Wednesday, May 21, 2008

Re: [PERFORM] "Big O" notation for postgres?

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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