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https://issues.apache.org/jira/browse/HIVE-9035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14243382#comment-14243382
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Laljo John Pullokkaran commented on HIVE-9035:
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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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