[FLINK-37203] Alter table comment or column comment

[ChaomingZhangCN]

https://issues.apache.org/jira/browse/FLINK-37203

[ChaomingZhangCN]

@lvyanquan @leonardBang PTAL.

[ChaomingZhangCN]

@yuxiqian Can you help review?

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity for 120 days. It will be closed in 60 days if no further activity occurs.

[lvyanquan]

Hi @ChaomingZhangCN, I apologize for not reviewing your changes in time during the past period due to other commitments. I believe this modification is reasonable. You can rebase with master (there may be conflicts), and I will review it in the coming days.

[ChaomingZhangCN]

Hi @ChaomingZhangCN, I apologize for not reviewing your changes in time during the past period due to other commitments. I believe this modification is reasonable. You can rebase with master (there may be conflicts), and I will review it in the coming days.

No problem at all, thank you for the update! I appreciate your trust in the changes. I'll rebase with master and address any conflicts. Looking forward to your feedback in the coming days.

[Copilot]

Pull request overview

This pull request implements support for altering table comments and column comments in Flink CDC, as tracked in JIRA issue FLINK-37203. The implementation introduces a new AlterTableCommentEvent schema change event and extends AlterColumnTypeEvent to carry column comments during type alterations.

Changes:

• Added new AlterTableCommentEvent class and associated serialization, visitor, and type infrastructure
• Extended AlterColumnTypeEvent to include a comments map for tracking column comments during type changes
• Updated MySQL connector to parse and emit table comment alterations and column comment changes
• Implemented comment handling in multiple sink connectors (Paimon, MaxCompute, OceanBase, Doris, Values)

Reviewed changes

Copilot reviewed 39 out of 39 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
AlterTableCommentEvent.java	New event class representing ALTER TABLE COMMENT DDL
AlterColumnTypeEvent.java	Extended to support column comments with a new comments field
AlterTableCommentEventSerializer.java	Serializer for the new AlterTableCommentEvent
SchemaChangeEventType.java	Added ALTER_TABLE_COMMENT enum value
SchemaChangeEventTypeFamily.java	Included ALTER_TABLE_COMMENT in TABLE family
AlterTableCommentEventVisitor.java	New visitor interface for table comment events
SchemaChangeEventVisitor.java	Updated to handle AlterTableCommentEvent
CustomAlterTableParserListener.java	MySQL parser updated to capture table and column comments
CustomMySqlAntlrDdlParserListener.java	Registered AlterTableParserListener
Schema.java	Added copy method to replace schema comment
SchemaUtils.java	Updated to apply AlterTableCommentEvent to schemas
SchemaMergingUtils.java	Enhanced to carry comments during schema merging
ValuesDatabase.java	Implemented table and column comment support
PaimonMetadataApplier.java	Added handler for AlterTableCommentEvent with column comment updates
MaxComputeMetadataApplier.java	Implemented table comment alteration support
OceanBaseMySQLCatalog.java	Added alterTable method for table comments
OceanBaseOracleCatalog.java	Added stub method throwing unsupported exception
DorisMetadataApplier.java	Added table comment handler
DorisSchemaChangeManager.java	Implemented alterTableComment method
StarRocksMetadataApplier.java	Added TODO comment for future implementation
IcebergMetadataApplier.java	Throws UnsupportedSchemaChangeEventException
Multiple test files	Updated expected event strings to include comments field

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[lvyanquan]

Rebased master and addressed the comments of copilot.