[ https://issues.apache.org/jira/browse/HIVE-19847?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
BELUGA BEHR updated HIVE-19847: ------------------------------- Attachment: HIVE-19847.3.patch > 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 > > > 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. -- This message was sent by Atlassian JIRA (v7.6.3#76005)