PIG how to count a number of rows in alias

Question

I did something like this to count the number of rows in an alias in PIG:

logs = LOAD \'log\'
logs_w_one = foreach logs generate 1 as one;
logs_group = group         


        

Answer 1

Here is a version with optimization. All the solutions above would require pig to read and write full tuple when counting, this script below just write '1'-s

DEFINE row_count(inBag, name) RETURNS result {
    X = FOREACH $inBag generate 1;
    $result = FOREACH (GROUP X ALL PARALLEL 1) GENERATE '$name', COUNT(X);
};

The use it like

xxx = row_count(rows, 'rows_count');