Re: Sort time

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От Rod Taylor
Тема Re: Sort time
Дата
Msg-id 1037400019.62804.0.camel@jester
обсуждение исходный текст
Ответ на Re: Sort time  (Josh Berkus <josh@agliodbs.com>)
Список pgsql-performance
On Fri, 2002-11-15 at 16:18, Josh Berkus wrote:
> Rod,
>
> > > Hmmm ... how big *is* that varchar field?  8 characters gives us about 6mb
> for
> > > the column.  Of course, if it's a 128-char global unque id, that;s a bit
> > > larger.
> >
> > 20 characters long in the Unicode locale -- which is 40 bytes?
>
> Well, 40+, probably about 43.    Should be about 29mb, yes?
> Here's a question: is the total size of the column a good indicator of the
> sort_mem required?   Or does the rowsize affect it somehow?

I'd suspect the total row is sorted, especially in this case where he's
sorting more than one attribute.

--
Rod Taylor <rbt@rbt.ca>

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