hive mapreduce

Hive is a data warehousing tool that provides SQL-like interface to process and analyze structured data. Hive uses MapReduce as its underlying processing engine to execute queries on large datasets stored in Hadoop Distributed File System (HDFS).

When a query is submitted to Hive, it is first converted into a series of MapReduce jobs that are executed on the Hadoop cluster. Hive uses the MapReduce framework to distribute the data processing across multiple nodes in the cluster, which helps to achieve high scalability and fault-tolerance.

The MapReduce jobs generated by Hive consist of two parts: a map function and a reduce function. The map function processes input data in parallel across multiple nodes in the cluster, and produces intermediate key-value pairs. The reduce function then aggregates these intermediate results to produce a final output.

Hive also provides a number of built-in functions and operators that can be used in queries to perform various data processing and analysis tasks. These functions include aggregation functions like SUM, COUNT, AVG, and MAX, as well as filtering functions like WHERE and GROUP BY.

Overall, Hive MapReduce provides a powerful and flexible way to process and analyze large datasets in Hadoop, using familiar SQL-like syntax.