uksort takes a lot of time with large number of cron events

[geza.miklo]

wp-includes/cron.php: 49, 91

If crons are disabled in wp config:

/** Disable cron jobs */
define('DISABLE_WP_CRON', true);

Then the events just get collected and collected. We've imported more than 500k articles, and during that the cron array stored in the options table bacame huge. I mean really, really huge.

On every request it got loaded, parsed and sorted. ​https://secure.phabricator.com/book/phabflavor/article/php_pitfalls/#usort-uksort-and-uasort

Quick fix with filter:

add_filter('schedule_event', function() { return false;});
add_filter('pre_option_cron', function() { return array(); });

We are using wp-cli to run jobs. For the most needed we've written our own command (eg. activating future posts).

I see three options (two real solution exactly) to fix this error:

1. Disable collecting cron events where DISABLE_WP_CRON is set to true
2. Limit the size of the array
3. Try to avoid sorting (memory problems still will occur)

Please contact me if any information is needed.

[dd32]

DISABLE_WP_CRON only disables WordPress calling the cron, the constant is designed for when someone is using a external tool (such as curl via a system cronjob) to execute the actual cron script.

Due to the reliance upon cron, I don't think we want to make it easy to completely disable it though like you're doing..

[geza.miklo]

I understand and agree with your opinion. But I don't feel, that is makes sense to let the cron option grow without a limit.

[dd32]

FWIW though, you might also be being bitten by #33423, as the cron array isn't processed on every page load normally.

[geza.miklo]

Yeah it won't be, because I dont want it to be processed. You can't let it do that, if over a million pages are requested per day.

[peterwilsoncc]

Creating a custom storage system for site's with a large number of scheduled tasks is now possible with the changes introduced in WordPress 5.1, please refer to the ​dev note on the Make WordPress Core P2.

[peterwilsoncc]

Resetting this to closed: the status change appears to have got lost on the comment above.