Hive and HCatalog Integration

The HCatalog library provides applications with a table view of the MapR-FS layer in your cluster, expanding your application's options from read/write data streams to add table operations such as get row and store row. The HCatalog library stores the metadata required for its operations in the Hive Metastore.

The hcat utility can execute any of the data definition language (DDL) commands available in Hive that do not involve launching a MapReduce job. Internally, the hcat utility passes DDL commands to the hive program. Data stored in the MapR filesystem is serialized and deserialized through InputStorageFormats and OutputStorageFormats objects for records. Fields within a record are parsed with SerDes.

Warning:

The hive-json-serde-0.2.jar JSON serializer/deserializer has not implemented a serialize() method and as a result does not function.

The WebHCat server provides a REST-like web API for HCatalog. For more information about using WebHCat, see Hive and WebHCat Integration.

This section contains the following topics: