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https://issues.apache.org/jira/browse/HIVE-372?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zheng Shao updated HIVE-372:
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Attachment: HIVE-372.2.patch
This attached patch contains changed output files.
There is one regression - "CREATE TABL test ..." is reporting error in "CREATE"
now. I tried to fix that but I didn't succeed. It probably needs much more
effort. Basically, we may see this kind of problems for any consecutive
keywords.
However this patch does detect a lot of the syntax errors much better than
before (See other new/changed test cases), so I still think we should still
include this in 0.3.
> Nested UDFs cause _very_ high memory usage when processing query
> ----------------------------------------------------------------
>
> Key: HIVE-372
> URL: https://issues.apache.org/jira/browse/HIVE-372
> Project: Hadoop Hive
> Issue Type: Bug
> Components: Query Processor
> Environment: Fedora Linux, 10x Amazon EC2 (Large Instance w/ 8GB Ram)
> Reporter: Steve Corona
> Attachments: HIVE-372.1.patch, HIVE-372.2.patch
>
>
> When nesting UDFs, the Hive Query processor takes a large amount of
> time+memory to process the query. For example, I ran something along the
> lines of:
> select trim( trim( trim(trim( trim( trim( trim( trim( trim(column)))))))))
> from test_table;
> This query needs 10GB+ of memory to process before it'll launch the job. The
> amount of memory increases exponentially with each nested UDF.
> Obviously, I am using trim() in this case as a simple example that causes the
> same problem to occur. In my actual use-case I had a bunch of nested
> regexp_replaces.
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