From: Stephen Frost <sfrost@snowman.net>
To: Jon Nelson <jnelson+pgsql@jamponi.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgres INSERT performance and scalability
Date: Mon, 19 Sep 2011 21:32:41 -0400
Message-ID: <20110920013241.GR12765@tamriel.snowman.net> (raw)
In-Reply-To: <CAKuK5J0-fEHVm_c_H6T6XMk9PQE6zDohBHqZ39CHu5Hz0kGC4g@mail.gmail.com>
References: <CAMhtkAb1F1SOyz1mzeeWaQehoqtzk29oLVVG=NzKEoGS9bPDNg@mail.gmail.com>
<20110920005342.GO12765@tamriel.snowman.net>
<CAKuK5J0-fEHVm_c_H6T6XMk9PQE6zDohBHqZ39CHu5Hz0kGC4g@mail.gmail.com>
* Jon Nelson (jnelson+pgsql@jamponi.net) wrote:
> Isn't the WAL basically COW?
eh..? No.. The WAL is used to record what changes are made to the
various files in the database, it certainly isn't an kind of
"copy-on-write" system, where we wait until a change is made to data
before copying it..
If you INSERT .. SELECT, you're going to get the real data in the WAL,
and also in the heap of the new table..
Thanks,
Stephen
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To: pgsql-performance@postgresql.org
Cc: sfrost@snowman.net, jnelson+pgsql@jamponi.net
Subject: Re: Postgres INSERT performance and scalability
In-Reply-To: <20110920013241.GR12765@tamriel.snowman.net>
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