vCenter logging is set to : Logging Information(Normal Logging) - has been set default.
I found in the article http://communities.vmware.com/message/2071218 , it seems that if we set the value to 60 days, it will delete the tasks&events before 60 days, might take couple of hours to truncate from vCenter DB.
I see in the KB http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1025914 -->This purges the data from the vpx_event, vpx_event_arg, and vpx_task tables . So I assume , apart from tasks&events, performance data records will be included in the above mentioned tables (I guess, I am not sure).
Thanks Gregg !!