Re: Extended multivariate statistics are ignored (potentially related to high null fraction, not sure)
| От | Danny Shemesh |
|---|---|
| Тема | Re: Extended multivariate statistics are ignored (potentially related to high null fraction, not sure) |
| Дата | |
| Msg-id | CAFZC=Qrj00c8m3BPw2934xwCf01Ou6AA7g04C3=7ggRrGOmZ7Q@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Extended multivariate statistics are ignored (potentially related to high null fraction, not sure) (Bruce Momjian <bruce@momjian.us>) |
| Список | pgsql-general |
Hey bruce, thanks for the prompt reply !
It reproduces in 12.11 and 13.7, we use a managed offering that is yet to include pg 14,
so sadly I can't try expressional extended statistics as of yet, nor can I attach gdb to the process
to debug the flow.
If any other directions come to mind, I'd really appreciate hearing them.
Thanks again !
On Wed, Jun 1, 2022 at 11:08 PM Bruce Momjian <bruce@momjian.us> wrote:
On Wed, Jun 1, 2022 at 07:28:58PM +0300, Danny Shemesh wrote:
> Hey everyone,
>
> I'm working on improving gathered statistics on several large tables (2TB /
> 500M records);
> I've created extended stats on correlated columns, ran analyze, compared the
> pre and post explains, and it seems as though the extended statistics are
> ignored -
> the estimation doesn't change much, and I can accurately derive the est. rows
> from multiplying the single-column freqs from pg_stats with the supplied
> values.
>
>
> Context:
> - pg 12.8
You should be on the most recent version of 12.X, and I do see some
extended statistics change in the later releases you are missing.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
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