v.25.4New Feature

An in-memory cache for Iceberg metadata

Official CH changelog text
An in-memory cache for Iceberg metadata, which stores manifest files/list and metadata.json to speed up queries. #77156 (Han Fei).
An in-memory cache for Iceberg metadata that stores manifest files, manifest lists, and metadata.json to accelerate query performance.

Why it matters

This feature addresses the latency and overhead caused by repeatedly reading Iceberg metadata files during query planning and execution. By caching manifest files and metadata in memory, it reduces IO operations and speeds up query processing, improving overall system responsiveness and efficiency.

How to use it

The cache for Iceberg metadata is enabled automatically when querying Iceberg tables in ClickHouse. No additional configuration is required from the user to benefit from the in-memory metadata cache.

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