Pierre-Frédéric Caillaud wrote:
Yes, you're right as usual.
As usual ? Do you think your father can be wrong on you ? :-)
Gaetano
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TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Yes, you're right as usual.
I had not thought about playing with ORDER BY on a field which has only
one value in the result set.
If you write it as
SELECT WHERE topic_id=2 ORDER BY topic_id DESC,id DESC.
then an index on (topic_id, id) will work fine. The mixed ASC/DESC
ordering is n
=?iso-8859-15?Q?Pierre-Fr=E9d=E9ric_Caillaud?= <[EMAIL PROTECTED]> writes:
> suppose I SELECT WHERE topic_id=2 ORDER BY topic_id ASC,id DESC.
> Postgres does a seq scan, but it could think a bit more and start at
> "first index node which has topic_id>2" (simple to find in a btree) th
OK, thanks a lot for your explanations. Knowing how the planner "thinks",
makes it pretty logical. Thank you.
Now another question...
I have a table of records representing forum posts with a primary key
(id), a topic_id, a timestamp, and other fields which I won't detail. I
want t
=?iso-8859-15?Q?Pierre-Fr=E9d=E9ric_Caillaud?= <[EMAIL PROTECTED]> writes:
> Now, if I LIMIT the query to 10 rows, the index should be used all the
> time, because it will always return few rows... well, it doesn't !
Not at all. From the planner's point of view, the LIMIT is going to
reduce the
On Mon, 6 Sep 2004, [iso-8859-15] Pierre-Frédéric Caillaud wrote:
> Why is it that way ? The planner should use the LIMIT values when
> planning the query, should it not ?
And it do use limit values, the estimated cost was lower when you had the
limit,
What you need to do is to tune pg
Update :
select * from apparts where departement=69 order by departement limit 10;
does use an index scan (because of the ORDER BY), even with OFFSET, and
it's a lot faster.
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TIP 9: the planner will ignore your desire to cho
Hello,
I have this table :
CREATE TABLE apparts
(
id SERIAL NOT NULL PRIMARY KEY,
priceFLOAT NOT NULL,
surfaceINTEGER NOT NULL,
price_sq FLOAT NOT NULL,
roomsINTEGER NULL,
vente
