There is no reason to use index. The query has neither WHERE nor ORDER BY clause.
Toomas > On 23. Oct 2023, at 18:13, Олег Самойлов <spl...@ya.ru> wrote: > > Back pardon, but I have a very newbie question. I have a partitioned table, > partitioned by primary bigint key, size of partition 10000000. I need to get > the number of partition which need to archive, which has all rows are olden > then 3 month. Here is query: > > SELECT id/10000000 as partition > FROM delivery > GROUP BY partition > HAVING max(created_at) < CURRENT_DATE - '3 month'::interval; > > The 'id/10000000 as partition' is a number of the partition, it later will be > used inside the partition name. > The query runs long by sequence scan. Has anyone any ideas how to rewrite > query so it will use any index? >
