feat(connectors): Clickhouse Sink Connector

[kriti-sc]

Which issue does this PR close?

Closes #2539

Rationale

Clickhouse is a real-time data analytics engine, and very popular in modern analytics architectures.

What changed?

This PR introduces a Clickhouse Sink Connector that enables writing data from Iggy to Clickhouse.

The Clickhouse writing logic is heavily inspired by the official Clickhouse Kafka Connector.

Local Execution

• Produced messages 30456 + 29060 rows with schema user_id: String, user_type: u8, email: String, source: String, state: String, created_at: DateTime, message: String using sample data producer.
• Consumed messages using the Clickhouse sink and into the particular Clickhouse table.
• Verified schema and number of rows in Clickhouse.
• Added unit tests and e2e tests, both passing.

Images 1&2: Produced 30456 + 29060 rows into Iggy in two batches
Image 3: Verified schema and number of rows in Clickhouse

AI Usage

1. Which tools? (e.g., GitHub Copilot, Claude, ChatGPT) Claude Code
2. Scope of usage? (e.g., autocomplete, generated functions, entire implementation) generated functions
3. How did you verify the generated code works correctly? Manual testing by producing data into Iggy and then running the sink and verifying insertion into Clickhouse, unit tests and e2e tests for different Clickhouse insert configurations.
4. Can you explain every line of the code if asked? Yes

[codecov]

Codecov Report

❌ Patch coverage is 83.05322% with 363 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.44%. Comparing base (7b2db33) to head (e072eca).

Files with missing lines	Patch %	Lines
...ore/connectors/sinks/clickhouse_sink/src/binary.rs	83.65%	125 Missing and 55 partials ⚠️
...ore/connectors/sinks/clickhouse_sink/src/schema.rs	76.92%	30 Missing and 75 partials ⚠️
...ore/connectors/sinks/clickhouse_sink/src/client.rs	73.94%	58 Missing and 10 partials ⚠️
core/connectors/sinks/clickhouse_sink/src/lib.rs	97.27%	3 Missing and 1 partial ⚠️
core/connectors/sinks/clickhouse_sink/src/sink.rs	60.00%	4 Missing ⚠️
core/connectors/sinks/clickhouse_sink/src/body.rs	98.80%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             master    #2886       +/-   ##
=============================================
- Coverage     73.98%   45.44%   -28.55%     
  Complexity      937      937               
=============================================
  Files          1263     1266        +3     
  Lines        132810   117777    -15033     
  Branches     108444    93458    -14986     
=============================================
- Hits          98257    53520    -44737     
- Misses        31454    61391    +29937     
+ Partials       3099     2866      -233     

Components	Coverage Δ
Rust Core	38.29% <83.05%> (-36.25%)	⬇️
Java SDK	62.44% <ø> (ø)
C# SDK	71.40% <ø> (-0.71%)	⬇️
Python SDK	91.65% <ø> (ø)
PHP SDK	84.29% <ø> (ø)
Node SDK	91.22% <ø> (+0.09%)	⬆️
Go SDK	40.14% <ø> (ø)

Files with missing lines	Coverage Δ
core/connectors/sinks/clickhouse_sink/src/body.rs	98.80% <98.80%> (ø)
core/connectors/sinks/clickhouse_sink/src/lib.rs	97.27% <97.27%> (ø)
core/connectors/sinks/clickhouse_sink/src/sink.rs	60.00% <60.00%> (ø)
...ore/connectors/sinks/clickhouse_sink/src/client.rs	73.94% <73.94%> (ø)
...ore/connectors/sinks/clickhouse_sink/src/schema.rs	76.92% <76.92%> (ø)
...ore/connectors/sinks/clickhouse_sink/src/binary.rs	83.65% <83.65%> (ø)

... and 378 files with indirect coverage changes

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[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs.

If you need a review, please ensure CI is green and the PR is rebased on the latest master. Don't hesitate to ping the maintainers - either @core on Discord or by mentioning them directly here on the PR.

Thank you for your contribution!

[hubcio]

overall good direction, just needs a little bit polishing

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs.

If you need a review, please ensure CI is green and the PR is rebased on the latest master. Don't hesitate to ping the maintainers - either @core on Discord or by mentioning them directly here on the PR.

Thank you for your contribution!

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs.

If you need a review, please ensure CI is green and the PR is rebased on the latest master. Don't hesitate to ping the maintainers - either @core on Discord or by mentioning them directly here on the PR.

Thank you for your contribution!

[kriti-sc]

/ready

[hubcio]

i think after you fix these we can merge @kriti-sc

[kriti-sc]

/ready

[atharvalade]

One smaller thing I noticed but left out as non-critical: the README still says retries use "a fixed delay... not exponential backoff" and that MATERIALIZED columns get the 0x01 prefix byte, both of which the code no longer does. Worth changing I believe

[kriti-sc]

/ready