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  1. Percona Server
  2. PS-4153

Alter gap lock error logic to account for ISO mode

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    Details

    • Type: Admin & Maintenance Task
    • Status: Done
    • Priority: Medium
    • Resolution: Done
    • Affects Version/s: None
    • Fix Version/s: 5.7.18-14
    • Component/s: MyRocks
    • Labels:

      Description

      Our gap lock error implementation (from MYR-15) currently is not taking into account the current ISO mode. This logic should be changed to amend an additional condition before deciding to error to the client:

      && thd_tx_isolation(thd) >= ISO_REPEATABLE_READ
      

      Therefore, if the ISO is <= READ COMMITTED, the gap lock error will not be raised in the condition of a gap lock, but as the ISO mode moves any further north in the consistency scale to REPEATABLE READ or SERIALIZABLE, then the gap lock error will be raised when conditions are met.

      We will need to clearly document this behavior and the suggested default ISO mode of READ COMMITTED with MyRocks use cases. We will also need to update the MyRocks mtr suites to explicitly test ISO modes against the gap lock error, change the default ISO mode for the suites to READ COMMITTED, and re-word the error message.

      https://bugs.launchpad.net/percona-server/+bug/1658843

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              • Assignee:
                george.lorch George Lorch
                Reporter:
                george.lorch George Lorch
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