Deleting data from DBQLogTbl? - response (3) by teradatauser2

hi,
We have a process of moving data from dbc dbql tables to dbql history tables. But , off late we are facing spece crunch on these history databases as well.
There is a process of deleting data from these history pdcr tables as well. for e.g for sql table it's 3 months older purgig policy, for log and object table it is a year.
My question is :
1. where do i go and validate/get details this purging process ?
2. is this done automatically by TD routines or is it specific to a shop (using their own routines)
-thanks!