Added Cap’n Proto Input Format Support

Why it matters

This feature was created to enable ClickHouse to natively ingest data serialized with the Cap’n Proto format, which is a fast and compact binary serialization protocol. It solves the problem of integrating data pipelines and systems that use Cap’n Proto by allowing direct input without manual conversions. This adds value for users by improving data ingestion flexibility, performance, and compatibility with Cap’n Proto-based workflows.

How to use it

To use the Cap’n Proto input format in ClickHouse, specify the FORMAT CapnProto clause when using data input commands such as INSERT INTO. For example:

INSERT INTO table_name FORMAT CapnProto
<binary data here>

This tells ClickHouse to interpret the input data as Cap’n Proto encoded. Make sure the Cap’n Proto schema is compatible with the target table structure.