kafka connect: coordinator only commits offsets when greater than existing offsets - #17552
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twthorn wants to merge 1 commit into
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kafka connect: coordinator only commits offsets when greater than existing offsets#17552twthorn wants to merge 1 commit into
twthorn wants to merge 1 commit into
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…sting offsets Signed-off-by: Thomas Thornton <thomaswilliamthornton@gmail.com>
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@laskoviymishka think you could take a look when you get a free moment? Thanks! |
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Fixes #17551
More context in that ticket on the exact sequence of events.
Overall, it's possible multiple coordinators exist, and one may commit old/stale offsets still in memory, which may be out of retention, and this sequence will cause data loss.
We do a check before writing the offset.
Note: it is possible that a race condition exists (eg coordinator A reads offset n, coordinator B reads offset n & commits offset n+2, and then coordinator A commits offset n+1). However, the committed offset still never drops below n, so the worst case is reprocessing a few records (ie duplicates), not data loss.
Also add some logging that makes these scenarios much more clear (eg when a stale coordinator may exist, what the coordinators offsets are that they are committing).