fixed splitting records by database from topic name

[chernser]

Summary

• Fixes grouping by database when db topic split enabled
• Fixes recording correct database in RecordConverter
• Adds integration test for the feature

Closes: #580

Checklist

Delete items not relevant to your PR:

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG
• For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

[Copilot]

Pull Request Overview

This PR fixes grouping by database when database topic splitting is enabled and ensures the correct database is recorded in the RecordConverter.

• Fixes grouping logic in ProxySinkTask to group by database instead of topic when database topic splitting is enabled
• Adds helper methods for creating/dropping databases and counting rows with specific database names
• Includes an integration test to verify the database topic splitting functionality

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
ClickHouseTestHelpers.java	Adds database creation/dropping utilities and proper resource cleanup for queries
RecordConvertorTest.java	Adds unit test for database topic splitting functionality
ClickHouseSinkTaskWithSchemaTest.java	Adds integration test for database topic splitting across multiple tenants
ClickHouseHelperClient.java	Updates table extraction methods to use correct database parameter
ProxySinkTask.java	Fixes grouping logic to use database as key when database topic splitting is enabled

Comments suppressed due to low confidence (1)

src/main/java/com/clickhouse/kafka/connect/sink/db/helper/ClickHouseHelperClient.java:422

• Missing proper indentation. The closing brace should be properly aligned with the rest of the code block.

                    table.addColumn(column);                }

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[Copilot]

This import is unused and appears to be accidentally added. The jdk.dynalink.Operation class is not used anywhere in this file.

Suggested change

import jdk.dynalink.Operation;

[Copilot]

This import is unused. The ClickHouseSinkConfig class is not referenced anywhere in this file.

Suggested change

import com.clickhouse.kafka.connect.sink.ClickHouseSinkConfig;

[Copilot]

Using System.out.println for debugging in tests is not recommended. Consider using a proper logger or removing this debug statement entirely.

Suggested change

System.out.println("actual_topic: " + actualTopic);

[Copilot]

Missing semicolon or line break between the two assertions. This should be split into two separate statements for proper formatting and readability.

Suggested change

	assertEquals(sr.size(), ClickHouseTestHelpers.countRows(chc, topic));assertTrue(ClickHouseTestHelpers.validateRows(chc, topic, sr));
	assertEquals(sr.size(), ClickHouseTestHelpers.countRows(chc, topic));
	assertTrue(ClickHouseTestHelpers.validateRows(chc, topic, sr));