initial, simple solution to our-of-order applying of DML events #31
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- Operation would terminate after events lock noticed but before applying all events: race condition where the event would be captured asynchronously. The event is now handled sequentially with the DML events, hence now safe. - Multiple rowcopy operations would still write to `rowCopyComplete` channel. This is still the case, but now we only wait for the first and then just flush (read and discard) any others, to avoid blocking - Events DML listener is only added after table creation: the problem was that with very busy tables, the events func buffer would fill up, and the "tables-created" event would be blocked. - `waitForEventsUpToLock()` unifies the waiting on all variants of complete-migration - With `--test-on-replica`, now stopping replication "nicely", using `master_pos_wait()` - With `--test-on-replica`, not throttling on replication after replication is stopped (duh) - More debug output
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Solved various race conditions:
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timvaillancourt
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Aug 4, 2022
Support zero date and zero in date, via dedicated command line flag
timvaillancourt
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Support zero date and zero in date, via dedicated command line flag
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Support zero date and zero in date, via dedicated command line flag
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Aug 10, 2022
* Merge pull request #31 from openark/zero-date Support zero date and zero in date, via dedicated command line flag * Merge pull request #32 from openark/existing-date-with-zero Support tables with existing zero dates * Remove un-needed ignore_versions file * Fix new lint errors from golang-ci update Co-authored-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
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Storyline: #30
This is the first and potentially last change so as to solve the out-of-order issue.
The change is to not have the DML event func run asynchronously. They were originally introduced to run synchronously when the heartbeat mechanism was using binlog events as well. That turned out to be a wrong implementation, and heartbeat now uses plain old table queries.
There is a buffer of
100event entries that will allow for a queue buildup of DML events. See https://github.com/github/gh-osc/blob/master/go/logic/migrator.go#L34 and https://github.com/github/gh-osc/blob/master/go/logic/migrator.go#L69So up to
100unhandled events can still build up without further blocking DML events such asstatusentries. I'm not at all sure at this point we should care about the DML events blocking other events. Running with this small change.