Comment 13 for bug 1700593

commit 481c6e517ecba6acdfd2adc323921dc1434d2d74
Merge: 09dbf65 66b8ade
Author: Krunal Bauskar <email address hidden>
Date: Wed Oct 25 11:37:20 2017 +0530

    Merge pull request #559 from kbauskar/5.6-pxc-883

    - PXC#883: ROLLBACK to SAVEPOINT does not rollback correctly on slaves

commit 66b8ade02a2fcfa3c107e30355b2e8349287fcf9
Author: Krunal Bauskar <email address hidden>
Date: Tue Oct 24 11:24:17 2017 +0530

    - PXC#883: ROLLBACK to SAVEPOINT does not rollback correctly on slaves

      * ROLLBACK to savepoint involves 2 main actions:
        - truncate binlog to the said position
        - rollback at innodb storage engine level.

        wsrep plugin has no role to play in savepoint rollback and
        call to wsrep plugin should be avoided in such case.

      * What would happen if we call wsrep plugin rollback action
        for savepoint rollback ?
        * wsrep plugin doesn't differentiate between normal and savepoint
          rollback and so will cause complete transaction rollback there-by
          discarding valid action even befor the savepoint.
        * this drawback currently is limited to log-bin=0 but ideal solution
          is to avoid calling wsrep plugin for savepoint rollback as it doesn't
          have role to play.