under ORs using extended statistics.

  2. Improve estimation of OR clauses using multiple extended statistics.

  3. Improve estimation of OR clauses using extended statistics.

  4. Prevent functional dependency estimates from exceeding column estimates.

  5. Fix wording of several extended stats comments

  6. Improve test coverage for multi-column MCV lists

  7. Improve test coverage for functional dependencies