[jira] [Updated] (HIVE-26428) Limit usage of LLAP BPWrapper to threads of IO threadpools

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-26428?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated HIVE-26428:
----------------------------------
    Labels: pull-request-available  (was: )

> Limit usage of LLAP BPWrapper to threads of IO threadpools
> ----------------------------------------------------------
>
>                 Key: HIVE-26428
>                 URL: https://issues.apache.org/jira/browse/HIVE-26428
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Ádám Szita
>            Assignee: Ádám Szita
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> BPWrapper is used in LRFU cache eviction policy to decrease the time spent waiting for lock on the heap. This is done by adding a buffer as threadlocal and accumulating CacheableBuffer instances there before trying to acquire a lock. This works well when we have threads from pools such as IO-Elevator threads or OrcEncode threads.
> For ephemeral threads there's no advantage of doing this as the buffers in threadlocals may never reach the heap or list structures of LRFU, thereby also making evictions less efficient. This can happen e.g. LLAPCacheAwareFS is used with Parquet, where we're using the Tez threads for both execution and IO.
> We should disable BPWrappers for such cases.



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