http://blackproof.iteye.com/blog/1791980
data = LOAD '/production/log/{10000}/{131001,131130}' USING PigStorage(',');
data = FOREACH data GENERATE (int) $0 AS id1, (int) $2 AS id2, (long) $3AS id3, (chararray) REPLACE($4, '_', '') AS id5, (chararray) REPLACE($9, '%3B', ',') AS id6 ;