Re: "VACUUM FULL ANALYZE" vs. Autovacuum Contention

From: Greg Smith <greg(at)2ndQuadrant(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: "VACUUM FULL ANALYZE" vs. Autovacuum Contention
Date: 2011-07-08 17:12:46
Message-ID: 4E173A8E.80900@2ndQuadrant.com
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On 07/08/2011 12:46 PM, D C wrote:
> That said, it sounds like if we switched to daily "trucates" of each
> table (they can be purged entirely each day) rather than "delete
> froms", then there truly would not be any reason to use "vacuum
> full". Does that sound plausible?

That's exactly right. If you can re-arrange this data to be truncated
instead of deleted, this entire problem should go away. There is also a
nice optimization you should know about; if you do this:

BEGIN;
TRUNCATE t;
COPY t FROM ...
COMMIT;

In single-node systems (no standby slave), this can work much faster
than a normal load. It's able to skip the pg_xlog WAL writes in this
situation.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
Comprehensive and Customized PostgreSQL Training Classes:
http://www.2ndquadrant.us/postgresql-training/

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