I also found devel.module measuring very unreliable in my opinion. The
slow queries are logged on random basis, query A executes in 50ms first
time and in 1ms second time...
This is most likely due to MySQL query caching.  Most queries can be cached so identical resulting queries will be very quick and it appears that is what you're seeing.
Rob Roy Barreca
Electronic Insight Corporation
12526 High Bluff Drive, Suite 300
San Diego, CA 92130
http://www.electronicinsight.com
rob@electronicinsight.com


Jakub Suchy wrote:
You can create a test site and populate it with as many nodes as you  
need using the generate-content.php script that ships with  
devel.module.  There are other scripts in there for creating users,  
taxonomy terms and even path aliases.  Devel module is also great for  
timing db queries.
    

Hi,
i started debugging one of my sites using Drupal 4.6, which is taking
about 1second to generate, which is probably slow (using few modules and
18n for 6 languages).

I found this query is not using index:
SELECT locale, name FROM locales_meta WHERE enabled = 1 ORDER BY isdefault DESC, name ASC;
This may be fixed using:
ALTER TABLE locales_meta ADD INDEX(enabled);
But i am not experienced in developing Drupal core yet, so could
somebody adopt this issue and add it to CVS please?

This query is executed more than 11 times every time:
SELECT s.lid, t.translation FROM locales_source s INNER JOIN locales_target t ON s.lid = t.lid WHERE s.source = '' AND t.locale = 'cs'
I don't understand where may appear empty locale string and can't
imagine how to debug this, can anybody help?

I also found devel.module measuring very unreliable in my opinion. The
slow queries are logged on random basis, query A executes in 50ms first
time and in 1ms second time...

Jakub Suchy