Apache Drill vs Impala: What are the differences?

Introduction

Apache Drill and Impala are both distributed query engines that enable users to perform interactive analytics on large datasets in various data sources. While they share similarities in terms of their functionality, there are key differences between Apache Drill and Impala.

1. Query Language Support: Apache Drill supports ANSI SQL along with extensions that enable querying on non-relational data such as JSON, Parquet, Hadoop File System (HDFS), and NoSQL databases. On the other hand, Impala primarily focuses on querying structured data stored in Hadoop Distributed File System (HDFS) and Apache HBase using a SQL-like language.

2. Data Source Connectivity: Apache Drill supports a wide range of data sources including traditional databases (MySQL, PostgreSQL), file systems (HDFS, NFS), cloud storage (Amazon S3, Google Cloud Storage), HBase, and more. Impala, on the other hand, is tightly integrated with Hadoop ecosystem components and mainly focuses on querying data stored in HDFS and Apache HBase.

3. Cluster Management and Resource Allocation: Impala relies on Hadoop components like Apache Hadoop YARN for cluster management and resource allocation. Apache Drill, on the other hand, is designed to work with various cluster management systems including Apache Mesos, Hadoop YARN, and Kubernetes. This flexibility allows Apache Drill to be utilized in environments outside of the Hadoop ecosystem as well.

4. Performance Optimization: Impala operates using a code generation strategy, which compiles queries into machine code for performance. This approach results in high query execution speeds for Impala. Apache Drill, on the other hand, utilizes a runtime-generated code approach, which trades off some performance optimization for flexibility and support for dynamic schema. While this may result in slightly slower query execution speeds in some cases, Apache Drill enables querying data with evolving and changing schema.

5. Community and Development: The development and support for Apache Drill are governed by the Apache Software Foundation, ensuring an open and collaborative development process. Impala, on the other hand, is developed and maintained by Cloudera, a commercial software company. While both projects have active communities, the governance structure and ownership differ.

6. Integration with Ecosystem Tools: Apache Drill integrates well with various ecosystem tools and frameworks like Apache Superset, Apache Zeppelin, and Apache Arrow, enabling seamless data exploration and visualization. Impala integrates well with other Hadoop ecosystem components like Apache Hive and Apache HBase, providing robust data processing capabilities.

In summary, while both Apache Drill and Impala are distributed query engines with similar goals, they differ in their query language support, data source connectivity, cluster management, performance optimization approaches, development governance, and integration with ecosystem tools.