Re: Slow index scan on B-Tree index over timestamp field
| От | Igor Neyman |
|---|---|
| Тема | Re: Slow index scan on B-Tree index over timestamp field |
| Дата | |
| Msg-id | A76B25F2823E954C9E45E32FA49D70EC4283C108@mail.corp.perceptron.com обсуждение исходный текст |
| Ответ на | Re: Slow index scan on B-Tree index over timestamp field (Caio Casimiro <casimiro.listas@gmail.com>) |
| Список | pgsql-performance |
From: Caio Casimiro [mailto:casimiro.listas@gmail.com]
Sent: Monday, November 04, 2013 4:33 PM
To: Igor Neyman
Cc: Jeff Janes; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Slow index scan on B-Tree index over timestamp field
These are the parameters I have set in postgresql.conf:
work_mem = 128MB
shared_buffers = 1GB
maintenance_work_mem = 1536MB
fsync = off
synchronous_commit = off
effective_cache_size = 2GB
The hardware is a modest one:
CPU: Intel(R) Atom(TM) CPU 230 @ 1.60GHz
RAM: 2GB
HD: 1TV 7200 RPM (WDC WD10EZEX-00RKKA0)
This machine runs a slackware 14.0 dedicated to the Postgresql.
Thank you,
Caio
With just 2GB RAM, this:
shared_buffers = 1GB
and this:
effective_cache_size = 2GB
is too high.
You should lower those:
shared_buffers = 256MB
effective_cache_size = 1GB
and see how your execution plan changes.
Oh, and this:
maintenance_work_mem = 1536MB
is also too high.
Turning off fsync and synchronous_commit is not very good idea.
Regards,
Igor Neyman
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