On 7/17/23 13:20, Tomas Vondra wrote:
> ...
>
> It's always going to be slow with the COUNT(DISTINCT), I'm afraid.
>
> Not sure how much you can modify the query / database, and how accurate
> results you need. If you're OK with estimates, you can try postgres-hll
> extension [2] which estimates count(distinct). For exact reaults, I
> wrote count_distinct extension [2] that uses hashtable. Might be worth a
> try, I guess.
>
Damn, I forgot to add the links:
[1] https://github.com/citusdata/postgresql-hll
[2] https://github.com/tvondra/count_distinct
regards
--
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company