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Internal dispatcher to protect against starvation (#26816)

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* Allow for dispatcher aliases and define a internal dispatcher
* Test checking dispatcher name
* MiMa for Dispatchers
* Migration guide entry
* No need to have custom dispatcher lookup logic in streams anymore
* Default dispatcher size and migration note about that
* Test checking exact config values...
* Typed receptionist on internal dispatcher
* All internal usages of system.dispatcher gone through
This commit is contained in:
Johan Andrén 2019-05-02 22:35:25 +02:00 • committed by Patrik Nordwall
parent e34a711adf
commit 81b1e2ef9b
57 changed files with 524 additions and 329 deletions
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35
akka-docs/src/main/paradox/cluster-usage.md
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@ -877,37 +877,10 @@ akka.cluster.log-info-verbose = on
<a id="cluster-dispatcher"></a>
### Cluster Dispatcher
Under the hood the cluster extension is implemented with actors and it can be necessary
to create a bulkhead for those actors to avoid disturbance from other actors. Especially
the heartbeating actors that is used for failure detection can generate false positives
if they are not given a chance to run at regular intervals.
For this purpose you can define a separate dispatcher to be used for the cluster actors:
```
akka.cluster.use-dispatcher = cluster-dispatcher
cluster-dispatcher {
type = "Dispatcher"
executor = "fork-join-executor"
fork-join-executor {
parallelism-min = 2
parallelism-max = 4
}
}
```
@@@ note
Normally it should not be necessary to configure a separate dispatcher for the Cluster.
The default-dispatcher should be sufficient for performing the Cluster tasks, i.e. `akka.cluster.use-dispatcher`
should not be changed. If you have Cluster related problems when using the default-dispatcher that is typically an
indication that you are running blocking or CPU intensive actors/tasks on the default-dispatcher.
Use dedicated dispatchers for such actors/tasks instead of running them on the default-dispatcher,
because that may starve system internal tasks.
Related config properties: `akka.cluster.use-dispatcher = akka.cluster.cluster-dispatcher`.
Corresponding default values: `akka.cluster.use-dispatcher =`.
@@@
Under the hood the cluster extension is implemented with actors. To protect them against
disturbance from user actors they are by default run on the internal dispatcher configured
under `akka.actor.internal-dispatcher`. The cluster actors can potentially be isolated even
further onto their own dispatcher using the setting `akka.cluster.use-dispatcher`.
### Configuration Compatibility Check