issue about rowkey design

[ch huang]

hi,all
     i have data (data  is very huge) with user id ,session id ,and visit
time. my query pattern is ,"find all user id in certain time range,find one
user's all session id ,and find all session id in certain time range".
   my difficult is that i can not find a rowkey that good for all the
search pattern, i wonder if i need set three rowkey for these search
patterns,it's say i need triple my data storage ,any good idea?