puller: Support discarding unsupported DDL by setting ignore-txn-start-ts in filter. (#12287)

[ti-chi-bot]

This is an automated cherry-pick of #12287

What problem does this PR solve?

Issue Number: close #12286

What is changed and how it works?

1. DDLs can be skipped in the ddlPuller by setting IgnoreTxnStartTs in the filter configuration. It is also helpful when we need to skip DDLs that cannot be handled by TiCDC.

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)

1. create a changefeed.
2. execute follow ddl upstream

create table a (a bigint primary key, b int);
create table b like a;
rename table a to c, b to a, c to b;

3. changefeed meets the following error:

> ./cdc cli changefeed list
[
  {
    "id": "test",
    "namespace": "default",
    "summary": {
      "state": "warning",
      "tso": 460194169340821515,
      "checkpoint": "2025-08-18 15:17:19.441",
      "error": {
        "time": "2025-08-18T15:17:20.493361+08:00",
        "addr": "127.0.0.1:8300",
        "code": "CDC:ErrHandleDDLFailed",
        "message": "[CDC:ErrHandleDDLFailed]handle ddl failed, query: rename table a to c, b to a, c to b, startTs: 460194169353928710. If you want to skip this DDL and continue with replication, you can manually execute this DDL downstream. Afterwards, add `ignore-txn-start-ts=[460194169353928710]` to the changefeed in the filter configuration.: [CDC:ErrSnapshotTableNotFound]table 112 not found in schema snapshot"

4. Adjust changefeed filter config file cf.toml, add the ignore-txn-start-ts=[460194169353928710] to filter.

[filter]
ignore-txn-start-ts = [460194169353928710]

5. Update chagnefeed with cf.toml.

./cdc cli changefeed update -c test --config=cf.toml 

6. resume changefeed, chagnefeed resume to normal.

> ./cdc cli changefeed list
[
  {
    "id": "test",
    "namespace": "default",
    "summary": {
      "state": "normal",
      "tso": 460194185921429508,
      "checkpoint": "2025-08-18 15:18:22.691",
      "error": null
    }
  }
]

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

Support discarding unsupported DDL by setting `ignore-txn-start-ts` in filter.

[ti-chi-bot]

@asddongmen This PR has conflicts, I have hold it.
Please resolve them or ask others to resolve them, then comment /unhold to remove the hold label.

[ti-chi-bot]

@ti-chi-bot: ## If you want to know how to resolve it, please read the guide in TiDB Dev Guide.

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[gemini-code-assist]

Summary of Changes

Hello @ti-chi-bot, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the DDL (Data Definition Language) filtering capabilities within the ddlPuller component. The primary goal is to provide users with a mechanism to explicitly ignore specific DDL operations based on their transaction start timestamp. This new functionality is crucial for scenarios where TiCDC encounters DDLs it cannot process, allowing users to configure the system to skip these problematic DDLs and prevent changefeeds from entering a warning or error state. The changes involve modifying the DDL filtering interface to accept transaction timestamps and updating the DDL puller to utilize this new filtering criterion, along with refined handling for multi-table DDLs.

Highlights

• Enhanced DDL Filtering: The core filtering logic for DDLs (ShouldDiscardDDL) now accepts a transaction start timestamp (startTs), enabling more granular control over which DDLs are processed or ignored.
• New ignore-txn-start-ts Configuration: A new configuration option, ignore-txn-start-ts, has been introduced, allowing users to specify a list of transaction timestamps for DDLs that should be explicitly discarded by the ddlPuller. This is particularly useful for skipping DDLs that TiCDC cannot handle, preventing changefeed errors.
• DDL Puller Integration: The DDL puller's handleJob function has been updated to leverage this new startTs parameter, ensuring that DDLs are filtered not only by type, schema, and table but also by their specific transaction timestamp.
• Refined Multi-Table DDL Processing: Improved handling for complex DDLs like CREATE TABLES and RENAME TABLE allows the filter to apply to individual tables within these multi-table operations, providing more precise control over DDL replication.

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[gemini-code-assist]

Code Review

This pull request introduces a feature to discard unsupported DDLs by specifying their start-ts in the changefeed filter configuration. This is a useful feature for unblocking replication when encountering problematic DDLs. The changes span across the DDL puller and filter logic, with corresponding updates to tests.

However, the pull request contains several unresolved merge conflicts, which makes the code uncompilable. These must be resolved. Additionally, there is a compilation error in cdc/puller/ddl_puller.go due to usage of an undefined variable. These critical issues need to be addressed before this PR can be merged.

[asddongmen]

/test pull-dm-integration-test

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: asddongmen

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