How is the value of visitor_count_visits calculated in the table "piwik_log_visit"

Support & Bugs
1

I’m learning piwik, I have a problem of understanding how the value of visitor_count_visits is calculated in the table “piwik_log_visit”, can anyone help me?
and “visitor_days_since_last”, “visitor_days_since_first” : I think understand the value but not sure so much,
Thanks all,

2

any news on this topic?

3

number of visits

count of days since first visit

count of days since last visit