[jira] [Commented] (IGNITE-24323) Calcite engine. Query execution inside UDF leads to deadlock

["Ignite TC Bot (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-24323?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18103574#comment-18103574 ] 

Ignite TC Bot commented on IGNITE-24323:
----------------------------------------

Docs-required triage: removed only the Docs Required flag because the linked documentation follow-up IGNITE-24401 is complete and merged in PR #13248 / commit 9d67e0d13499f7408feddd93a749a7ff0d687a81. Verified locally on current master: the Calcite code has the IGNITE_CALCITE_USE_QUERY_BLOCKING_TASK_EXECUTOR switch and QueryBlockingTaskExecutor, and docs/_docs/SQL/custom-sql-func.adoc documents nested SQL queries from UDFs plus the required query thread pool sizing. Release Notes Required was preserved.

> Calcite engine. Query execution inside UDF leads to deadlock
> ------------------------------------------------------------
>
>                 Key: IGNITE-24323
>                 URL: https://issues.apache.org/jira/browse/IGNITE-24323
>             Project: Ignite
>          Issue Type: Bug
>            Reporter: Aleksey Plekhanov
>            Assignee: Aleksey Plekhanov
>            Priority: Major
>              Labels: calcite, ise
>             Fix For: 2.18
>
>          Time Spent: 50m
>  Remaining Estimate: 0h
>
> We have striped executor to execute query tasks. Thread for query/fragment on each node is fixed and defined by hash of query ID and fragment ID. If user created user defined function and try to execute some query inside it, it can lead to deadlock, since task execution thread blocked by new synchronous query execution request and the new query can be assigned to the same thread.
> For H2-based SQL engine threads are no binded to the query and there is no such problem.
> For Calcite-based SQL engine we use non thread safe datastructures in tasks. 
> To workaround this problem we can use regular IgniteThreadPoolExecutor, but need to ensure that there are no tasks concurrently executing for the same query/fragment.
> Also, perhaps this approach can affect performance and should be enabled by some property explicitly only for users that require this mode. 
>   



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