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]

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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. It introduces the ability to discard specific DDL operations based on their transaction start timestamp. This new functionality allows users to configure the system to ignore problematic DDLs that might otherwise cause replication errors, such as complex RENAME TABLE statements. By providing a mechanism to skip these unsupported DDLs, the changefeed can continue replicating data without interruption, improving the overall robustness and resilience of the data synchronization process.

Highlights

• Enhanced DDL Filtering: The ShouldDiscardDDL function in the filter package now accepts a startTs (transaction start timestamp) parameter, enabling more granular control over which DDL operations are discarded.
• Integration of Start Timestamp in DDL Puller: The DDL puller now passes the transaction start timestamp to the DDL filter, allowing it to skip specific DDLs that might cause issues, such as complex RENAME TABLE operations that TiCDC cannot handle.
• New Configuration for Ignoring DDLs: A new configuration option, ignore-txn-start-ts, has been introduced. Users can specify a list of transaction start timestamps for DDLs that should be explicitly ignored by the changefeed, providing a mechanism to recover from DDL-related errors.
• Improved Test Coverage: New unit tests have been added to verify that DDLs can be successfully discarded based on their transaction start timestamp, ensuring the reliability of the new filtering mechanism.

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[gemini-code-assist]

Code Review

This pull request introduces a mechanism to discard unsupported DDL statements by specifying their transaction start timestamp in the filter configuration. The changes correctly propagate the startTs to the ShouldDiscardDDL function and update the filter logic to check against a list of ignored timestamps. The implementation is consistent across the affected components, and the new functionality is well-tested, including a unit test for skipping a RENAME TABLE DDL that would otherwise fail. The code quality is good, and the changes effectively address the problem of handling DDLs that are not supported by TiCDC. I have no further suggestions for improvement.

[codecov]

Codecov Report

❌ Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (release-8.5@4d578e9). Learn more about missing BASE report.

Additional details and impacted files

Components	Coverage Δ
cdc	59.5411% <0.0000%> (?)
dm	50.0519% <0.0000%> (?)
engine	53.2110% <0.0000%> (?)

Flag	Coverage Δ
unit	55.1188% <91.6666%> (?)

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