woocommerce internal server error on schedule job execution

I have create a custom plugin for products update in woocommerce from an other system. I have also add my plugin in cron schedule of wordpress.

But when i have a lot of products to update, i get error 500, internal server error.

In the start the procedure interrupted with error about time limit, so i raise the time limit ( set_time_limit(xxxxx);

Furthermore i have raise memory limit in wp-config.php file What else i can do ?

Regards S

via Chebli Mohamed