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https://issues.apache.org/jira/browse/ACCUMULO-4355?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16349130#comment-16349130
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Mark Owens commented on ACCUMULO-4355:
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Broke out the various feature requests into sub-task of this ticket.
> Provide more granular control for bulk import operations
> --------------------------------------------------------
>
> Key: ACCUMULO-4355
> URL: https://issues.apache.org/jira/browse/ACCUMULO-4355
> Project: Accumulo
> Issue Type: Wish
> Components: master, tserver
> Reporter: Shawn Walker
> Assignee: Shawn Walker
> Priority: Major
> Fix For: 2.0.0
>
>
> Accumulo currently provides mechanisms to initiate bulk imports and to list
> bulk imports in progress. Scheduling of bulk import requests is not entirely
> deterministic, and most of the execution of a bulk-import request is done in
> a non-preemptable manner. As such, any bulk import which takes very long to
> complete can block bulk imports with higher operational priority for
> significant periods.
> To better support bulk-import-heavy applications, it would be nice if
> Accumulo would offer additional mechanisms for controlling the scheduling and
> execution of bulk imports, such as the abilities to:
> * Pause/resume bulk import in progress.
> * Prioritize/reprioritize bulk import requests.
> * Cancel bulk import in progress. If possible, cancelling a partially
> completed bulk import request should result in a rollback of changes. That
> is, a bulk import should either succeed or make no changes.
> Additionally, for multitenant situations, it would be nice if Accumulo would:
> * Provide multiple queues for bulk import requests. Each queue would have
> its requests worked serially in priority order. Requests in separate queues
> should be worked in parallel, or have time distributed among the queues in
> some manner as to make work appear roughly parallel.
> ----
> Implementation-wise, I'm thinking of rewriting much of the current
> bulk-loading logic. While the current logic depends upon multiple threads
> executing (potentially long-duration) blocking RPC calls, I'd like to move to
> a more event-driven/message-passing model backed by a persistent state
> machine.
> Current ideas I'm playing around with (very tentative)
> * Creating a new table {{accumulo.bulk_load_queues}} to keep track of bulk
> load progress.
> * Distributing bulk load orchestration via a mechanism similar to tablet
> assignment instead of the current blocking RPC calls (LoadFiles.java:156).
> * Implementing something akin to a two-phase commit to achieve rollback
> behavior on failure.
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