[jira] [Commented] (IGNITE-22959) Fix incorrect ThreadPoolExecutor usages

["Kirill Tkalenko (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-22959?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17956122#comment-17956122 ] 

Kirill Tkalenko commented on IGNITE-22959:
------------------------------------------

Looks good.

> Fix incorrect ThreadPoolExecutor usages 
> ----------------------------------------
>
>                 Key: IGNITE-22959
>                 URL: https://issues.apache.org/jira/browse/IGNITE-22959
>             Project: Ignite
>          Issue Type: Improvement
>            Reporter: Philipp Shergalis
>            Assignee: Philipp Shergalis
>            Priority: Major
>              Labels: ignite-3
>          Time Spent: 1h
>  Remaining Estimate: 0h
>
> ThreadPoolExecutors with unbounded queues and without allowCoreThreadTimeout actually work as fixed thread pools, ignoring maximumPoolSize and keepAlive properties. All usages of ThreadPoolExecutor constructor should be examined and fixed:
> 1) If this behaviour is expected, replace constructor with newFixedPoolExecutor() to avoid confusion
> 2) If pool is expected to resize only from corePoolSize to maximumPoolSize, SynchronousQueue can be used - but it will reject tasks if maximum amount of threads is already created. We can use Integer.MAXIMUM as maximumPoolSize or introduce a custom queue to avoid this 
> 3) If pool is expected to resize from 0 to maximumPoolSize, allowCoreThreadTimeout should be used
>  
> Example of incorrect usage:
> {code:java}
> tableIoExecutor = new ThreadPoolExecutor( Math.min(cpus * 3, 25), Integer.MAX_VALUE, 100, MILLISECONDS, new LinkedBlockingQueue<>(), IgniteThreadFactory.create(nodeName, "tableManager-io", LOG, STORAGE_READ, STORAGE_WRITE));{code}
> From ThreadPoolExecutor documentation:
> (for example a LinkedBlockingQueue without a predefined capacity will cause new tasks to wait in the queue when all corePoolSize threads are busy. Thus, no more than corePoolSize threads will ever be created. (And the value of the maximumPoolSize therefore doesn't have any effect.)
> By default, the keep-alive policy applies only when there are more than corePoolSize threads, but method #allowCoreThreadTimeOut(boolean) can be used to apply this time-out policy to core threads as well, so long as the keepAliveTime value is non-zero.



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