Re: Slow count(*) again... - Mailing list pgsql-performance

From Greg Smith
Subject Re: Slow count(*) again...
Date
Msg-id 4CB4602A.3040800@2ndquadrant.com
Whole thread Raw
In response to Re: Slow count(*) again...  (Jon Nelson <jnelson+pgsql@jamponi.net>)
Responses Re: Slow count(*) again...  (Jon Nelson <jnelson+pgsql@jamponi.net>)
List 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@2ndQuadrant.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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