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https://issues.apache.org/jira/browse/IGNITE-4477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16026104#comment-16026104
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Vladimir Ozerov commented on IGNITE-4477:
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[~dkarachentsev], my comments:
1) {{IgniteFuture}} - invalid JavaDocs. You claim that {{null}} executor will
move callback to the public pool, while in reality you throw an exception. I
think it is correct to disallow {{null}} here, so only JavaDocs need to be
fixed;
2) {{IgniteFutureImpl.chainInternal}} - why did you change the whole
implementation? There is already proper method to pass executor to in internal
future: {{GridFutureAdapter.chain(IgniteClosure, Executor)}}
> Fix IgniteFuture.listen() and IgniteFuture.chain() semantics
> ------------------------------------------------------------
>
> Key: IGNITE-4477
> URL: https://issues.apache.org/jira/browse/IGNITE-4477
> Project: Ignite
> Issue Type: Task
> Components: general
> Affects Versions: 1.8
> Reporter: Vladimir Ozerov
> Assignee: Dmitry Karachentsev
> Labels: important
> Fix For: 2.1
>
>
> *Problem*
> We allow users to pass continuations to {{IgniteFuture}} which will be
> executed on future completion. This can be done through {{listen}} or
> {{chain}} methods.
> However, continuation semantics is broken intrinsically:
> 1) If future is already completed, user code executed in the same thread;
> 2) If future is not completed yet, it will be executed in completion thread.
> Neither of this options are valid because it easily leads to starvation. E.g.:
> {code}
> IgniteFuture fut = cache.getAsync(key2);
> fut.listen(fut0 -> {
> cache.put(key2, val2); // Possible deadlock, because invoked in sys pool;
> });
> {code}
> *Solution*
> 1) By default callbacks must be executed asynchronously in some common pool
> (public pool? new "callback pool"? FJP?)
> 2) It should be possible to specify where to execute a callback explicitly:
> {code}
> IgniteFuture.listen(IgniteClosure, ExecutorService);
> {code}
> 3) We may want to expose our public pool on API for convenience.
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