Answer by Frank Heikens for Poor performance bucketing historical data with DISTINCT

I think your current query is wrong. Please check this one:

SELECT  CAST(day AS date) AS day  , COALESCE(SUM(bad),0) AS bad  , COALESCE(SUM(awful),0) AS awful  , COALESCE(SUM(catastrophic),0) AS catastrophicFROM problem_reports  RIGHT JOIN GENERATE_SERIES(        DATE_TRUNC('day', '2025-03-01'::date),        DATE_TRUNC('day', '2025-03-07'::date),'1 day'::interval) gs(day) USING(day)GROUP BY 1ORDER BY 1;

When you have an index on the column day it should be fast.