How to avoid mysql crash without blocking wp-cron.php?

Hi,

about since release 2.3.2 we experienced a high server load, due to some processes calling themselves, so the website was too slow or nearly crashing. We tried to solve this by adding “deny from {ip}” in the .htaccess file and the site started working good (except the future posting not working).
Now we just moved to another server and upgraded to wp 2.6 (passing through the other versions in time) and wanted to check if we had the same problem. We removed that “deny from ip” rule from the .htaccess to check, and we suddenly get “Error establishing database connection” and the table “wp_option” often corrupted, so I restored that rule and the site came back working fine.
I disabled all the plugins I could to try to discover what the real problem was, and I went on my new cpanel error logs panel and found this error:

[Sun Jul 27 02:49:31 2008] [error] [client {server ip}] client denied by server configuration: /home/swblog/public_html/wp-cron.php

So my deny rule is preventing wp-cron.php from running (that is why future posting has never worked so far).

I found many topics about server load related to wp-cron and found this one about spawn_cron() that seem to be very detailled
https://www.ads-software.com/support/topic/130492?replies=1 but I’m not sure if this can help me or not.

Do you think that this could solve my issue or do I have to change some configuration manually?

Thank you in advance.