Re: Distinct performance dropped by multiple times in v16

On Mon, Jun 10, 2024 at 3:32 AM Vitaliy Litovskiy <
vitaliy(dot)litovskiy(at)gmail(dot)com> wrote:

> 1. query runs for 4-5 seconds on v16 and less than a second on v15
>

Yeah, that's a big regression. Seeing the actual EXPLAIN ANALYZE output
for both systems would be very helpful to us. Also nice to see the plan if
you do a
SET enable_incremental_sort=0;
before running the query

I wonder if materializing things might help, something like

with
x as (select id, unnest(string_to_array(emp,';')) as token, refdate from
terr),
y as (select id, unnest(string_to_array(emp,';')) as token from employee)
select distinct x.id, y.id, refdate from x join y using (token);

(renamed to avoid all those mixed-case quoting)

Cheers,
Greg