On Thu, Feb 13, 2025 at 7:44 AM PG Doc comments form
wrote:
> The following documentation comment has been logged on the website:
>
> Page:
> https://www.postgresql.org/docs/17/multivariate-statistics-examples.html
> Description:
>
> CREATE STATISTICS stts (dependencies) ON a, b FROM t;
> ANALYZE t;
> EXPLAIN (ANALYZE, TIMING OFF) SELECT * FROM t WHERE a = 1 AND b = 1;
> QUERY PLAN
>
> ---
> Seq Scan on t (cost=0.00..195.00 rows=100 width=8) (actual rows=100
> loops=1)
>Filter: ((a = 1) AND (b = 1))
>Rows Removed by Filter: 9900
>
>
> The result of the explain is a copy paste of previous example, so this
> example looks like the statistic doesn't improve things
>
Look more closely, and read the surrounding text. It talks about the
problem being the rows estimate.
David J.
