Today i was preparing report like whats Average Archive generation on my DB's so that i can arrange arch dests accordingly.
While doing this i was pulling data from v$log_history for date wise archive files count that got generated.
I know this much that v$log_history pulls data from control file.
But interesting thing i found that on each DB the number of entries in v$log_history are different. What i meant is some had data for last 150+ days while some had till 100 days only.
I mean its not a problem for me but Why is it like this?
My guess is Oracle internally manages control file and over writes/deletes data which is not needed as per the load activity on that DB to accomodate new data.
One thought also touched my mind is concept of "resetlogs opening of DB" but doesnt apply here as all the DB i checked are Prod DB's and they are in no way opened with resetlogs in last 1 yr or 2yr.
Anybody want to through light on this ??????