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https://issues.apache.org/jira/browse/HIVE-17481?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16438765#comment-16438765
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Prasanth Jayachandran commented on HIVE-17481:
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[~thai.bui] Can you paste the output from console by setting
hive.tez.session.events.print.summary=text ?
The latest master build should have a separate event that updates the
guaranteed task allocation. Also the tasks gets preempted only when there are
other task waiting with guaranteed allocation. In your example, queries running
in slow pool will get guaranteed 50% allocation but if the cluster is free the
same query will use the idle resources in speculative mode. Now when a new
query comes to default pool it will get its share of guaranteed allocation 50%
and will pre-empt speculative tasks from query running in slow pool.
> LLAP workload management
> ------------------------
>
> Key: HIVE-17481
> URL: https://issues.apache.org/jira/browse/HIVE-17481
> Project: Hive
> Issue Type: New Feature
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Priority: Major
> Fix For: 3.0.0
>
> Attachments: Workload management design doc.pdf
>
>
> This effort is intended to improve various aspects of cluster sharing for
> LLAP. Some of these are applicable to non-LLAP queries and may later be
> extended to all queries. Administrators will be able to specify and apply
> policies for workload management ("resource plans") that apply to the entire
> cluster, with only one resource plan being active at a time. The policies
> will be created and modified using new Hive DDL statements.
> The policies will cover:
> * Dividing the cluster into a set of (optionally, nested) query pools that
> are each allocated a fraction of the cluster, a set query parallelism,
> resource sharing policy between queries, and potentially others like
> priority, etc.
> * Mapping the incoming queries into pools based on the query user, groups,
> explicit configuration, etc.
> * Specifying rules that perform actions on queries based on counter values
> (e.g. killing or moving queries).
> One would also be able to switch policies on a live cluster without (usually)
> affecting running queries, including e.g. to change policies for daytime and
> nighttime usage patterns, and other similar scenarios. The switches would be
> safe and atomic; versioning may eventually be supported.
> Some implementation details:
> * WM will only be supported in HS2 (for obvious reasons).
> * All LLAP query AMs will run in "interactive" YARN queue and will be
> fungible between Hive pools.
> * We will use the concept of "guaranteed tasks" (also known as ducks) to
> enforce cluster allocation without a central scheduler and without
> compromising throughput. Guaranteed tasks preempt other (speculative) tasks
> and are distributed from HS2 to AMs, and from AMs to tasks, in accordance
> with percentage allocations in the policy. Each "duck" corresponds to a CPU
> resource on the cluster. The implementation will be isolated so as to allow
> different ones later.
> * In future, we may consider improved task placement and late binding,
> similar to the ones described in Sparrow paper, to work around potential
> hotspots/etc. that are not avoided with the decentralized scheme.
> * Only one HS2 will initially be supported to avoid split-brain workload
> management. We will also implement (in a tangential set of work items)
> active-passive HS2 recovery. Eventually, we intend to switch to full
> active-active HS2 configuration with shared WM and Tez session pool (unlike
> the current case with 2 separate session pools).
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