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https://issues.apache.org/jira/browse/IGNITE-22819?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexander Lapin reassigned IGNITE-22819:
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Assignee: Alexander Lapin
> Metastorage revisions inconsistency
> -----------------------------------
>
> Key: IGNITE-22819
> URL: https://issues.apache.org/jira/browse/IGNITE-22819
> Project: Ignite
> Issue Type: Bug
> Reporter: Ivan Bessonov
> Assignee: Alexander Lapin
> Priority: Major
> Labels: ignite-3
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Following situation might happen:
> {code:java}
> [2024-07-24T09:29:17,220][INFO
> ][%itcskvt_n_0%JRaft-FSMCaller-Disruptormetastorage_stripe_0-0][MetaStorageWriteHandler]
> Idempotent command cache cleanup finished [cleanupTimestamp=HybridTimestamp
> [physical=2024-07-24 09:29:17:220 +0300, logical=0,
> composite=112840052389969920], cleanupCompletionTimestamp=HybridTimestamp
> [physical=2024-07-24 09:29:17:220 +0300, logical=1,
> composite=112840052389969921], removedEntriesCount=0, cacheSize=240].
> ...
> [2024-07-24T09:29:17,257][INFO
> ][%itcskvt_n_2%JRaft-FSMCaller-Disruptormetastorage_stripe_0-0][MetaStorageWriteHandler]
> Idempotent command cache cleanup finished [cleanupTimestamp=HybridTimestamp
> [physical=2024-07-24 09:29:17:257 +0300, logical=0,
> composite=112840052392394752], cleanupCompletionTimestamp=HybridTimestamp
> [physical=2024-07-24 09:29:17:257 +0300, logical=1,
> composite=112840052392394753], removedEntriesCount=3, cacheSize=237].
> [2024-07-24T09:29:17,257][INFO
> ][%itcskvt_n_1%JRaft-FSMCaller-Disruptormetastorage_stripe_0-0][MetaStorageWriteHandler]
> Idempotent command cache cleanup finished [cleanupTimestamp=HybridTimestamp
> [physical=2024-07-24 09:29:17:257 +0300, logical=0,
> composite=112840052392394752], cleanupCompletionTimestamp=HybridTimestamp
> [physical=2024-07-24 09:29:17:257 +0300, logical=1,
> composite=112840052392394753], removedEntriesCount=3, cacheSize=237].{code}
> Note that {{removedEntriesCount}} is 0 on a leader and 3 on followers,
> because of the difference of their clocks. {{evictIdempotentCommandsCache}}
> works differently on different nodes for the same raft commands.
> The real problem here is that it might (or might not) call the
> {{{}storage.removeAll(commandIdStorageKeys, safeTime){}}}, which would
> increase local revision.
>
> Revision is always local, it's never replicated. Revision mismatch leads to
> different evaluation of conditions in conditional updates and invokes. Simple
> example of such an issue would be a skipped configuration update on one or
> several nodes in cluster.
>
> What can we do about it:
> * make an alternative for {{removeAll}} that doesn't increase local revision
> * call {{removeAll}} even if the list is empty
> * never invalidate cache locally, but rather replicate cache invalidation
> with a special command
> * there's a TODO that says "clear this during compaction". That's a bad
> option, it would lead to either frequent compactions, or huge memory overheads
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