by Luna Llena.
I am using Moodle 2.6 and I didn't have any problem with cron until today that shows "error writing to database". I do not what to do because I checked
max_execution_time
max_input_time
memory_limit
post_max_size
upload_max_filesize
and the values are the same I used in development and I do not have any problem in that Moodle.