fix(ddl): wait running add index before CREATE TABLE LIKE #3863

wlwilliamx · 2025-12-31T09:55:35Z

What problem does this PR solve?

Issue Number: close #3832

What is changed and how it works?

Fix downstream schema inconsistency for CREATE TABLE ... LIKE ... when the referenced table has a long-running ADD INDEX that is still running/queueing in downstream TiDB. In this case, CREATE TABLE b LIKE a may copy the current downstream schema of a before the index becomes visible, causing b to miss the index.

This PR makes CREATE TABLE ... LIKE ... wait for any running async ADD INDEX on the referenced table before executing the CREATE TABLE ... LIKE ....

Detect CREATE TABLE ... LIKE ... in schemastore when building DDLEvent, extract the referenced table, and populate BlockedTableNames with that referenced table.
Adjust mysql/TiDB sink behavior so CREATE TABLE is eligible for async-DDL waiting logic; for normal create table (no LIKE), this is a no-op because BlockedTableNames is empty. For CREATE TABLE ... LIKE ..., it triggers waiting on the referenced table’s running ADD INDEX job.

Check List

Tests

Unit test
Integration test
Manual test

Questions

Will it cause performance regression or break compatibility?

None

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

None

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 · 2025-12-31T09:55:52Z

Summary of Changes

Hello @wlwilliamx, 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 addresses a critical schema consistency problem in TiCDC where a CREATE TABLE ... LIKE ... statement might not correctly replicate the schema of a source table if that source table is undergoing an asynchronous ADD INDEX operation. The changes ensure that such CREATE TABLE operations will now pause and wait for any in-progress index additions on the referenced table to complete, guaranteeing that the newly created table accurately reflects the complete schema, including all indexes, of its source. This prevents potential data integrity issues and ensures reliable schema replication.

Highlights

Schema Inconsistency Fix: Resolves an issue where CREATE TABLE ... LIKE ... could lead to schema inconsistencies if the referenced table had a long-running ADD INDEX operation that was not yet visible.
Referenced Table Detection: Implements logic to detect CREATE TABLE ... LIKE ... statements, identify the referenced table, and populate BlockedTableNames in the DDL event to trigger waiting.
Async DDL Waiting for CREATE TABLE: Modifies the sink behavior to allow CREATE TABLE statements (specifically CREATE TABLE ... LIKE ... when a referenced table is blocked) to wait for pending async DDL operations on the referenced table.
Integration Test Enhancement: Adds an integration test to validate that CREATE TABLE ... LIKE ... correctly waits for and inherits indexes from the source table, ensuring the fix works as expected.

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Code Review

This pull request effectively addresses the schema inconsistency issue with CREATE TABLE ... LIKE ... by ensuring it waits for any ongoing ADD INDEX operations on the referenced table. The approach of identifying the referenced table in the schemastore and adjusting the sink's waiting logic is sound. The changes are well-supported by both unit and integration tests, which provides good confidence in the fix. I have one minor suggestion to improve code readability.

logservice/schemastore/persist_storage_ddl_handlers.go

wlwilliamx · 2025-12-31T10:20:05Z

/retest

wlwilliamx · 2025-12-31T10:20:15Z

/test all

wlwilliamx · 2026-01-04T16:05:18Z

/test all

wlwilliamx · 2026-01-05T04:45:18Z

/test pull-cdc-mysql-integration-light

wlwilliamx · 2026-01-05T04:45:24Z

/test pull-cdc-mysql-integration-heavy

wlwilliamx · 2026-01-05T08:32:12Z

/test all

wlwilliamx · 2026-01-05T10:44:00Z

/retest

wlwilliamx · 2026-01-06T08:11:43Z

/test all

wlwilliamx · 2026-01-06T12:02:28Z

/retest

wlwilliamx · 2026-01-06T13:50:48Z

/retest

wlwilliamx · 2026-01-07T03:11:40Z

/retest

wlwilliamx · 2026-01-07T07:11:25Z

/retest

wk989898 · 2026-01-07T08:07:11Z

pkg/sink/mysql/helper.go


 func needWaitAsyncExecDone(t timodel.ActionType) bool {
 	switch t {
-	case timodel.ActionCreateTable, timodel.ActionCreateTables:


I think it is not a good idea to remove this. If there are lots of create table DDL, every table will query the downstream. It may affect performance. Could we handle the create table like separately?

Removing create table and create tables here is irrelevant, because only create table like will have blocked table names. Only when there are blocked table names will the query add index and wait.

wlwilliamx · 2026-01-07T10:13:12Z

/test pull-cdc-mysql-integration-light

wlwilliamx · 2026-01-07T10:13:33Z

/test pull-cdc-mysql-integration-heavy

logservice/schemastore/persist_storage_ddl_handlers.go

ti-chi-bot · 2026-01-07T10:23:12Z

[LGTM Timeline notifier]

Timeline:

2026-01-07 10:23:12.125340515 +0000 UTC m=+784147.943648957: ☑️ agreed by wk989898.

ti-chi-bot · 2026-01-07T10:23:12Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: wk989898

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wlwilliamx added 3 commits December 31, 2025 16:34

fix(ddl): fix create table like ddl don't wait add index

9578eda

refactor ut

0e7dfa5

modify error handle

24b93c6

ti-chi-bot bot added the release-note Denotes a PR that will be considered when it comes time to generate release notes. label Dec 31, 2025

wlwilliamx requested a review from lidezhu December 31, 2025 09:55

ti-chi-bot bot added the size/L Denotes a PR that changes 100-499 lines, ignoring generated files. label Dec 31, 2025

wlwilliamx changed the title ~~Fix/create table like dont wait add index~~ fix(ddl): wait running add index before CREATE TABLE LIKE Dec 31, 2025

gemini-code-assist bot reviewed Dec 31, 2025

View reviewed changes

logservice/schemastore/persist_storage_ddl_handlers.go Show resolved Hide resolved

refactor

318ea9b

set BlockedTables for create table like ddl

fd91573

ti-chi-bot bot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Jan 4, 2026

make check

faec49d

fix extract refer table info

188aa33

fix test query

9522880

wk989898 reviewed Jan 7, 2026

View reviewed changes

remove the useless func needWaitAsyncExecDone

271efc6

wk989898 approved these changes Jan 7, 2026

View reviewed changes

logservice/schemastore/persist_storage_ddl_handlers.go Outdated Show resolved Hide resolved

ti-chi-bot bot added the needs-1-more-lgtm Indicates a PR needs 1 more LGTM. label Jan 7, 2026

ti-chi-bot bot added the approved label Jan 7, 2026

modify search name with case sensitive

2a1d113

fix(ddl): wait running add index before CREATE TABLE LIKE #3863

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wlwilliamx commented Dec 31, 2025 •

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