Re: significant slowdown of HashAggregate between 9.6 and 10

On Thu, 2020-06-04 at 11:41 -0700, Andres Freund wrote:
> +/* minimum number of initial hash table buckets */
> +#define HASHAGG_MIN_BUCKETS 256
> 
> 
> I don't really see much explanation for that part in the commit,
> perhaps
> Jeff can chime in?

I did this in response to a review comment (point #5):


https://www.postgresql.org/message-id/20200219191636.gvdywx32kwbix6kd@development

Tomas suggested a min of 1024, and I thought I was being more
conservative choosing 256. Still too high, I guess?

I can lower it. What do you think is a reasonable minimum?

Regards,
    Jeff Davis