Magento 2 cron_schedule table increasing and CPU 100%

Question

I updated to 2.2.1 from 2.1.10 and that looked good. But my CPU is increasing a lot and it went to over 100% in a few days.

The problem is the cron jobs because also the table cron_schedule was very full with 249.000 rows.

Any idea what causes the problem in the cronjobs?

Answer 1

Maybe our questions are related

edit/update: clearing your cron_schedule table should temporarily fix your problem:

TRUNCATE cron_schedule;

to permanently fix your problem you have to find out why your cron_schedule table is growing. In my case, it is the missing mail server!

if you don't care about indexing and sending emails, you could also disable your crontab entries.

Answer 2

In my case, turns out the slow query was an update join on the cron_schedule table.

Found a related site on this. Solution - You can clear it with a daily script to delete completed records. https://www.optiweb.com/magento-2-cron-issues/

There should be a configuration for each cron groupfor the history cleanup and lifetimes.

<history_cleanup_every>10</history_cleanup_every>
<history_success_lifetime>60</history_success_lifetime> 
<history_failure_lifetime>600</history_failure_lifetime>

However, this only cleans up cron entries with the status »success« or »missed« and does not clean old entries with the status »pending«.

Simple Script: to delete cron_schedule records created a day ago copied from optiweb.com link above.

<?php
use Magento\Framework\App\Bootstrap;

$rootDirectory = *Magento root directory*;
require $rootDirectory . '/app/bootstrap.php';

$params = $_SERVER;
$bootstrap = Bootstrap::create(BP, $params);
$objectManager = $bootstrap->getObjectManager();
$resource = $objectManager->get('Magento\Framework\App\ResourceConnection');
$connection = $resource->getConnection();
$tableName = $resource->getTableName('cron_schedule');


$sql = "DELETE FROM " . $tableName . " WHERE created_at < DATE_SUB(NOW(), INTERVAL 1 DAY)";

try{
    $result = $connection->query($sql);
}catch(Exception $ex){
    print_r($ex);
}

Seems to do the trick, although I'm not sure about the interval may bump it to 7 days.