schemastore: fix exchange partition name unquoting by lidezhu · Pull Request #4449 · pingcap/ticdc

lidezhu · 2026-03-12T07:17:19Z

What problem does this PR solve?

Issue Number: close #4450

What is changed and how it works?

This pull request resolves a bug in the handling of EXCHANGE PARTITION DDL statements where partition names, especially those containing escaped backticks, were not being unquoted correctly. By implementing a robust UnquoteName utility and applying it to the relevant DDL parsing paths, the change ensures accurate processing of schema changes, preventing potential data inconsistencies or errors in schema replication.

Highlights

New Utility Function: Introduced a new UnquoteName utility function in the pkg/common package to correctly handle MySQL identifier unquoting, including the unescaping of doubled backticks.
DDL Parsing Fix: Integrated the UnquoteName function into the DDL handling logic for EXCHANGE PARTITION statements within the schemastore and event packages, ensuring proper parsing of partition names that may contain escaped backticks.
Improved Test Coverage: Updated existing unit tests and added new dedicated unit tests for the UnquoteName function to validate its correctness across various scenarios, including unquoted, quoted, and quoted names with escaped backticks.

Check List

Tests

Unit test
Integration test
Manual test (add detailed scripts or steps below)
No code

Questions

Will it cause performance regression or break compatibility?

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

Release note

Please refer to [Release Notes Language Style Guide](https://pingcap.github.io/tidb-dev-guide/contribute-to-tidb/release-notes-style-guide.html) to write a quality release note.

If you don't think this PR needs a release note then fill it with `None`.

gemini-code-assist · 2026-03-12T07:17:24Z

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Reviewing files that changed from the base of the PR and between d37d22f and ae1f944.

📒 Files selected for processing (5)

logservice/schemastore/persist_storage_ddl_handlers.go
logservice/schemastore/persist_storage_test.go
pkg/common/event/util.go
pkg/common/table_info.go
pkg/common/table_info_test.go

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Commit unit tests in branch ldz/fix-exchange-partion0312

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lidezhu · 2026-03-12T07:26:52Z

/gemini summary

gemini-code-assist · 2026-03-12T07:27:07Z

Summary of Changes

This pull request resolves a bug in the handling of EXCHANGE PARTITION DDL statements where partition names, especially those containing escaped backticks, were not being unquoted correctly. By implementing a robust UnquoteName utility and applying it to the relevant DDL parsing paths, the change ensures accurate processing of schema changes, preventing potential data inconsistencies or errors in schema replication.

Highlights

New Utility Function: Introduced a new UnquoteName utility function in the pkg/common package to correctly handle MySQL identifier unquoting, including the unescaping of doubled backticks.
DDL Parsing Fix: Integrated the UnquoteName function into the DDL handling logic for EXCHANGE PARTITION statements within the schemastore and event packages, ensuring proper parsing of partition names that may contain escaped backticks.
Improved Test Coverage: Updated existing unit tests and added new dedicated unit tests for the UnquoteName function to validate its correctness across various scenarios, including unquoted, quoted, and quoted names with escaped backticks.

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Changelog

logservice/schemastore/persist_storage_ddl_handlers.go
- Replaced manual backtick removal with a call to common.UnquoteName for parsing partition names in EXCHANGE PARTITION DDLs.
logservice/schemastore/persist_storage_test.go
- Modified the TestBuildPersistedDDLEventEscapesIdentifiers test case to use a partition name with an escaped backtick (p``0), aligning with the new unquoting logic.
pkg/common/event/util.go
- Replaced manual backtick removal with a call to common.UnquoteName for parsing partition names in EXCHANGE PARTITION DDLs within the DDL2Job function.
pkg/common/table_info.go
- Added a new public function UnquoteName that removes one layer of MySQL identifier quoting and unescapes doubled backticks.
pkg/common/table_info_test.go
- Added a new test file table_info_test.go containing TestUnquoteName with test cases for unquoted, quoted, and quoted with escaped backtick scenarios to validate the new UnquoteName function.

