I have an annoiyng problem and i don't know how to solve it...

Since a week, in backend administration panel i got sometimes a warning like this:

MA DB function failed with error number 5
Out of memory (Needed 9228450 bytes) SQL=SELECT a.id, a.sectionid, a.title, a.created, u.name, a.created_by_alias, a.created_by FROM jos_content AS a LEFT JOIN jos_users AS u ON u.id = a.created_by WHERE a.state != -2 ORDER BY created DESC LIMIT 10
SQL =

SELECT id, title, module, position, content, showtitle, params
FROM jos_modules AS m
WHERE m.published = 1
AND m.position = 'header'
AND m.client_id = 1
ORDER BY m.ordering


It should be a PHP memory problem, but i took php memory from 128 mb to 172... and still have the problem... here you can look at php configuration

http://www.padovanews.it/phpinfo.php


Note: i have pagecache 2.0 and querycache installed...

Thank you!

nicola