[jira] [Updated] (IGNITE-27871) High latency for locally deployed tasks when peerClassLoadingEnabled=true (deployment lookup contention)

["Oleg Valuyskiy (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-27871?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Oleg Valuyskiy updated IGNITE-27871:
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    Summary: High latency for locally deployed tasks when peerClassLoadingEnabled=true (deployment lookup contention)  (was: Local deployment cache miss when peerClassLoadingEnabled=true leads to repeated synchronized deploy() calls)

> High latency for locally deployed tasks when peerClassLoadingEnabled=true (deployment lookup contention)
> --------------------------------------------------------------------------------------------------------
>
>                 Key: IGNITE-27871
>                 URL: https://issues.apache.org/jira/browse/IGNITE-27871
>             Project: Ignite
>          Issue Type: Bug
>            Reporter: Oleg Valuyskiy
>            Assignee: Oleg Valuyskiy
>            Priority: Major
>              Labels: ise
>
> When a Compute task is executed from a thin client and the task class is available in the node classpath (e.g. placed in libs directory),
> *GridDeploymentManager#getLocalDeployment* creates *GridDeploymentMetadata* without *classLoader* and {*}classLoaderId{*}.
> *GridDeploymentLocalStore#getDeployment(meta)* first attempts to find an existing deployment via {*}deployment(meta){*}. However, *deployment(meta)* matches cached deployments only if:
> {code:java}
> dep.classLoaderId() == meta.classLoaderId() || dep.classLoader() == meta.classLoader(){code}
> Since both *meta.classLoader* and *meta.classLoaderId* are null, the cached local deployment can never be matched.
> As a result, *GridDeploymentLocalStore#deploy(...)* is invoked on every task execution. This method is synchronized and performs additional lookup and bookkeeping logic, which introduces unnecessary contention and latency under high load.
> The issue is reproducible with:
>  * peerClassLoadingEnabled = true
>  * task class present in node classpath (libs)
>  * thin client executing the same task repeatedly by name
> However, when {*}peerClassLoadingEnabled=false{*}, *GridDeploymentManager* initializes *locDep* and reuses it directly, bypassing {*}GridDeploymentLocalStore{*}, which avoids this problem.



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