Thanks Oleg for the link… It worked and my site is working smoothly.
However, the solution there was in two parts. 1st thing was Manual editing of one PHP code line and 2nd was running a PHP script to remove extra entries from wp_options table.
1st part worked for me but 2nd part, did not work. I could not login to WordPress after I installed MU-Plugin.
However, the writing and re-writing bug of cron job is fixed and no more database crash so I am happy, even if there are still 80K entries in wp_options table ??
