Mayank Lahiri, a summer intern here at Facebook, wrote up some usage docs on a few of the new functions he added. I'm linking them here in case others find them useful.
http://wiki.apache.org/hadoop/Hive/StatisticsAndDataMining He also wrote up some notes on the overall process of writing your own UDAF: http://wiki.apache.org/hadoop/Hive/GenericUDAFCaseStudy This also includes some notes from Arvind Prabhakar on interface evolution for the UDAF resolver. JVS
