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https://issues.apache.org/jira/browse/HIVE-9277?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14372407#comment-14372407
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Sergey Shelukhin commented on HIVE-9277:
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WRT logger, I meant why not create a separate logger if you need logger prefix?
Logger logs class name it was created with, and can be configured by class to
filter out messages, set level, etc.
Why reinvent this in each log message?
Can be fixed on commit, +1
> Hybrid Hybrid Grace Hash Join
> -----------------------------
>
> Key: HIVE-9277
> URL: https://issues.apache.org/jira/browse/HIVE-9277
> Project: Hive
> Issue Type: New Feature
> Components: Physical Optimizer
> Reporter: Wei Zheng
> Assignee: Wei Zheng
> Labels: join
> Attachments: HIVE-9277.01.patch, HIVE-9277.02.patch,
> HIVE-9277.03.patch, HIVE-9277.04.patch, HIVE-9277.05.patch,
> HIVE-9277.06.patch, HIVE-9277.07.patch, HIVE-9277.08.patch,
> HIVE-9277.13.patch, HIVE-9277.14.patch,
> High-leveldesignforHybridHybridGraceHashJoinv1.0.pdf
>
>
> We are proposing an enhanced hash join algorithm called _“hybrid hybrid grace
> hash join”_.
> We can benefit from this feature as illustrated below:
> * The query will not fail even if the estimated memory requirement is
> slightly wrong
> * Expensive garbage collection overhead can be avoided when hash table grows
> * Join execution using a Map join operator even though the small table
> doesn't fit in memory as spilling some data from the build and probe sides
> will still be cheaper than having to shuffle the large fact table
> The design was based on Hadoop’s parallel processing capability and
> significant amount of memory available.
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