Aleksey, hello. > Hi, Sergei, > > Thank you for observations! This task is in progress. While doing it I found > out that RBR doesn't replicate timestamp fractions. > That is: it gets seconds from event timestamp marker and adds fractions from > system time. This causes bugs in System Versioning. > More on it in Bug 6 here: > https://github.com/tempesta-tech/mariadb/issues/578#issuecomment-470533050 > > I propose to fix it by adding timestamp fractions field to Log_event header > after FLAGS_OFFSET. To support backwards > compatibility it is needed to increment fdle->binlog_version and probably add > new flag LOG_EVENT_HAS_SEC_PART_F (for support > sending Log_event without fractions). Do you agree?
Adding a new flag to Log_event could indeed force the binlog_version increment. However as you're concerned with Rows_log_event the new field could be added to this class and its header. You can find how to do that in Rows_log_event::Rows_log_event. Hope this is helpful. Andrei > > On Thu, Jan 31, 2019 at 1:10 PM Sergei Golubchik <s...@mariadb.com> wrote: > > Hi, Aleksey! > > On Jan 31, Aleksey Midenkov wrote: > > revision-id: 14c2f90ad08 (versioning-1.0.7-1-g14c2f90ad08) > > parent(s): a8efe7ab1f2 > > author: Aleksey Midenkov <mide...@gmail.com> > > committer: Aleksey Midenkov <mide...@gmail.com> > > timestamp: 2018-11-17 16:30:10 +0300 > > message: > > > > Idempotent INSERT events for system versioning > > > > Case 1: Rows_log_event::write_row() always overwrite historical row. > > > > Related to MDEV-16370. > > I realized that the whole RBR logging of system versioned tables is > wrong. > > For an update you log update_row event and write_row event separately > and execute them separately. It allows trivially to manipulate the > history. > See a test case attached. > > To fix this, the slave should ignore all events that modify the history. > And generate them locally. Say, an update on the master generates > update_row and write_row events. The slave executes update_row event > which updates a current row and this also should generate the historical > row. Then the slave ignores write_row event. > > Of course, as an optimization, the master should not generate historical > write_row events, but as my test case shows, they can be forged, so the > slave should ignore them anyway, if they happen to come. > > I've created a new https://jira.mariadb.org/browse/MDEV-18432 for that, > let's not have it tied to MDEV-16370. > > Regards, > Sergei > Chief Architect MariaDB > and secur...@mariadb.org > > -- > All the best, > > Aleksey Midenkov > @midenok > > _______________________________________________ > Mailing list: https://launchpad.net/~maria-developers > Post to : maria-developers@lists.launchpad.net > Unsubscribe : https://launchpad.net/~maria-developers > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
