enhancement(clickhouse sink): Add ArrowStream format

[benjamin-awd]

Summary

This PR adds support for the ArrowStream format to Clickhouse.

Vector configuration

 clickhouse:
    type: clickhouse
    inputs: [normalize]
    database: mydatabase
    table: logs
    endpoint: ${CLICKHOUSE_HOST}
    format: arrow_stream
    batch_encoding:
      codec: arrow_stream
      allow_nullable_fields: true

How did you test this PR?

Ran against local Clickhouse instance, integration tests

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Closes Add ArrowStream format to Clickhouse sink #24074

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[thomasqueirozb]

All my comments here are regarding improvements. This is very nice work and should work as is, thanks a lot!

[akutta]

2025-12-15T13:37:08.641679Z ERROR vector::topology::builder: Configuration error. error=Sink "clickhouse": Failed to fetch schema for logs.logs: Failed to fetch schema from provider: Failed to convert column 'other_attributes': Unknown ClickHouse type 'JSON'. This type cannot be automatically converted.. internal_log_rate_limit=false

Per the docs; this is a limitation of the Arrow format:

Unsupported Arrow data types:

FIXED_SIZE_BINARY
JSON
UUID
ENUM.

So it's not fully backwards compatible with the JSON encoder. Would make sense to call this out in the documentation.

[thomasqueirozb]

Thanks! Only a couple of small nits and small improvements but this should be pretty much good to go!