Re: Query take a long time and use no index - Mailing list pgsql-general

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
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