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https://issues.apache.org/jira/browse/IGNITE-8020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16409522#comment-16409522
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Ilya Lantukh commented on IGNITE-8020:
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This ticket is still a draft. Everybody is welcome to suggest ideas or pay
attention on potential problems.
> Rebalancing for persistent caches should transfer file store over network
> instead of using existing supply/demand protocol
> --------------------------------------------------------------------------------------------------------------------------
>
> Key: IGNITE-8020
> URL: https://issues.apache.org/jira/browse/IGNITE-8020
> Project: Ignite
> Issue Type: Improvement
> Components: persistence
> Reporter: Ilya Lantukh
> Assignee: Ilya Lantukh
> Priority: Major
>
> Existing rebalancing protocol is suitable for in-memory data storage, but for
> data persisted in files it is sub-optimal and requires a lot of unnecessary
> steps. Efforts to optimize it led to necessity to completely rework the
> protocol - instead of sending batches (SupplyMessages) with cache entries it
> is possible to send data files directly.
> The algorithm should look like this:
> 1. Demander node sends requests with required partition IDs (like now)
> 2. Supplier node receives request and performs a checkpoint.
> 3. After checkpoint is done, supplier sends files with demanded partitions
> using low-level NIO API.
> 4. During steps 2-3, demander node should work in special mode - it should
> temporary store all incoming updates in such way that they can be quickly
> applied later.
> 5. After files are transferred, demander applies updates stored at step 4.
> The tricky part here is to switch work modes of demander node avoiding all
> possible race conditions. Also, the aforementioned algorithm should be
> extended to transfer or rebuild query indexes.
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