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https://issues.apache.org/jira/browse/IMPALA-9930?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17243626#comment-17243626
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ASF subversion and git services commented on IMPALA-9930:
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Commit ca884476bb9f3ed2de3927a8c7d8107f8551f8f8 in impala's branch
refs/heads/master from Thomas Tauber-Marshall
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=ca88447 ]
IMPALA-9930 (part 2): Introduce new admission control rpc service
This patch introduces a new krpc service, AdmissionControlService,
which coordinators can use to submit queries for admission.
This patch adds some simple configuration flags that make it possible
to have coordinators use this service to submit their queries for
admission to other coordinators. These flags are only to make this
patch testable and will be replaced when the separate admission
control daemon is introduced in IMPALA-9975.
The interface consists of the following RPCs:
- AdmitQuery: takes a TQueryExecRequest and a TQueryOptions
(serialized into sidecars), places the request on a queue to be
processed by a thread pool and then immediately returns.
- GetQueryStatus: takes a query id and returns the current admission
status, including the QuerySchedulePB if admission has completed
successfully but the query has not been released yet.
- ReleaseQueryBackends: called when individual backends complete but
the overall query is still running to release resources
incrementally. This RPC will be called at most O(log(# backends))
per query due to BackendResourceState, which batches backends to
release together.
- ReleaseQuery: called when the query has completely finished.
Releases all remaining resources.
- CancelAdmission: called if a query is cancelled before an admission
decision has been made to indicate that it should no longer be
considered for admission.
The majority of the patch consists of two classes:
- AdmissionControlClient: used to abstract whether admission is being
performed locally or remotely. In the local case, it is basically
just a wrapper around AdmissionController. In the remote case, it
handles serializing/deserializing of RPC params, polling
GetQueryStatus() until a decision has been made, etc.
- AdmissionControlService: exports the RPC interface and acts as a
wrapper around AdmissionController.
Some notable changes involved:
- AdmissionController::SubmitForAdmission() no longer blocks while a
query is queued. Instead, a new function WaitOnQueued() can be used
to monitor the admission status of a queued query.
- Adding events to the query timeline is moved out of
AdmissionController and into the AdmissionControlClient classes, so
that it always happens on the coordinator.
- When a cluster is run in the new admission control service mode,
only the impalad that is performing admission control exposes the
/admission http endpoint. Observability will be cleaned up in a
subsequent patch.
Testing:
- Modified existing admission control tests to run both with and
without the admission control service enabled, including both the
functional and stress tests. The 'num_queries' param in the stress
test is modified to only use a single value to reduce the number of
tests that are run and keep the running time reasonable.
- Ran tpch10 on a local minicluster and observed no significant
regressions.
Change-Id: I594fc593a27b24b6952e381a9bc1a9a5c6b757ae
Reviewed-on: http://gerrit.cloudera.org:8080/16412
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
> Introduce new admission control rpc service
> -------------------------------------------
>
> Key: IMPALA-9930
> URL: https://issues.apache.org/jira/browse/IMPALA-9930
> Project: IMPALA
> Issue Type: Sub-task
> Components: Backend
> Affects Versions: Impala 4.0
> Reporter: Thomas Tauber-Marshall
> Assignee: Thomas Tauber-Marshall
> Priority: Major
>
> In order to support the eventual single admission controller, we'll need to
> create rpc definitions for the service.
> The rpcs that will need to be defined are outlined in the design doc:
> https://docs.google.com/document/d/1nLovzk4rwZLct2yl-eT7VMHFBP7LswcJp7RqiP59RAc/edit
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