Does using WP-cron make the site slower for the user?

If it’s a one-time maintenance issue then run the code manually at a time you chose.

If it’s a periodic maintenance task that might be heavy, use unix cron.

Otherwise, wp-cron can be used. You’re probably using it more than you know already. This plugin is great for monitoring wp-cron.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)