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https://issues.apache.org/jira/browse/IGNITE-24817?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Denis Chudov updated IGNITE-24817:
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Epic Link: IGNITE-24900
> Transactional guarantees become unreliable in multi-zone transactions
> including in-memory zones
> -----------------------------------------------------------------------------------------------
>
> Key: IGNITE-24817
> URL: https://issues.apache.org/jira/browse/IGNITE-24817
> Project: Ignite
> Issue Type: Bug
> Reporter: Denis Chudov
> Priority: Major
> Labels: ignite-3
>
> In in-memory groups, we have persistent transaction state storage in order to
> keep the transaction state until we are sure that all write-intents are
> switched even in the case of group restart. However, the log still is
> in-memory, so if the log is not flushed and the commit partition group
> restarts or loses majority after transaction finish, and we were not able to
> switch write intents, we will lose data consistency.
> Consider the case:
> * transaction tx0 is started and two partitions are enlisted: 1_part_0
> (in-memory zone) and 2_part_0 (another zone). 1_part_0 is a commit partition.
> * tx0 is committed. Right after that, commit partition group is restarted.
> Transaction state is lost.
> * We were not able to finish the cleanup phase of tx0, but for the user, it
> is committed (because the state was written into commit partition group
> before the restart).
> * coordinator of tx0 also leaves the cluster.
> * There is a write intent in 2_part_0, but we don't know the transaction
> state. According to the regular transaction recovery procedure, we will
> rollback this transaction.
> As a result, tx0 is committed but the changes that it had done in 2_part_0
> are lost.
> In the same time, the raft log is single for each in-memory group, so tx
> state storage and partition storage share the same log and we can't make a
> persistent log for tx state storage.
> Also, the problem exists no matter which type of zone is the zone of second
> partition: in-memory or persistent.
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