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https://issues.apache.org/jira/browse/HIVE-19847?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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BELUGA BEHR updated HIVE-19847:
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Status: Open (was: Patch Available)
> Create Separate getInputSummary Service
> ---------------------------------------
>
> Key: HIVE-19847
> URL: https://issues.apache.org/jira/browse/HIVE-19847
> Project: Hive
> Issue Type: Improvement
> Components: HiveServer2
> Affects Versions: 3.0.0, 4.0.0
> Reporter: BELUGA BEHR
> Assignee: BELUGA BEHR
> Priority: Major
> Attachments: HIVE-19847.1.patch, HIVE-19847.2.patch,
> HIVE-19847.3.patch, HIVE-19847.4.patch, HIVE-19847.5.patch, HIVE-19847.6.patch
>
>
> The Hive {{org.apache.hadoop.hive.ql.exec.Utilities.java}} file has taken on
> a life of its own. We should consider separating out the various components
> into their own classes. For this ticket, I propose separating out the
> {{getInputSummary}} functionality into its own class.
> There are several issues with the current implementation:
> # It is
> [synchronized|https://github.com/apache/hive/blob/f27c38ff55902827499192a4f8cf8ed37d6fd967/ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java#L2383].
> Only one query can get file input summary at a time. For a query which
> deals with a large data set with a large number of files, this can block
> other queries for a long period of time. This is especially painful when
> most queries use a small data set, but a large data set is submitted on
> occasion.
> # For each query, time is spend setting up and tearing down a ThreadPool
> # It uses deprecated code
> I propose breaking it out into its own class and creating a single thread
> pool that all queries pull from. In this way, the bottle neck will be one
> the number of available threads, not on a single query and if a big query is
> running and a small query is also submitted, the smaller query will be able
> to proceed.
> In regards to setup/teardown... if a query uses 15 threads to perform this
> summary action, then finishes, it will tear down the threads, the next query
> may immediate create 15 new threads for processing. With a single pool,
> those threads are never performing tear down and setup.
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