Re: Postgres 15 SELECT query doesn't use index under RLS
| От | Tomek |
|---|---|
| Тема | Re: Postgres 15 SELECT query doesn't use index under RLS |
| Дата | |
| Msg-id | CACUaW3RUoQu6i7LHUOPe3Rg28AzTc052GH-Pn1fK1+nZaukQ7A@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Postgres 15 SELECT query doesn't use index under RLS (Alexander Okulovich <aokulovich@stiltsoft.com>) |
| Ответы |
Re: Postgres 15 SELECT query doesn't use index under RLS
|
| Список | pgsql-performance |
Hi Alexander!
Apart from the problem you are writing about I'd like to ask you to explain how you interpret counted frac_MCV - for me it has no sense at all to summarize most_common_freqs.
Please rethink it and explain what was the idea of such SUM ? I understand that it can be some measure for ratio of NULL values but only in some cases when n_distinct is small.
regards
Statistics: n_distinct, MCV, histogram
Useful to check statistics leading to bad join plan. SELECT (SELECT sum(x) FROM unnest(most_common_freqs) x) frac_MCV, tablename, attname, inherited, null_frac, n_distinct, array_length(most_common_vals,1) n_mcv, array_length(histogram_bounds,1) n_hist, correlation FROM pg_stats WHERE attname='...' AND tablename='...' ORDER BY 1 DESC;
Returns 0 rows.
Kind regards,
Alexander
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