[
https://issues.apache.org/jira/browse/IGNITE-20187?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17762060#comment-17762060
]
Aleksandr Polovtcev commented on IGNITE-20187:
----------------------------------------------
Unfortunately, I wasn't able to write a test for this improvement, it requires
a lot of time due to my poor knowledge of Distribution Zones and rebalance
algorithm overall. Since I've already spent a lot of time on this, I've created
a separate ticket for that: IGNITE-20344
> Catch-up rebalance on node restart: assignments keys
> ----------------------------------------------------
>
> Key: IGNITE-20187
> URL: https://issues.apache.org/jira/browse/IGNITE-20187
> Project: Ignite
> Issue Type: Improvement
> Reporter: Alexander Lapin
> Assignee: Aleksandr Polovtcev
> Priority: Major
> Labels: ignite-3
> Time Spent: 10m
> Remaining Estimate: 0h
>
> h3. Motivation
> Prior to the implementation of the meta storage compaction and the related
> node restart updates, the node restored its volatile state in terms of
> assignments through ms.watches starting from APPLIED_REVISION + 1. Meaning
> that after the restart, the node was notified about missing state through
> {*}the events{*}. However, it's no longer true: new logic assumes that the
> node will register ms.watch starting from APPLIED_REVISION + X + 1 and will
> manually read local meta storage state for APPLIED_REVISION +X along with
> related processing. The implementation of the above process is the essence of
> this ticket.
> h3. Definition of Done
> Within node restart process, TableManager or similar should manually read
> local assignments pending keys (reading assignments stable will be covered in
> a separate ticket) and schedule corresponding rebalance.
> h3. Implementation Notes
> It's possible that assignemnts.pending keys will be stale at the moment of
> processing, so in order to overcome given issue following
> common-for-current-rebalance steps are proposed:
> # Start all new needed nodes {{partition.assignments.pending /
> partition.assignments.stable}}
> # After successful starts - check if current node is the leader of raft
> group (leader response must be updated by current term), if it is
> # Read distributed \{{partition.assignments.pending}} and if the retrieved
> revision is less or equal to the one retrieved within initial local read run
> RaftGroupService#changePeersAsync(leaderTerm, peers)
> RaftGroupService#changePeersAsync from old terms must be skipped.
> Seems that
> [https://github.com/apache/ignite-3/blob/main/modules/table/tech-notes/rebalance.md]
> should be also updated a bit.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
