CDH 5 Beta 2 and later versions include Hive version 0.12. Upgrading to Hive 0.12 requires a metastore schema upgrade.

  Warning:

You must upgrade the metastore schema before starting the new version of Hive. Failure to do so may result in metastore corruption.

schemaTool -d <dbType> -upgradeSchema

The following are additional incompatible changes between CDH 4.x and CDH 5:

• Upgrading Hive from CDH 4.x to CDH 5 requires several manual steps. Please be sure to follow the upgrade guide closely. See Upgrading Hive.
• The CDH 4 JDBC client is not compatible with CDH 5 HiveServer2. JDBC applications connecting to the CDH 5 HiveServer2 will require the CDH 5 JDBC client driver.
• JDBC applications will require the newer CDH 5 JDBC packages in order to connect to HiveServer2. You do not need to recompile applications for this change.
• Because of security and concurrency issues, the original Hive server (HiveServer1) and the Hive command-line interface (CLI) are deprecated in current versions of CDH 5 and will be removed in a future release. Cloudera strongly encourages you to migrate to HiveServer2 and Beeline as soon as possible.
• CDH 5 Hue will not work with HiveServer2 from CDH 4.
• The npath function has been removed.
• Cloudera recommends that custom ObjectInspectors created for use with custom SerDes have a no-argument constructor in addition to their normal constructors, for serialization purposes. See HIVE-5380 for more details.
• The SerDe interface has been changed which requires the custom SerDe modules to be reworked.
• The decimal data type format has changed as of CDH 5 Beta 2 and is not compatible with CDH 4.
• From CDH 5 Beta 2 onwards, the Parquet SerDe is part of the Hive package. The SerDe class name has changed as a result. However, there is a wrapper class for backward compatibility, so any existing Hive tables created with the Parquet SerDe will continue to work with CDH 5 Beta 2 and later Hive versions.