Get Started with UDFs

Before you can write UDFs for your Impala queries, you must install the Impala development package that contains header and build configuration files and download the sample source code.

The development package provides a header file that is required to develop UDFs and UDAFs. The header contains the types that must be used and the FunctionContext object. This object is the interface object between the UDF or UDAF and the Impala process. You can access the header in /usr/include/impala_udf/udf.h

The sample source code provides sample files that you can view to see the declarations required to write UDFs and UDAFs, and sample source code used to create a simple UDF and UDAF example.

After you have installed the development package and sample source code, you can build the samples to create an environment that you can use to write your UDFs and UDAFs. Once you have completed your UDF or UDAF, you can deploy it.

Complete the following steps to create UDFs and UDAFs for use with Impala: