MySQL cron_schedule update problem

Question

For some reason this runs every day at a random time (MySQL cron_schedule update). Its causing our system to slow down or even become unresponsive for a few minutes.

Does anyone know what is this doing? Today it ran for 1960 second

Slow query trace 1:05 PM 7,200,000ms MAX TIME ACTION Query UPDATE cron_schedule SET status = ? WHERE (schedule_id = ?) AND (status = ?) Stack trace …nt::execute called at /home/removeduserd/public_html/lib/Zend/Db/Statement/ Pdo.php (0) …ute called at /home/removeduserd/public_html/lib/Varien/Db/Statement/Pdo/ Mysql.php (110) …Mysql::_execute called at /home/removeduserd/public_html/lib/Zend/Db/ Statement.php (320) …:execute called at /home/removeduserd/public_html/lib/Zend/Db/Adapter/ Abstract.php (479) …uery called at /home/removeduserd/public_html/lib/Zend/Db/Adapter/Pdo/ Abstract.php (238) …query called at /home/removeduserd/public_html/lib/Varien/Db/Adapter/Pdo/ Mysql.php (419) …l::query called at /home/removeduserd/public_html/lib/Zend/Db/Adapter/ Abstract.php (632) …/home/removeduserd/public_html/app/code/core/Mage/Cron/Model/Resource/ Schedule.php (63) …alled at /home/removeduserd/public_html/app/code/core/Mage/Cron/Model/ Schedule.php (217) …/home/removeduserd/public_html/app/code/community/Aoe/Scheduler/Model/ Observer.php (64) …tch called at /home/removeduserd/public_html/app/code/core/Mage/Core/Model/ App.php (1338) …hod called at /home/removeduserd/public_html/app/code/core/Mage/Core/Model/ App.php (1317) …ore_Model_App::dispatchEvent called at /home/removeduserd/public_html/app/ Mage.php (447) in Mage::dispatchEvent called at /home/removeduserd/public_html/cron.php (46)

Answer 1

This seems to be the core Magento cron process.

It doesn't run at random time but depends on how you setup cron to be run on server. It might be that some cron process is taking longer time to process blocking subsequent call.

So my guess at this stage is that there's a cron job that is causing a bottleneck. You can investigate by installing a profiler, or just disable every cron, activate one by one and monitor.