9d2f8043_Troubleshooting_Impala__Recommendation
[Symptom] Queries return incorrect results. [Explanation] Impala metadata may be outdated after changes are performed in Hive. [Recommendation] 
Where possible, use the appropriate Impala statement (INSERT, LOAD DATA, CREATE TABLE, ALTER TABLE, COMPUTE STATS, and so on) rather than switching back and forth between Impala and Hive. Impala automatically broadcasts the results of DDL and DML operations to all Impala nodes in the cluster, but does not automatically recognize when such changes are made through Hive. After inserting data, adding a partition, or other operation in Hive, refresh the metadata for the table as described in REFRESH Statement.
Troubleshooting Impala