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From "Laljo John Pullokkaran (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-9035) CBO: Disable PPD when functions are non-deterministic (ppd_random.q - non-deterministic udf rand() pushed above join)
Date Thu, 11 Dec 2014 23:50:13 GMT

    [ https://issues.apache.org/jira/browse/HIVE-9035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14243382#comment-14243382
] 

Laljo John Pullokkaran commented on HIVE-9035:
----------------------------------------------

Calcite doesn't want to restrict itself in this way (had discussions with Julian on this).
This is a hive specific (may be Facebook specific) design choice. Theoretically if a function
is non deterministic the output relation coming out of that filter will be non deterministic
as well; hence it should be ok to push these filters down. However since Hive has this specific
behavior we want to adhere to this behavior only for hive.

> CBO: Disable PPD when functions are non-deterministic (ppd_random.q  - non-deterministic
udf rand() pushed above join)
> ----------------------------------------------------------------------------------------------------------------------
>
>                 Key: HIVE-9035
>                 URL: https://issues.apache.org/jira/browse/HIVE-9035
>             Project: Hive
>          Issue Type: Sub-task
>          Components: CBO
>            Reporter: Sergey Shelukhin
>            Assignee: Laljo John Pullokkaran
>             Fix For: 0.15.0
>
>         Attachments: HIVE-9035.patch
>
>
> Not clear if this is a problem. Probably issue is in Optiq if it is, does it know the
UDF is non-deterministic? We could disable Optiq for such UDFs if all else fails.



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