fix(shard-distributor): send initial state to new subscribers#7499
Merged
jakobht merged 8 commits intocadence-workflow:masterfrom Dec 2, 2025
Merged
fix(shard-distributor): send initial state to new subscribers#7499jakobht merged 8 commits intocadence-workflow:masterfrom
jakobht merged 8 commits intocadence-workflow:masterfrom
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Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
jakobht
requested review from
3vilhamster,
Shaddoll,
davidporter-id-au,
demirkayaender,
dkrotx,
neil-xie,
sankari165,
shijiesheng and
taylanisikdemir
as code owners
jakobht
changed the title
Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
eleonoradgr
reviewed
Dec 1, 2025
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| // The go routine sends the initial state to the subscriber. | ||
| go func() { | ||
| n.RLock() |
Contributor
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we are already locking and inside the function we can remove this
eleonoradgr
reviewed
Dec 1, 2025
| func (n *namespaceShardToExecutor) Subscribe(ctx context.Context) (<-chan map[*store.ShardOwner][]string, func()) { | ||
| return n.pubSub.subscribe(ctx) | ||
| subCh, unSub := n.pubSub.subscribe(ctx) | ||
| n.logger.Info("initial state", tag.ShardNamespace(n.namespace), tag.Value(n.getExecutorState())) |
Contributor
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I would suggest to move this in the go routine and use the same state that we are going to send instead of querying the method twice
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I think we don't need this log at all, deleted it
Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
eleonoradgr
approved these changes
Dec 1, 2025
Signed-off-by: Jakob Haahr Taankvist <jht@uber.com>
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What changed?
Modified the
Subscribemethod innamespaceShardToExecutorto send the initial executor state to new subscribers immediately upon subscription, and refactoredgetExecutorStateinto a separate method to safely retrieve a copy of the current state.Removed logic for sending initial state from the handler. The logic didn't send the metadata for the executors.
Improved test infrastructure by updating
setupExecutorWithShardsto use atomic etcd transactions and to properly delete old testdata.Why?
New subscribers were not receiving the initial state when they subscribed to the executor state pub/sub, causing them to wait for the next update before getting data. This lead to delays in subscribers getting the current shard distribution.
The test improvements ensure executor setup happens atomically and makes tests more maintainable by ensuring deletion of stale state.
How did you test it?
Unit tests
Potential risks
Release notes
Documentation Changes