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@bobhan1 bobhan1 commented Jan 13, 2025

pick #46841

…it txn in MS (apache#46841)

Related PR: apache#46039

Problem Summary:

apache#46039 add a defensive check when
commit_txn in MS to check whether the `lock_id` of pending delete
bitmaps on tablets involved in the txn is the current txn's `lock_id`.
But this may report a false negative in the following circumstance:

1. heavy schema change begins and add shadow index to table.
2. txn A load data to base index and shadow index.
3. txn A write its pending delete bitmaps on MS. This includes tablets
of base index and shadow index.
4. txn A failed to remove its pending delete bitmaps for some reson(e.g.
`commit_txn()` failed due to too large value)
5. txn B load data to base index and shadow index.
6. schema change failed for some reason and **remove shadow index on
table.**
7. txn B send delete bitmap calculation task to BE. **Note that this
will not involved tablets under shadow index because these tablets have
been dropped.** **So these tablets' pending delete bitmaps will still be
txn A's**.
8. txn B commit txn on MS and find that pending delete bitmaps'
`lock_id` on tablets under shadow index not match. And txn B will
failed.

We can see that the checks on these dropped tablets are useless so we
remove the mandatory check to avoid this false negative and print a
warning log instead to help locate problems.
@hello-stephen
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Thank you for your contribution to Apache Doris.
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Please clearly describe your PR:

  1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
  2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
  3. What features were added. Why was this function added?
  4. Which code was refactored and why was this part of the code refactored?
  5. Which functions were optimized and what is the difference before and after the optimization?

@bobhan1
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bobhan1 commented Jan 13, 2025

run buildall

@dataroaring dataroaring merged commit 4d68a17 into apache:branch-3.0 Jan 13, 2025
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3 participants