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  1. MariaDB Server
  2. MDEV-14589

InnoDB should not lock a delete-marked record

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    Description

      When a transaction is able to delete-mark a record and commit the change, no active transaction may possibly have seen (and locked) the record. The record can be removed by the purge thread at any time, and it is logically equivalent to a gap (non-existing record).

      However, currently InnoDB transactions will lock committed delete-marked records.

      How to repeat:
      Run at least 3 identical DELETE statements in parallel, and possibly some INSERT with a key value slightly smaller than that of the deleted record. InnoDB should report a bogus deadlock between 2 DELETE statements:

      trx (1) has obtained an X-lock on the delete-marked committed record
      trx (2) is waiting for an X-lock on the record and the preceding gap
      trx (1) is waiting for an X-lock on the record and the preceding gap

      Suggested fix:
      Transactions should ignore committed delete-marked records when they come across them.

      The solution we will try to implement is that when using isolation level is READ COMMITTED then DELETE will ignore any delete marked rows.

      This is same as https://bugs.mysql.com/bug.php?id=19762

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-26475 InnoDB must not lock delete-marked records

          • Major - Major loss of function.
          • Open

          Bug - A problem which impairs or prevents the functions of the product. MDEV-26642 Weird SELECT view when a record is modified to the same value by two transactions

          • Critical - Crashes, loss of data, severe memory leak.
          • Confirmed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-10962 Deadlock with 3 concurrent DELETEs by unique key

          • Major - Major loss of function.
          • Stalled

          Bug - A problem which impairs or prevents the functions of the product. MDEV-16675 Unnecessary explicit lock acquisition during UPDATE or DELETE

          • Major - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-20605 Awaken transaction can miss inserted by other transaction records due to wrong persistent cursor restoration

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

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              marko Marko Mäkelä
              monty Michael Widenius
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              Dates

                Created:
                Updated:
                Resolved:

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