On 21 July 2018 at 20:15, Didier Carlier wrote:
> explain select count(*) from calendar c1, calendar c2, measure m where
> c1.stddate='2015-01-01' and c2.stddate='2015-12-31' and m.fromdateid
> >=c1.calendarid and m.fromdateid < c2.calendarid;
>
I’m trying to find out why parallel queries are sometimes not used.
For example, I have 2 tables, calendar (1 row per day, ~3K rows) and measure
(~300M rows) which includes a FK to calendar.
I.e knowing two day numbers, I can find out how many measures there are between
these two dates with a
