Re: Runtime variations during day

Carlos Henrique Reimer <carlos.reimer@opendb.com.br> wrote:

> I`m trying to figure out why a query runs in 755ms in the morning
> and 20054ms (26x) in the evening.

I would make autovacuum settings much more aggressive, or schedule
periodic VACUUM and/or ANALYZE runs during the day.

> database size is 40GB and memory 64GB

If you haven't already done so, I would use settings something like
this in postgresql.conf:

effective_cache_size = 32GB
seq_page_cost = 0.1
random_page_cost = 0.1
cpu_tuple_cost = 0.03

--
Kevin Grittner
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company