Re: Runtime variations during day - Mailing list pgsql-general

From Kevin Grittner
Subject Re: Runtime variations during day
Date
Msg-id 1360791352.37906.YahooMailNeo@web162901.mail.bf1.yahoo.com
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In response to Runtime variations during day  (Carlos Henrique Reimer <carlos.reimer@opendb.com.br>)
Responses Re: Runtime variations during day
Re: Runtime variations during day
List pgsql-general
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

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