[jira] [Commented] (HIVE-2327) UDFs should be made aware when their arguments are constants.

["John Sichi (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-2327?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13073655#comment-13073655 ] 

John Sichi commented on HIVE-2327:
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Is this different from HIVE-1360?


> UDFs should be made aware when 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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