From: Richard Huxton <dev@archonet.com>
To: Jonah H. Harris <jonah.harris@gmail.com>
Cc: H. Hall <hhall1001@reedyriver.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: "Big O" notation for postgres?
Date: Wed, 21 May 2008 15:39:54 +0100
Message-ID: <4834343A.8020607@archonet.com> (raw)
In-Reply-To: <36e682920805210728p4fa6c12ft592b1045cbae9dfd@mail.gmail.com>
References: <48342D6D.1020506@reedyriver.com>
<36e682920805210728p4fa6c12ft592b1045cbae9dfd@mail.gmail.com>
Jonah H. Harris wrote:
> On Wed, May 21, 2008 at 10:10 AM, H. Hall <hhall1001@reedyriver.com> wrote:
>> Does anyone know if there is a source that provides "Big O" notation for
>> postgres's aggregate functions and operations? For example is count(*) =
>> O(1) or O(n)?
>
> I don't know of any document containing the complexity of each
> aggregate, but it's sometimes left as a comment in the souce code.
Recent max() and min() can be O(n) or O(1) depending on the where-clause
and presence of an index too, just to muddy the waters.
--
Richard Huxton
Archonet Ltd
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To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, jonah.harris@gmail.com, hhall1001@reedyriver.com
Subject: Re: "Big O" notation for postgres?
In-Reply-To: <4834343A.8020607@archonet.com>
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