ticdc: MySQL sink dispatcher routing

[a-cong]

What problem does this PR solve?

Issue Number: close #12434

What is changed and how it works?

• Extended the dispatchers field (currently used for mq sinks https://docs.pingcap.com/tidb/stable/ticdc-sink-to-kafka/#topic-dispatchers) to support schema/table routing for mysql sinks. The config looks like this:

[[sink.dispatchers]]
matcher = ["source_db1.*"]
schema = "dest_db1"
table = "{table}"

[[sink.dispatchers]]
matcher = ["source_db2.*"]
schema = "source_db2"
table = "{table}"

• The Dispatcher interface routes the given sourceSchema, sourceTable to targetSchema, targetTable. SinkRouter wraps the dispatchers
• Added TargetSchema and TargetTable fields to TableName struct in cdc/model/sink.go, which are populated when the sink router is defined. This is handled in 2 ways - for tables that already exist when the changefeed is created/started, the fields are added to the existing snapshot of the schema. For tables that are created later, the fields are added to the new table before the new snapshot is saved
• Use TargetSchema and TargetTable for the USE statement in mysql_ddl_sink.go, and in new method QuoteSinkString() which is called to construct mysql DMLs in pkg/sqlmodel/multirow.go and pkg/sqlmodel/row_change.go
• Use FetchDDLTables and RenameDDLTable from the dm parser pkg to rewrite DDLs after they are constructed if the schema router is specified. FetchDDLTables returns all of the tables referenced in the DDL in the order that they appear in the DDL. We then use the schema router to map each source schema to its target schema and pass this list of tables to RenameDDLTable

Check List

Tests

• Unit test
• Manual test - tested in our local development environment

Questions

Will it cause performance regression or break compatibility?

No, the additional latency for DDL rewrites should be minimal compared to barrier ts, and there should not be compatibility issues since this is a new feature

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

Yes, this is a new feature for mysql sinks, will need to update https://docs.pingcap.com/tidb/stable/ticdc-sink-to-mysql/

Release note

Support schema and table routing for mysql-compatible sinks by extending the dispatchers config

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Hi @a-cong. Thanks for your PR.

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All committers have signed the CLA.

[wk989898]

Could you provide a case to demonstrate this feature？ It's better to add an integration test to cover it.

[wk989898]

/ok-to-test

[codecov[bot]]

Codecov Report

:x: Patch coverage is 64.51613% with 132 lines in your changes missing coverage. Please review. :warning: Please upload report for BASE (release-8.5@df4a904). Learn more about missing BASE report.

Additional details and impacted files

Components	Coverage Δ
cdc	57.8408% <0.0000%> (?)
dm	48.6677% <0.0000%> (?)
engine	50.6998% <0.0000%> (?)

Flag	Coverage Δ
unit	53.4418% <64.5161%> (?)

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[a-cong]

Could you provide a case to demonstrate this feature？ It's better to add an integration test to cover it.

I added an integration test in sink_routing, please take a look. I fixed the rest of the tests but pull-dm-integration-test is still failing with a mysql connection error and I'm not sure why - is it related to my changes?

[3AceShowHand]

/retest

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: 3AceShowHand Once this PR has been reviewed and has the lgtm label, please assign benmeadowcroft for approval. For more information see the Code Review Process. Please ensure that each of them provides their approval before proceeding.

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[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2025-12-15 13:57:23.304563268 +0000 UTC m=+1481388.118340840: :ballot_box_with_check: agreed by 3AceShowHand.

[a-cong]

/retest

[a-cong]

/retest

[a-cong]

/retest

[wk989898]

/test all