[jira] [Comment Edited] (HIVE-21388) Constant UDF is not pushed to JDBCStorage Handler

["Jesus Camacho Rodriguez (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-21388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16784584#comment-16784584 ] 

Jesus Camacho Rodriguez edited comment on HIVE-21388 at 3/5/19 3:41 PM:
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[~jdere], could you review? Thanks


was (Author: jcamachorodriguez):
[~jdere], could you take a look? Thanks

> Constant UDF is not pushed to JDBCStorage Handler
> -------------------------------------------------
>
>                 Key: HIVE-21388
>                 URL: https://issues.apache.org/jira/browse/HIVE-21388
>             Project: Hive
>          Issue Type: Improvement
>          Components: CBO, StorageHandler
>    Affects Versions: 4.0.0
>            Reporter: Daniel Dai
>            Assignee: Jesus Camacho Rodriguez
>            Priority: Major
>         Attachments: HIVE-21388.01.patch, HIVE-21388.patch
>
>
> A query involve a Hive UDF which produce a constant value does not push to JDBC table. Replacing the UDF with a constant push down works. Ideally, Hive shall first do constant folding and then push the computation.
> Here is the example:
> {code}
> explain select PRINCIPAL_NAME from sys.TBL_PRIVS where PRINCIPAL_NAME=current_user();
> +----------------------------------------------------+
> |                      Explain                       |
> +----------------------------------------------------+
> | Plan optimized by CBO.                             |
> |                                                    |
> | Stage-0                                            |
> |   Fetch Operator                                   |
> |     limit:-1                                       |
> |     Select Operator [SEL_3]                        |
> |       Output:["_col0"]                             |
> |       Filter Operator [FIL_2]                      |
> |         predicate:(_col5 = 'hrt_qa')               |
> |         Select Operator [SEL_1]                    |
> |           Output:["_col5"]                         |
> |           TableScan [TS_0]                         |
> |             Output:["principal_name"],properties:{"hive.sql.query":"SELECT `tbl_grant_id`, `create_time`, `grant_option`, `grantor`, `grantor_type`, `principal_name`, `principal_type`, `tbl_priv`, `tbl_id`, `authorizer`\nFROM `TBL_PRIVS`","hive.sql.query.fieldNames":"tbl_grant_id,create_time,grant_option,grantor,grantor_type,principal_name,principal_type,tbl_priv,tbl_id,authorizer","hive.sql.query.fieldTypes":"bigint,int,int,string,string,string,string,string,bigint,string","hive.sql.query.split":"true"} |
> |                                                    |
> +----------------------------------------------------+
> {code}
> If I replace current_user() with a constant, the predicate is pushed to table scan.
> Also, setting annotation deterministic=true and make initialize() return a ConstantObjectInspector of GenericUDFCurrentUser does not make a difference.



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