sink: modify the write order of the index file and data file in storage writer

[wk989898]

What problem does this PR solve?

Issue Number: close #3784

What is changed and how it works?

Index File Write Order: The process of writing the index file has been reordered to occur after the corresponding data file is successfully written, ensuring better consistency in cloud storage.
writeDataFile Signature Update: The writeDataFile function now accepts both the data file path and the index file path as distinct arguments, improving clarity and enabling the reordered write logic.

After this PR, the data file will be written before the index file. If the CDC restarts:

1. If the index file is written, the data may be duplicated to write a new data file.
2. If the index file is not written, the data file will be overwritten.

Check List

Tests

• Unit test
• Integration test

Questions

Will it cause performance regression or break compatibility?

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

Release note

 `None`.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[wk989898]

/test all

[gemini-code-assist]

Summary of Changes

Hello @wk989898, 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 refactors the cloud storage writing mechanism by changing the order in which data and index files are persisted. The primary goal is to enhance the consistency of data written to cloud storage by ensuring that the index file, which references a data file, is only created or updated after the data file itself has been successfully written. This prevents potential issues with orphaned or invalid index entries.

Highlights

• Index File Write Order: The process of writing the index file has been reordered to occur after the corresponding data file is successfully written, ensuring better consistency in cloud storage.
• writeDataFile Signature Update: The writeDataFile function now accepts both the data file path and the index file path as distinct arguments, improving clarity and enabling the reordered write logic.
• Enhanced Write Consistency: By ensuring the index file is only written after the data file, the change prevents scenarios where an index might point to a non-existent or incomplete data file in cloud storage.

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[gemini-code-assist]

Code Review

This pull request refactors the file writing logic in the cloud storage sink by changing the order of operations to write the data file before the index file. This is a good improvement for atomicity and reliability, as it prevents a state where an index file points to a non-existent data file. The change also correctly handles errors from writing the index file, which was a bug in the previous implementation. I have one suggestion to further improve error handling by cleaning up orphaned data files on failure, making the process even more robust.

[wk989898]

/test pull-cdc-storage-integration-heavy

[wk989898]

pull-cdc-storage-integration-light

[3AceShowHand]

also update the log

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 3AceShowHand, hongyunyan

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Details

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• OWNERS [3AceShowHand,hongyunyan]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-12-25 05:23:17.120086604 +0000 UTC m=+2314541.933864166: ☑️ agreed by hongyunyan.
• 2025-12-29 06:58:22.8588123 +0000 UTC m=+2665847.672589871: ☑️ agreed by 3AceShowHand.