Beyond JSON blobs: Implementing the VARIANT data type in Apache Iceberg V3

This article introduces Apache Iceberg V3's VARIANT data type for efficiently storing and querying semi-structured JSON data in data lakes, demonstrated on Amazon EMR Serverless.

• VARIANT uses binary encoding and columnar shredding instead of storing JSON as text strings
• Queries access only needed fields without deserializing entire JSON documents
• Reduces storage footprint through efficient compression and query processing time
• Create Iceberg V3 tables with VARIANT columns using format-version=3
• Use parse_json() to convert JSON strings to binary VARIANT format at write time
• Extract fields with variant_get() function using JSON path syntax
• Supports nested object access, array indexing, and type-specific extraction
• Ideal for IoT sensors, clickstream analytics, and log data with evolving schemas
• Amazon EMR Serverless 8.0 includes native Iceberg V3 and VARIANT support
• Part 1 covers basics; Part 2 will benchmark performance against string storage

VARIANT bridges JSON flexibility with columnar performance, enabling efficient semi-structured data management without predefined schemas.