Mridul, What do you mean about "Counter's are not synchronized in 'real-time' " ? As I know, JT will aggregate Counters from TT, so I think the aggregated Counter in JT should be correct.
On Tue, Jan 26, 2010 at 3:08 PM, Mridul Muralidharan <[email protected]>wrote: > Jeff Zhang wrote: > >> *See my comments below* >> >> >> On Mon, Jan 25, 2010 at 3:22 PM, Something Something < >> [email protected]> wrote: >> >> If I set # of reduce tasks to 1 using setNumReduceTasks(1), would the >>> class >>> be instantiated only on one machine.. always? I mean if I have a cluster >>> of >>> say 1 master, 10 workers & 3 zookeepers, is the Reducer class guaranteed >>> to >>> be instantiated only on 1 machine? >>> >>> *--Yes* >>> >> >> >> If answer is yes, then I will use static variable as a counter to see how >>> may rows have been added to my HBase table so far. In my use case, I >>> want >>> to write only N number of rows to a table. Is there a better way to do >>> this? Please let me know. Thanks. >>> >>> >> *--Maybe you can use Counter to track the number of rows you add to HBase, >> then you do not need to limit the reduce task as 1* >> >> >> > Counter's are not synchronized in 'real-time' : so you cant use that to > limit at addition time imo. > It is more for aggregation, not realtime messaging. > > - Mridul > -- Best Regards Jeff Zhang
