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Em 05/10/2012 12:17, Mike Christensen
escreveu:
You could use a windowing function. Something like:
SELECT x, y, z, COUNT(*) OVER()
FROM Foo
LIMIT 50;
Good to know! I'll give a try!
On Fri, Oct 5, 2012 at 8:02 AM, P Gouv
<kadmos@xxxxxxxxx>
wrote:
You cant.
There is an article about count performance. Generally its
slow but latest version 9.2 i think supports index for count
under some condition.But 300 isnt that much that you should
worry.Another modern solution is to not count results just
add one more at limit to see if there is next page.
I've used two queries for >100 000 (with filters applied - table
has > 1 800 000 records), and is very acceptable (<200ms with
8Gb and Xeon dual core).
Edson.
On Fri, Oct 5, 2012 at 5:29 PM,
Moshe Jacobson <moshe@xxxxxxxxxxxx>
wrote:
We have a PHP web application that pulls results
from the database and paginates them.
We show e.g. "1-50 of 300" so the user knows
how many total results there are, and which ones
are currently being displayed.
To achieve this, we use a query with
LIMIT...OFFSET to get the displayed results, and
we do another identical query using count(*) to
get the total count.
Is there a more efficient way to do this that
does not require us to do two queries? I just feel
that it's a waste of resources the way we do it.
Thanks!
--
Moshe
Jacobson
Nead Werx, Inc. |
Senior Systems Engineer
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