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https://issues.apache.org/jira/browse/FLINK-2329?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14618751#comment-14618751
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ASF GitHub Bot commented on FLINK-2329:
---------------------------------------
GitHub user tillrohrmann opened a pull request:
https://github.com/apache/flink/pull/893
[FLINK-2329] [runtime] Introduces InstanceGateway for RPCs from Executions
This PR replaces the direct `ActorRef` interaction from within `Executions`
with an `InstanceGateway`. The `InstanceGateway` is an abstraction which
encapsulates the RPC logic. This allows to more easily separate the `Execution`
logic from the used Akka framework.
The default implementation `AkkaInstanceGateway` simply forwards the
messages to the provided `ActorRef` which represents the remote instance.
The `InstanceGateway` will allow us to add leader session IDs to all
messages, which are sent to a `TaskManager`, transparently, without having to
pass this information through the `ExecutionGraph` to the `Executions`.
The additional abstraction layer allows to write more light-weight tests,
too. As a consequence, many test cases which needed an `ActorSystem` to start a
simple testing actor which mimicked the remote end, could now be simplified
using a simple `InstanceGateway` implementation and thus getting rid off
testing `ActorSystems`.
In the wake of refactoring, I also replaced the
`AkkaUtils.globalExecutionContext` with a non global one. At the moment, the
`JobManager` and the `TaskManager` both start a single `ForkJoinPool` which is
used as the `ExecutionContext` for all futures and future handlers. The default
parallelism is the number of cores available on the system. It would now also
be possible to use even more fine grained `ExecutionContexts`, e.g. giving each
`ExecutionGraph` a distinct `ExecutionContext`.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/tillrohrmann/flink leaderSessionID
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/893.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #893
----
commit 43e15aa73dde20166cd9973cd5418fe352ea02d4
Author: Till Rohrmann <[email protected]>
Date: 2015-07-07T09:41:44Z
[FLINK-2329] [runtime] Introduces InstanceGateway as an abstraction to
communicate with the TaskManager. Replaces AkkaUtils.globalExecutionContext
with instance dependent ExecutionContext.
Add comments for newly introduced classes
----
> Refactor RPCs from within the ExecutionGraph
> --------------------------------------------
>
> Key: FLINK-2329
> URL: https://issues.apache.org/jira/browse/FLINK-2329
> Project: Flink
> Issue Type: Sub-task
> Components: JobManager, TaskManager
> Reporter: Till Rohrmann
> Assignee: Till Rohrmann
> Fix For: 0.10
>
>
> Currently, we store an {{ActorRef}} of the TaskManager into an {{Instance}}
> object. This {{ActorRef}} is used from within {{Executions}} to interact with
> the {{TaskManager}}. This is not a nice abstraction since it does not hide
> implementation details.
> Since we need to add a leader session ID to messages sent by the
> {{Executions}} in order to support high availability, we would need to make
> the leader session ID available to the {{Execution}}. A better solution seems
> to be to replace the direct {{ActorRef}} interaction with an instance gateway
> abstraction which encapsulates the communication logic. Having such an
> abstraction, it will be easy to decorate messages transparently with a leader
> session ID. Therefore, I propose to refactor the current {{Instance}}
> communication and to introduce an {{InstanceGateway}} abstraction.
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