[ 
https://issues.apache.org/jira/browse/DRILL-6094?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16435914#comment-16435914
 ] 

Vitalii Diravka edited comment on DRILL-6094 at 4/12/18 4:58 PM:
-----------------------------------------------------------------

Looks like ARROW-61 is not an issue for Drill anymore.
 Drill 1.6.0 version:
{code:java}
SELECT CAST('922337203685477587' as DECIMAL(18, 0)) > CAST('0.1' as DECIMAL(18, 
1)) IS_FIRST_GREATER FROM (VALUES(1))
--------------------------------------
| IS_FIRST_GREATER<BIT(REQUIRED)>    |
--------------------------------------
| false                              |
--------------------------------------

select _DECIMAL_decimal18 > _DECIMAL_decimal18_2 IS_FIRST_GREATER, 
_DECIMAL_decimal18, _DECIMAL_decimal18_2 from 
dfs.`/tmp/parquet/drill/parquet_test_file_simple` t
----------------------------------------------------------------------------------------------------------------
| IS_FIRST_GREATER<BIT(REQUIRED)>        | _DECIMAL_decimal18<DECIMAL18(REQUI | 
_DECIMAL_decimal18_2<DECIMAL18(REQ |
----------------------------------------------------------------------------------------------------------------
| false                              | 922337203685477587                 | 0.1 
                               |
----------------------------------------------------------------------------------------------------------------
{code}
Current Drill master:
{code:java}
SELECT CAST('922337203685477587' as DECIMAL(18, 0)) > CAST('0.1' as DECIMAL(18, 
1)) IS_FIRST_GREATER FROM (VALUES(1))
----------------------------------------------------------------------------------------------------------------
IS_FIRST_GREATER<BIT(REQUIRED)>
true

select _DECIMAL_decimal18 > _DECIMAL_decimal18_2 IS_FIRST_GREATER, 
_DECIMAL_decimal18, _DECIMAL_decimal18_2" +
          " from dfs.root.`/tmp/parquet/drill/parquet_test_file_simple` t
----------------------------------------------------------------------------------------------------------------
IS_FIRST_GREATER<BIT(REQUIRED)>,_DECIMAL_decimal18<DECIMAL18(REQUIRED)>,_DECIMAL_decimal18_2<DECIMAL18(REQUIRED)>
true,922337203685477587,0.1
{code}
For the first query Calcite simplifies the predicaste in the project to true 
and for the second query casting to FLOAT8 is used now (and FLOAT8 values are 
compared).

Therefore _adjustScaleMultiply_ is still buggy and isn't needed anymore (after 
moving to VARDECIMAL) I would recommend to remove it from the project.


was (Author: vitalii):
Looks like ARROW-61 is not an issue for Drill anymore.
 Drill 1.6.0 version:
{code:java}
SELECT CAST('922337203685477587' as DECIMAL(18, 0)) > CAST('0.1' as DECIMAL(18, 
1)) IS_FIRST_GREATER FROM (VALUES(1))
--------------------------------------
| IS_FIRST_GREATER<BIT(REQUIRED)>    |
--------------------------------------
| false                              |
--------------------------------------

select _DECIMAL_decimal18 > _DECIMAL_decimal18_2 IS_FIRST_GREATER, 
_DECIMAL_decimal18, _DECIMAL_decimal18_2 from 
dfs.`/tmp/parquet/drill/parquet_test_file_simple` t
----------------------------------------------------------------------------------------------------------------
| IS_FIRST_GREATER<BIT(REQUIRED)>        | _DECIMAL_decimal18<DECIMAL18(REQUI | 
_DECIMAL_decimal18_2<DECIMAL18(REQ |
----------------------------------------------------------------------------------------------------------------
| false                              | 922337203685477587                 | 0.1 
                               |
----------------------------------------------------------------------------------------------------------------
{code}
Current Drill master:
{code:java}
SELECT CAST('922337203685477587' as DECIMAL(18, 0)) > CAST('0.1' as DECIMAL(18, 
1)) IS_FIRST_GREATER FROM (VALUES(1))
----------------------------------------------------------------------------------------------------------------
IS_FIRST_GREATER<BIT(REQUIRED)>
true

select _DECIMAL_decimal18 > _DECIMAL_decimal18_2 IS_FIRST_GREATER, 
_DECIMAL_decimal18, _DECIMAL_decimal18_2" +
          " from dfs.root.`/tmp/parquet/drill/parquet_test_file_simple` t
----------------------------------------------------------------------------------------------------------------
IS_FIRST_GREATER<BIT(REQUIRED)>,_DECIMAL_decimal18<DECIMAL18(REQUIRED)>,_DECIMAL_decimal18_2<DECIMAL18(REQUIRED)>
true,922337203685477587,0.1
{code}
For the first query Calcite simplifies the predicaste in the project to true 
and for the second query casting to FLOAT8 is used now (and FLOAT8 values are 
compared).

Therefore _adjustScaleMultiply_ is still buggy and isn't needed anymore (after 
moving to VARDECIMAL) I recommend to remove it from the project.

> Decimal data type enhancements
> ------------------------------
>
>                 Key: DRILL-6094
>                 URL: https://issues.apache.org/jira/browse/DRILL-6094
>             Project: Apache Drill
>          Issue Type: Improvement
>    Affects Versions: 1.12.0
>            Reporter: Volodymyr Vysotskyi
>            Assignee: Volodymyr Vysotskyi
>            Priority: Major
>
> Currently, Decimal types are disabled by default since existing Decimal 
> implementation has a lot of flaws and performance problems. The goal of thisĀ 
> Jira to describe majority of them and possible ways of improving existing 
> implementation to be able to enable Decimal data types by default.



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