Activity

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wk989898 · 2026-03-12T07:47:57Z


 		assert.Equal(t,
-			"ALTER TABLE `part``db`.`pt``x` EXCHANGE PARTITION `p0` WITH TABLE `normal``db`.`normal``t` WITHOUT VALIDATION",
+			"ALTER TABLE `part``db`.`pt``x` EXCHANGE PARTITION `p``0` WITH TABLE `normal``db`.`normal``t` WITHOUT VALIDATION",


wk989898 · 2026-03-12T07:49:20Z

 }

+// UnquoteName removes one layer of MySQL identifier quoting and unescapes doubled backticks.
+func UnquoteName(name string) string {


I think there exists a similar function, and the function is duplicate

I guess 😆

wk989898 · 2026-03-12T07:51:04Z

 	t.Run("exchange partition", func(t *testing.T) {
 		job := buildExchangePartitionJobForTest(100, 200, 300, "pt`x", []int64{301}, 1000)
-		job.Query = "ALTER TABLE `ignored`.`ignored` EXCHANGE PARTITION `p0` WITH TABLE `ignored2`.`ignored2` WITHOUT VALIDATION"
+		job.Query = "ALTER TABLE `ignored`.`ignored` EXCHANGE PARTITION `p``0` WITH TABLE `ignored2`.`ignored2` WITHOUT VALIDATION"


Is it equal to p0?

No. It is p``0, this pr is to avoid corrupting names like this.

ti-chi-bot · 2026-03-12T08:19:00Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: tenfyzhong, wk989898

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ti-chi-bot · 2026-03-12T08:19:02Z

[LGTM Timeline notifier]

Timeline:

2026-03-12 07:41:00.740562232 +0000 UTC m=+508692.252619893: ☑️ agreed by tenfyzhong.
2026-03-12 08:19:01.718396771 +0000 UTC m=+510973.230454442: ☑️ agreed by wk989898.

close #4450 (cherry picked from commit 8a61ab3) Signed-off-by: tenfyzhong <tenfy@tenfy.cn>

close #4450

lidezhu · 2026-06-08T14:39:48Z

/run-cherry-picker

ti-chi-bot · 2026-06-08T14:40:17Z

In response to a cherrypick label: new pull request created to branch release-8.5: #5247.

close #4450

schemastore: fix exchange partition

ae1f944

ti-chi-bot Bot added do-not-merge/needs-linked-issue release-note Denotes a PR that will be considered when it comes time to generate release notes. labels Mar 12, 2026

ti-chi-bot Bot added the size/M Denotes a PR that changes 30-99 lines, ignoring generated files. label Mar 12, 2026

lidezhu changed the title ~~schemastore: fix exchange partition~~ schemastore: fix exchange partition name unquoting Mar 12, 2026

ti-chi-bot Bot removed the do-not-merge/needs-linked-issue label Mar 12, 2026

tenfyzhong approved these changes Mar 12, 2026

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ti-chi-bot Bot added needs-1-more-lgtm Indicates a PR needs 1 more LGTM. approved labels Mar 12, 2026

wk989898 reviewed Mar 12, 2026

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wk989898 approved these changes Mar 12, 2026

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ti-chi-bot Bot added lgtm and removed needs-1-more-lgtm Indicates a PR needs 1 more LGTM. labels Mar 12, 2026

ti-chi-bot Bot merged commit 8a61ab3 into master Mar 12, 2026
12 checks passed

ti-chi-bot Bot deleted the ldz/fix-exchange-partion0312 branch March 12, 2026 09:30

tenfyzhong pushed a commit that referenced this pull request Mar 18, 2026

schemastore: fix exchange partition name unquoting (#4449)

8669eff

close #4450 (cherry picked from commit 8a61ab3) Signed-off-by: tenfyzhong <tenfy@tenfy.cn>

tenfyzhong pushed a commit that referenced this pull request Mar 18, 2026

schemastore: fix exchange partition name unquoting (#4449)

1540a05

close #4450

tenfyzhong pushed a commit that referenced this pull request Mar 25, 2026

schemastore: fix exchange partition name unquoting (#4449)

0dc5e04

close #4450

lidezhu added the needs-cherry-pick-release-8.5 Should cherry pick this PR to release-8.5 branch. label Jun 8, 2026

ti-chi-bot mentioned this pull request Jun 8, 2026

schemastore: fix exchange partition name unquoting (#4449) #5247

Merged

ti-chi-bot Bot pushed a commit that referenced this pull request Jun 9, 2026

schemastore: fix exchange partition name unquoting (#4449) (#5247)

5da01a4

close #4450

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lidezhu commented Mar 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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lidezhu commented Mar 12, 2026 •

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