From: D'Arcy J.M. Cain <darcy@druid.net>
To: Dave Dutcher <dave@tridecap.com>
Cc: lists@peufeu.com
Cc: pgsql-performance@postgresql.org
Subject: Re: INSERT OU UPDATE WITHOUT SELECT?
Date: Tue, 30 May 2006 19:05:08 -0400
Message-ID: <20060530190508.aa47bafe.darcy@druid.net> (raw)
In-Reply-To: <039201c6843b$f11eeaf0$8300a8c0@tridecap.com>
References: <op.tadyc1jwcigqcu@apollo13>
<039201c6843b$f11eeaf0$8300a8c0@tridecap.com>
On Tue, 30 May 2006 17:54:00 -0500
"Dave Dutcher" <dave@tridecap.com> wrote:
> What I do when I'm feeling lazy is execute a delete statement and then
> an insert. I only do it when I'm inserting/updating a very small number
> of rows, so I've never worried if its optimal for performance. Besides
> I've heard that an update in postgres is similar in performance to a
> delete/insert.
Well, they are basically the same operation in PostgreSQL. An update
adds a row to the end and marks the old one dead. A delete/insert
marks the row dead and adds one at the end. There may be some
optimization if the engine does both in one operation.
--
D'Arcy J.M. Cain <darcy@druid.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.
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To: pgsql-performance@postgresql.org
Cc: darcy@druid.net, dave@tridecap.com, lists@peufeu.com
Subject: Re: INSERT OU UPDATE WITHOUT SELECT?
In-Reply-To: <20060530190508.aa47bafe.darcy@druid.net>
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