//sort the first column of the cogroup output and feed it to the quantiles function
EvalSpec sortedSampleSpec = new ProjectSpec(1);
EvalSpec starSpec = new StarSpec();
starSpec.setComparatorName(loSort.getSortSpec().getComparatorName());
sortedSampleSpec = sortedSampleSpec.addSpec(new SortDistinctSpec(false, starSpec));
argsList.add(sortedSampleSpec);
EvalSpec args = new GenerateSpec(argsList);
EvalSpec reduceSpec = new FuncEvalSpec(pigContext, FindQuantiles.class.getName(), args);