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https://issues.apache.org/jira/browse/IGNITE-9314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16771100#comment-16771100
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Ivan Pavlukhin commented on IGNITE-9314:
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After a discussion with [~gvvinblade], [~amashenkov], [~agoncharuk],
[~ivan.glukos] it was found that streaming via primary node can lead to
unhandled data inconsistency between partition replicas, so this approach
cannot guarantee data consistency in failover scenarios.
It also known that current implementation of `IgniteDataStreamer` has multiple
problems which can lead to inconsistent data. The most promising approach is
streaming to exclusively locked table. In that case inserts can be done using
special _initial version_ and incrementing counters one by one at a time of
insert.
Other approaches can be studied. Among them is using special
_write-conflict-free_ semantics for streamer updates. But any other approach
should be thoroughly evaluated.
> MVCC TX: Datastreamer operations
> --------------------------------
>
> Key: IGNITE-9314
> URL: https://issues.apache.org/jira/browse/IGNITE-9314
> Project: Ignite
> Issue Type: Task
> Components: mvcc
> Reporter: Igor Seliverstov
> Assignee: Ivan Pavlukhin
> Priority: Major
> Fix For: 2.8
>
>
> Need to change DataStreamer semantics (make it transactional)
> Currently clients can see DataStreamer partial writes and two subsequent
> selects, which are run in scope of one transaction at load time, may return
> different results.
> Related thread:
>
> [http://apache-ignite-developers.2346864.n4.nabble.com/MVCC-and-IgniteDataStreamer-td32340.html]
> Also there is a problem when {{DataStreamer}} with {{allowOverwrite ==
> false}} does not insert value when versions for entry exist but they all are
> aborted. Proper transactional semantics should developed for such case. After
> that attention should be put on Cache.size method behavior. Cache.size
> addressed in https://issues.apache.org/jira/browse/IGNITE-8149 could be
> decremented improperly in
> {{org.apache.ignite.internal.processors.cache.IgniteCacheOffheapManager#mvccRemoveAll}}
> method (called during streamer processing) when all existing mvcc row
> versions are aborted or last committed one is _remove_ version.
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