> See "The unbearable slowness of IN()" at
> http://www.artfulsoftware.com/infotree/queries.php
Do you read your own links? Excerpt:
> In 5.0, EXISTS() is much faster than IN(), but slower than JOIN. In 5.5,
EXISTS() performs about as well as JOIN.
So judging by the subject line...
--
My
On 2012-07-06 5:07 PM, David Lerer wrote:
Cabbar, try to replace the IN subquery with an EXISTS. Something like:
SELECT * FROM A WHERE EXISTS (SELECT * FROM B WHERE A.id=B.A_ID and B.name
like 'X%');
See "The unbearable slowness of IN()" at
http://www.artfulsoftware.com/infotree/queries.
Cabbar, try to replace the IN subquery with an EXISTS. Something like:
SELECT * FROM A WHERE EXISTS (SELECT * FROM B WHERE A.id=B.A_ID and B.name
like 'X%');
Does it help?
David.
-Original Message-
From: Cabbar Duzayak [mailto:cab...@gmail.com]
Sent: Friday, July 06, 2012 11:46 AM
T
Benjamin:
I tried this, but it is slow as well, but it went down to something
like 20 seconds.
Reindl:
I was thinking about doing this on the app server side, but it
consumes more memory + requires multiple roundtrips, that is why I
wanted to do it on the mysql side. Also, like uses the index if
As far as I know, a B-tree index can be used by LIKE as long as the string
doesn't begin with a wildcard. " LIKE 'X%' " should be fine to use an index on
the name column. The index only includes results in the search base which start
with X.
That said, I probably wouldn't use a subquery, either
Am 06.07.2012 17:46, schrieb Cabbar Duzayak:
> Hi Everyone,
>
> I have been trying to understand why subqueries are taking tooo much
> time on my installation of MySQL 5.5.18 on Ubuntu 11.10 release.
>
> In a nutshell, I have 2 tables: A and B. And, I do something like this:
>
> SELECT * FROM
Hi Everyone,
I have been trying to understand why subqueries are taking tooo much
time on my installation of MySQL 5.5.18 on Ubuntu 11.10 release.
In a nutshell, I have 2 tables: A and B. And, I do something like this:
SELECT * FROM A WHERE A.id IN (SELECT A_ID FROM B WHERE B.name like 'X%');
T
Charming, Noel. Are you Devops? :-D
On Fri, Jul 6, 2012 at 3:09 AM, Noel Butler wrote:
> **
> For those interested 5.5.25a has been released overnight, long after
> oracle claimed it was there.
> frankly., I think they ought to have use 5.5.26.
>
> To those who replied to me directly, a few fact
Am 06.07.2012 04:09, schrieb Noel Butler:
> For those interested 5.5.25a has been released overnight, long after oracle
> claimed it was there.
>
> 2/ to the wanker who said people deserve what they get for untesting on DEV
> bed first ...
> this is true _IF_ it was a major release. (as I ho
