Major Description
Macro used to dedup (de-duplicate) a table, based on a key or keys and an ordering (typically a date updated field).
One thing to consider - the implementation relies on the ExtremalTupleByNthField UDF in PiggyBank. I've added it to the test dependencies in order for the test to run. While I feel that anyone using Pig typically has PiggyBank in the classpath, this might not be true - do we have an alternative? (maybe adding it to the jarjar?)
The macro's definition looks as follows:
DEFINE dedup(relation, row_key, order_field) returns out {
relation - relation to dedup
row_key - field(s) for group by
order_field - the field for ordering (to find the most recent record)