The major components of a Pig execution environment are :
Pig Scripts : They are written in Pig Latin using built-in operators and UDFs, and submitted to the execution environment.
Parser : Completes type checking and checks the syntax of the script. The output of the parser is a Directed Acyclic Graph (DAG).
Optimizer : Performs optimization using merge, transform, split, etc. Optimizer aims to reduce the amount of data in the pipeline.
Compiler : Converts the optimized code into MapReduce jobs automatically.
Execution Engine : MapReduce jobs are submitted to execution engines to generate the desired results.
