owner: wait all task metadata cleaned before creating new changefeed (#1212) #1213
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cherry-pick #1212 to release-4.0
What problem does this PR solve?
Fix https://github.com/pingcap/ticdc/issues/1211
Root cause: There exists race condition when CDC owner creates a new changefeed (which will assign new task status) and a stale processor stops (which is responsible for replicating the same changefeed). The latest task status written by owner could be deleted by a stale processor.
What is changed and how it works?
This PR changes the update of
task status
to a linearizable way, which means a paused/removed task status can be deleted, but cannot be put.TODO: We should summary the schedule model of CDC owner and processor to make it works in a provable automaton.
Check List
Tests
Release note