Here i just need rowkey alone based on range based, Is there any problem in creating empty row alone throughout table.
Rowkey --> key1_date&time_key2
column --> empty
query --> select * from table where startkey=>key1_date&time and endkey=>key1_date&time
Goal is to extract key2
You may want to take a step back and look at your access patterns. If this is the only way you are planning on accessing this data, you can move key2 into the value section since you are not searching on it. If you will sometimes be searching on key1+key2 then it makes sense to keep it as a key. You shouldn't have a problem with the value being null but usually in a key-value system there is some sort of value you are looking for, so be sure to understand what it is you're searching for in this scenario and structure your data properly.