Re: Columns correlation and adaptive query optimization

Konstantin Knizhnik <k.knizhnik@postgrespro.ru>

From: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>

To: legrand legrand <legrand_legrand@hotmail.com>, pgsql-hackers@postgresql.org

Date: 2019-10-15T07:46:38Z

Lists: pgsql-hackers

Attachments

join_selectivity.patch (text/x-patch) patch
auto_explain_create_statistics.patch (text/x-patch) patch


On 15.10.2019 1:20, legrand legrand wrote:
> Hello Konstantin,
>
> What you have proposed regarding join_selectivity and multicolumn statistics
> is a very good new !
>
> Regarding your auto_explain modification, maybe an "advisor" mode would also
> be helpfull (with auto_explain_add_statistics_threshold=-1 for exemple).
> This would allow to track which missing statistic should be tested (manually
> or in an other environment).
>
> In my point of view this advice should be an option of the EXPLAIN command,
> that should also permit
> auto_explain module to propose "learning" phase.
Thank you for good suggestion. Advisor mode is really good idea.
I have added "auto_explain.suggest_only" GUC.
When it is switched on, suggested CREATE STATISTICS statement is just 
printed in  log but not actually created.


-- 
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company