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From "Adam Kramer (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-2327) UDFs should be made aware of their arguments are constants.
Date Sun, 31 Jul 2011 22:53:09 GMT
UDFs should be made aware of their arguments are constants.
-----------------------------------------------------------

                 Key: HIVE-2327
                 URL: https://issues.apache.org/jira/browse/HIVE-2327
             Project: Hive
          Issue Type: Improvement
            Reporter: Adam Kramer


There are a lot of UDFs which would show major performance differences if one assumes that
some of its arguments are constant.

Consider, for example, any UDF that takes a regular expression as input: This can be complied
once (fast) if it's a constant, or once per row (wicked slow) if it's not a constant.

Or, consider any UDF that reads from a file and/or takes a filename as input; it would have
to re-read the whole file if the filename changes.

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