Re: Columns correlation and adaptive query optimization

From: Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru>
To: legrand legrand <legrand_legrand(at)hotmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Columns correlation and adaptive query optimization
Date: 2019-10-15 07:46:38
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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:
The Russian Postgres Company

Attachment Content-Type Size
join_selectivity.patch text/x-patch 3.7 KB
auto_explain_create_statistics.patch text/x-patch 9.8 KB

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