[jira] [Commented] (IGNITE-13382) DurableBackgroundTask can abandon incomplete task

["Sergey Chugunov (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-13382?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17188491#comment-17188491 ] 

Sergey Chugunov commented on IGNITE-13382:
------------------------------------------

[~makedonskaya],

Merged to master in commit *04ae61f668b65a6f7881f090c9481cdf3ccad25c*, thank you for contribution!

> DurableBackgroundTask can abandon incomplete task
> -------------------------------------------------
>
>                 Key: IGNITE-13382
>                 URL: https://issues.apache.org/jira/browse/IGNITE-13382
>             Project: Ignite
>          Issue Type: Bug
>    Affects Versions: 2.7
>            Reporter: Maria Makedonskaya
>            Assignee: Maria Makedonskaya
>            Priority: Major
>             Fix For: 2.10
>
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> DurableBackgroundTasks are tracked using metastorage, there's a specific marker for every task, and it is removed right after the task is complete.
> But there's a race between checkpointer and metastorage. End-marker removal is a logical operation, while task itself is mostly physical (at least the existing one). So, following scenario is possible:
> * Checkpoint occurs in the middle of the task;
> * Task is completed before the next checkpoint;
> * Metastorage record is deleted, this fact if written to WAL and synced to the storage;
> * Node failed;
> * Recovery process applies deletion from metastorage, this means that DurableBackgroundTasks info is lost;
> * But part of the index is still present in the storage.
> I think that we should remove markers from metastorage only after the next checkpoint, this will 100% save us from such situation.



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