Can you explain the internal architecture of the Athena system?

Amazon Athena is a serverless service for interactive data analysis that allows you to run SQL queries on data stored in Amazon S3 without managing infrastructure.

The internal architecture of Athena is based on the following components:

• SQL Queries: Users send SQL queries via console, API, or client.
• Query Planner: Athena analyzes the query, constructs an execution plan, and optimizes it.
• Execution Engine: Athena uses a Presto-based engine (an open-source distributed SQL engine) that executes queries in parallel on a cluster.
• Data Access: Data is stored in S3 in various formats (CSV, JSON, Parquet, etc.). Athena reads data directly from S3 without loading it into a separate storage.
• Metadata: Metadata about tables and schemas is stored in AWS Glue Data Catalog or the built-in Athena catalog.

Thus, Athena's architecture is a serverless solution that scales automatically, uses Presto for distributed query processing, and works directly with data in S3, providing flexibility and cost-effectiveness.