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https://issues.apache.org/jira/browse/DRILL-520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16401459#comment-16401459
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Karthikeyan Manivannan commented on DRILL-520:
----------------------------------------------
This cannot be fixed simply by changing the return type of the builtin
functions (as suggested in the attached patch) because floating point types
(Float4, Float8) have a range that is beyond what can be represented in any
integer type, even in BigInt.
This is what happens if the patch (change the outputType of ceil/floor to Int
and use a (int) cast to return the value of java.lang.Math.ceil/floor) is
applied
0: jdbc:drill:zk=local> select floor(cast('340280000.5' as float));
| 340280000 |
1 row selected (0.157 seconds)
0: jdbc:drill:zk=local> select floor(cast('3402800000.5' as float)); <--- too
big to represent as Int
| 2147483647 | <----- Int max
A similar overflow will happen even if a BigInt output type and a 'double' cast
is used.
I looked up how ProsgreSQL implements ceil/floor:
|Name|Return Type|Description|Example|Result|
|{{ceil(dp}} or {{numeric}})|same as input)|nearest integer greater than or
equal to argument|{{ceil(-42.8)}}|{{-42}}|
|{{floor(dp}} or {{numeric}})|(same as input)|nearest integer less than or
equal to argument|{{floor(-42.8)}}|{{-43}}|
where
_*dp*_ is a double precision 8byte floating-point number
_*numeric*_ is numeric [ (p, s) ] exact numeric of selectable precision
I am not sure how a the dp/numeric return type is returned as an Int
I think the way to fix this in Drill would be to use BigDecimal as the return
type.
> ceiling/ceil and floor functions return decimal value instead of an integer
> ---------------------------------------------------------------------------
>
> Key: DRILL-520
> URL: https://issues.apache.org/jira/browse/DRILL-520
> Project: Apache Drill
> Issue Type: Bug
> Components: Functions - Drill
> Affects Versions: 1.0.0
> Reporter: Krystal
> Assignee: Karthikeyan Manivannan
> Priority: Critical
> Fix For: Future
>
> Attachments: DRILL-520.patch
>
>
> Ran the following queries in drill:
> 0: jdbc:drill:schema=dfs> select ceiling(55.8) from dfs.`student` where
> rownum=11;
> +------------+
> | EXPR$0 |
> +------------+
> | 56.0 |
> +------------+
> 0: jdbc:drill:schema=dfs> select floor(55.8) from dfs.`student` where
> rownum=11;
> +------------+
> | EXPR$0 |
> +------------+
> | 55.0 |
> +------------+
> The same queries executed from oracle, postgres and mysql returned integer
> values of 56 and 55.
> Found the following description of the two functions from
> http://users.atw.hu/sqlnut/sqlnut2-chp-4-sect-4.html :
> Ceil/Ceiling:
> Rounds a noninteger value upwards to the next greatest integer. Returns an
> integer value unchanged.
> Floor:
> Rounds a noninteger value downwards to the next least integer. Returns an
> integer value unchanged.
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