Cascading-Hive is an integration between Apache Hive and Cascading. It currently has the following major features:
- running Hive queries within a Cascade
- reading from Hive tables within a Cascading Flow
- writing/creating Hive tables from a Cascading Flow
- writing/creating partitioned Hive tables from a Cascading Flow
- deconstructing a Hive view into Taps
The demo sub-directory contains applications that demonstrate those
features.
The code will pick up the configuration for a remote Hive MetaStore automatically, as long as it is present in your hive or hadoop configuration files.
Cascading-Hive works with hive-0.10+. When using the maven dependency you have
to specify the version of Hive you are using as a runtime dependency yourself.
This is done to avoid classpath issues with the various Hadoop and Hive
distributions in existence. See the demo project for an example.
To install cascading-hive into your local maven repository do this:
> gradle install
Please note that the support for Hive views is currently limited since views
pretend to be a resource or a Tap in Cascading terms, but are actually
computation. It is currently not possible to read from a Hive View within a
Cascading Flow. To work around this, you can create a table in Hive instead, and
read from that within your Cascading Flow. This restriction might change in the
future.
Please also note also that Hive relies on the hadoop command being present in
your PATH when it executes the queries on the Hadoop cluster.