Remember that mappers are not executed in a well defined order. They can be executed in different order or even at the same time. One mapper can be run more than once.
There are two ways to get something like what you want, but the question you asked is ill-posed. First, you can adapt the input format so that it gives a different integer to each split as a key. This doesn't something like what you ask for since each mapper will get a different integer and multiply executed mappers will get the same key each time they are run. Secondly, you could use central coordination server to act as a global counter. **THIS IS A REALLY BAD IDEA** It is bad because it turns a parallel computation into a partially sequential one and because it doesn't account for the fact that mappers can be run multiple times. On Sat, Feb 5, 2011 at 4:03 AM, ANKITBHATNAGAR <abhatna...@vantage.com>wrote: > is there a way I can retain the count between mappers and increment.? >
