Hello!
Do you have some kind of reproducer which demonstrates the issue?
Regards,
--
Ilya Kasnacheev
чт, 28 янв. 2021 г. в 10:32, Zhenya Stanilovsky <arzamas...@mail.ru.invalid
>:
>
> Hello Igniters !
> In the process of Ignite usage i found that some part of Compute
> functionality are thread unsafe and seems was designed with such
> limitations initially.
> Example : one (client, but it doesn`t matter at all) instance is
> shared between numerous of fabric, all of them calls something like :
> IgniteCompute#execute(ComputeTask<T,R>, T)
> or
> IgniteCompute#execute(java.lang.Class<? extends ComputeTask<T,R>>, T)
> and appropriate «async» methods — what kind of instance will be called is
> nondeterministic for now and as a confirmation of my words — i found no
> tests covered multi thread usage of Computing i also found nothing on
> documentation page [1].
> We have all necessary info for correct processing of such cases:
> from initiator (ignite.compute(...) starter) side we have Class or it
> instance and appropriate class loader which will be wired by class loader
> id from execution side.
> I create a fix and seems all work perfectly well besides one place, this
> functionality :
> /**
> * Executes given task within the cluster group. For step-by-step
> explanation of task execution process
> * refer to {@link ComputeTask} documentation.
> * <p>
> * If task for given name has not been deployed yet, then {@code taskName}
> will be
> * used as task class name to auto-deploy the task (see {@link
> #localDeployTask(Class, ClassLoader)} method).
> */
> public <T, R> R execute(String taskName, T arg) throws IgniteException;
> and attendant
> /**
> * Finds class loader for the given class.
> *
> * @param rsrcName Class name or class alias to find class loader for.
> * @return Deployed class loader, or {@code null} if not deployed.
> */
> public DeploymentResource findResource(String rsrcName);
> is thread unsafe by default, no guarantee that concurrent call of
> localDeployTask and execute will bring expected result.
> My proposal is to deprecate (or probably annotate [2], as a minimal
> — additionally document it) this methods and to append additional :
> public DeploymentResource findResource(String rsrcName, ClassLoader
> clsLdr);
> Only one problem i can observe here, if someone creates new class loaders
> and appropriate class instances in loop (i don`t know the purpose) and
> doesn`t undeploy them then he will get possibly OOM here.
>
> Such approach will give a possibility to use compute in concurrent
> scenario. If there is no objections here i will mark this methods and
> publish my PR, of course with additional tests.
>
> What do you think ?
>
>
> [1]
> https://ignite.apache.org/docs/latest/code-deployment/peer-class-loading
> [2]
> https://jcip.net/annotations/doc/net/jcip/annotations/NotThreadSafe.html
>
>
