| From: | Enrique Sánchez <enriqueesanchz(at)gmail(dot)com> |
|---|---|
| To: | Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com> |
| Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org |
| Subject: | Re: Extended statistics improvement: multi-column MCV missing values |
| Date: | 2026-06-04 07:00:23 |
| Message-ID: | CAOCkzAntraDudo=zghSecb4d7f4fnveUiXDHUYVWAAhrhE2QSg@mail.gmail.com |
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| Lists: | pgsql-hackers |
Hi, thank you for reviewing it.
Tue, 02 Jun 2026 at 0:18, Zsolt Parragi (<zsolt(dot)parragi(at)percona(dot)com>) wrote:
> > The strongest
> > case is a top-level AND condition with equality clauses for all columns
>
> I see one issue related to that with the current patch, having the
> same amount of conditions as the table doesn't mean that we have
> conditions for all columns.
I've fixed this in the v2 patch attached above (also attached here for
completeness). It focuses on the basic full-dimensional top-level AND
equality miss
Now we construct a Bitmapset with the columns the clause covers and compare
it to `stat->keys` that contains the columns covered by the MCV statistic.
Best regards,
Enrique.
| Attachment | Content-Type | Size |
|---|---|---|
| v2-0001-Cap-selectivity-when-values-are-not-in-multi-colu.patch | text/x-patch | 10.4 KB |
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