Re: Very newbie question

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  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?
>