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https://issues.apache.org/jira/browse/IGNITE-15222?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17451795#comment-17451795
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Mirza Aliev commented on IGNITE-15222:
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Hello, PR is ready for reviewing.
> Add test for Metastorage's cursor commands next and hasNext correctly working
> after Raft leader was changing.
> -------------------------------------------------------------------------------------------------------------
>
> Key: IGNITE-15222
> URL: https://issues.apache.org/jira/browse/IGNITE-15222
> Project: Ignite
> Issue Type: Bug
> Reporter: Mirza Aliev
> Assignee: Mirza Aliev
> Priority: Major
> Labels: ignite-3
>
> Metastorage's cursor commands next and hasNext are implemented using
> {{CursorNextCommand}} and {{CursorHasNextCommand}} Raft commands, which are
> Raft's Read Commands. Read commands are handled on Raft leader and don't
> replicate to followers. Within the context of cursors, it means that cursor
> position, which is moved by the next command, is stored on leader only and
> might be lost on leader change. It will lead to unexpected side effects on
> the raft client because from the client's point of view, the leader migration
> is seamless and should be invisible. In other words, calling next on leader A
> will only move cursor position on this particular raft node, so that after
> leader migration, the client's next {{next()}} command will be processed on a
> new leader B and will move cursor position again to the same step.
> A possible solution is to change {{CursorNextCommand}} and
> {{CursorHasNextCommand}} to raft's write commands, so they will be replicated
> on the followers and new followers will handle the commands correctly.
> UPD:
> {{CursorNextCommand}} and {{CursorHasNextCommand}} are already raft's write
> commands, so this task contains only test
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