brickhouse.udf.collect
Class GroupCountUDF

java.lang.Object
  org.apache.hadoop.hive.ql.exec.UDF
      brickhouse.udf.collect.GroupCountUDF

public class GroupCountUDF
extends org.apache.hadoop.hive.ql.exec.UDF

GroupCountUDF provides a sequence number for all rows which have the same value for a particular grouping. This allows us to count how many rows are in a grouping and cap them off after a certain point.

For example, we can cap-off the number of records per ks_uid with something like select ks_uid, val, group_count(ks_uid) as rank from ( select ks_uid, val from table1 distribute by ks_uid sort by ks_uid, val ) ordered_keys where group_count( ks_uid ) < 100

Constructor Summary

GroupCountUDF()

Method Summary

Integer

evaluate(String grouping)

Methods inherited from class org.apache.hadoop.hive.ql.exec.UDF

getRequiredFiles, getRequiredJars, getResolver, setResolver

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GroupCountUDF

public GroupCountUDF()

Method Detail

evaluate

public Integer evaluate(String grouping)