ddl: Non clustered reorg duplicate tidb rowid fix

[mjonss]

What problem does this PR solve?

Issue Number: close #59680

Problem Summary:
Issue is that for non-clustered, partitioned tables and REORGANIZE PARTITION (and related alters).
And possibility of EXCHANGE PARTITION, which allows duplicate _tidb_rowid's between partitions.
And the new reorganized set of partitions are not kept in-sync with the old non-reorganized partitions.

What changed and how does it work?

Original issue was #53385. After trying both "Always generate a new _tidb_rowid", (#53770, leading to #57510) and "using AddRecord", to generate new _tidb_rowid's (#57114, leading to #59680) and having the indexes up-to-date (for the currently used set of partition), there will always be issues between the original set of partitions and the reorganized set of partitions, due to not being in sync / having the same _tidb_rowid.

This solution will make sure that if a row exists in both sets of partitions, it will always have the same _tidb_rowid.

It works like this:
During backfill, if a the currents row's tidb_rowid already exists in the new partition:
If same row (content is same as current row)

• Skip backfilling it (since already there)
  else
• generate a new table unique _tidb_rowid and delete the current row and add it back with the new _tidb_rowid and save the same row, with the new _tidb_rowid in the new partition.

During DML:
Delete: Only delete the reorganized row if it matches both _tidb_rowid AND row content
Update: Use DELETE+INSERT (RemoveRecord+AddRecord) where DELETE is the same as above. When insert/AddRecord creates a new _tidb_rowid, use that newly generated id for both new and old partitions.
And INSERT: if moving between partitions in the current set of partition, then a new unique _tidb_rowid will be generated, so use that the other set of partitions as well. Else if the _tidb_rowid already exists in the other set of partitions, then generate a new _tidb_rowid and use for both sets of partitions.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

Fixed issues with concurrent DML during REORGANIZE PARTITION for non-clustered tables that had been EXCHANGED.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Defined2014, tangenta

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-03-27 02:18:32.26101975 +0000 UTC m=+1099605.945255841: ☑️ agreed by Defined2014.
• 2025-04-10 04:15:54.339742775 +0000 UTC m=+2316248.023978870: ☑️ agreed by tangenta.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.5: #60565.
But this PR has conflicts, please resolve them!

[bb7133]

/cherry-pick release-8.5

[ti-chi-bot]

@bb7133: new pull request could not be created: failed to create pull request against pingcap/tidb#release-8.5 from head ti-chi-bot:cherry-pick-60132-to-release-8.5: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","code":"custom","message":"A pull request already exists for ti-chi-bot:cherry-pick-60132-to-release-8.5."}],"documentation_url":"https://docs.github.com/rest/pulls/pulls#create-a-pull-request","status":"422"}

In response to this:

/cherry-pick release-8.5

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