Re: "Big O" notation for postgres? - Mailing list pgsql-performance

From Richard Huxton
Subject Re: "Big O" notation for postgres?
Date
Msg-id 4834343A.8020607@archonet.com
Whole thread Raw
In response to Re: "Big O" notation for postgres?  ("Jonah H. Harris" <jonah.harris@gmail.com>)
Responses Re: "Big O" notation for postgres?  (Gregory Stark <stark@enterprisedb.com>)
List pgsql-performance
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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