| From: | Greg Smith <greg(at)2ndquadrant(dot)com> |
|---|---|
| To: | Jon Nelson <jnelson+pgsql(at)jamponi(dot)net> |
| Cc: | mladen(dot)gogala(at)vmsinfo(dot)com, "david(at)lang(dot)hm" <david(at)lang(dot)hm>, Craig Ringer <craig(at)postnewspapers(dot)com(dot)au>, Vitalii Tymchyshyn <tivv00(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Slow count(*) again... |
| Date: | 2010-10-12 13:18:34 |
| Message-ID: | 4CB4602A.3040800@2ndquadrant.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers pgsql-performance |
Jon Nelson wrote:
> Is there a command to tell postgresql to drop/clear/reset it's buffer_cache?
>
No. Usually the sequence used to remove all cached data from RAM before
a benchmark is:
pg_ctl stop
sync
echo 3 > /proc/sys/vm/drop_caches
pg_ctl start
--
Greg Smith, 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services and Support www.2ndQuadrant.us
Author, "PostgreSQL 9.0 High Performance" Pre-ordering at:
https://www.packtpub.com/postgresql-9-0-high-performance/book
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