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Posted to issues@hive.apache.org by "Prasanth Jayachandran (JIRA)" <ji...@apache.org> on 2015/08/06 02:31:05 UTC
[jira] [Updated] (HIVE-11477) CBO inserts a UDF cast for integer
type promotion (only for negative numbers)
[ https://issues.apache.org/jira/browse/HIVE-11477?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Prasanth Jayachandran updated HIVE-11477:
-----------------------------------------
Summary: CBO inserts a UDF cast for integer type promotion (only for negative numbers) (was: CBO inserts a UDF cast for integer type promotion)
> CBO inserts a UDF cast for integer type promotion (only for negative numbers)
> -----------------------------------------------------------------------------
>
> Key: HIVE-11477
> URL: https://issues.apache.org/jira/browse/HIVE-11477
> Project: Hive
> Issue Type: Bug
> Affects Versions: 2.0.0
> Reporter: Prasanth Jayachandran
> Assignee: Pengcheng Xiong
>
> When CBO is enabled, filters which compares tinyint, smallint columns with constant integer types will insert a UDFToInteger cast for the columns. When CBO is disabled, there is no such UDF. This behaviour breaks ORC predicate pushdown feature as ORC ignores UDFs in the filters.
> In the following examples column t is tinyint
> {code:title=Explain for select count(*) from orc_ppd where t < -127; (CBO OFF)}
> Filter Operator [FIL_9]
> predicate:(t = 125) (type: boolean)
> Statistics:Num rows: 1050 Data size: 611757 Basic stats: COMPLETE Column stats: NONE
> TableScan [TS_0]
> alias:orc_ppd
> Statistics:Num rows: 2100 Data size: 1223514 Basic stats: COMPLETE Column stats: NONE
> {code}
> {code:title=Explain for select count(*) from orc_ppd where t < -127; (CBO ON)}
> Filter Operator [FIL_10]
> predicate:(UDFToInteger(t) < -127) (type: boolean)
> Statistics:Num rows: 700 Data size: 407838 Basic stats: COMPLETE Column stats: NONE
> TableScan [TS_0]
> alias:orc_ppd
> Statistics:Num rows: 2100 Data size: 1223514 Basic stats: COMPLETE Column stats: NONE
> {code}
> CBO does not insert such cast for non-negative numbers
> {code:title=Explain for select count(*) from orc_ppd where t < 127; (CBO ON)}
> Filter Operator [FIL_10]
> predicate:(t < 127) (type: boolean)
> Statistics:Num rows: 700 Data size: 407838 Basic stats: COMPLETE Column stats: NONE
> TableScan [TS_0]
> alias:orc_ppd
> Statistics:Num rows: 2100 Data size: 1223514 Basic stats: COMPLETE Column stats: NONE
> {code}
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