fixes: deadlock when swap waitForFollowersToCatchUp#788
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mattisonchao merged 12 commits intomainfrom Oct 25, 2025
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waitForFollowersToCatchUp
merlimat
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Oct 25, 2025
| "oxia": "election-fencing-failed-followers", | ||
| "shard": fmt.Sprintf("%d", s.shard), | ||
| }, func() { | ||
| s.keepFencingFailedFollowers(s.shardMetadata.Term, s.shardMetadata.Ensemble, s.shardMetadata.Leader, followers) |
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We are reading the metadata from the go-routine, outside of its mutex. We can make a clone before or acquire the mutex here
| for _, sa := range s.shardMetadata.Ensemble { | ||
| if sa == *s.shardMetadata.Leader { | ||
| group := sync.WaitGroup{} | ||
| defer group.Wait() |
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What's the reason for waiting at the end of the method, if we are not going to return any error?
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It's useless so far. Let me remove it. :)
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rely on the #790 |
merlimat
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Oct 25, 2025
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Motivation
fixes: #845
In the current implementation. The shard controller might be stuck in the
swapmethod due towaitForFollowersToCatchUp.The root cause is the swap waiting for
waitForFollowersToCatchUp, but the new follower needs to wait fornewTermAndAddFollowerOpto be fenced and added as a follower.Modification
waitForFollowersToCatchUpoperation out ofshardControllermain loop.