Impala is a massively parallel processing (MPP) SQL query engine for Hadoop that enables low-latency queries directly on data stored in Apache Hadoop Distributed File System (HDFS). It allows users to run SQL queries on large datasets stored in HDFS and returns results in seconds without moving data between systems or loading it into a data warehouse. Impala supports most of the SQL-92 standard and can query data where it resides in HDFS, eliminating the need to load it into another database.