http://docs.aws.amazon.com/ElasticMapReduce/latest/DeveloperGuide/ami-versions-supported.html
https://wiki.apache.org/pig/RunPig https://wiki.apache.org/pig/PigUserCookbook https://pig.apache.org/docs/r0.7.0/piglatin_ref2.html#FOREACH
http://stackoverflow.com/questions/24747489/invalid-scalar-projection-error-after-doing-a-join-and-then-filter-in-pig http://stackoverflow.com/questions/10423484/how-can-i-remove-duplicates-with-constraints-in-pig http://stackoverflow.com/questions/23900796/in-apache-pig-select-distinct-rows-based-on-a-single-column http://stackoverflow.com/questions/17656012/pig-get-top-n-values-per-group http://stackoverflow.com/questions/14277926/merging-two-datasets-in-pig
http://blog.mortardata.com/post/88485590701/13-things-you-didnt-know-you-could-do-with-pig