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https://issues.apache.org/jira/browse/PHOENIX-4283?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16204396#comment-16204396
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Ethan Wang edited comment on PHOENIX-4283 at 10/14/17 1:27 AM:
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So in the GroupbyCompiler, when nested groupby is evaluated, in this case it
will try to coarse all the leading ProjectedColumnExpressions (except the last
one) inside the expressions to the required types. e.g., for (A,C) it will be
(A); for (A,B,C,D,E) it will be (A,B,C,D) force to convert.
When doing so, in IndexUtil.getIndexColumnDataType(), BigInt (PLong) is defined
to be coarsable with PDecimal. (in PLong.isComparableTo() ). As a result, all
the leading BIGINT ProjectedColumnExpressions is now casted to decimal. The
Decimal will be converted back to the appropriate type (Integer or Long).
If I understand right the reason behind this is that it needs something to give
coprocessor sort by in the case groupbys is not along the PK axis. However,
when a region have no such groupbys, it need null to hold on. And decimal is
the "appropriate" type that we can construct a such a null. Is this correct?
was (Author: aertoria):
So in the GroupbyCompiler, when nested groupby is evaluated, it will try to
coarse all the leading ProjectedColumnExpressions (except the last one)
inside the expressions to the required types. e.g., for (A,C) it will be (A);
for (A,B,C,D,E) it will be (A,B,C,D) force to convert.
When doing so, in IndexUtil.getIndexColumnDataType(), BigInt (PLong) is defined
to be coarsable with PDecimal. (in PLong.isComparableTo() ). As a result, all
the leading BIGINT ProjectedColumnExpressions is now casted to decimal. The
Decimal will be converted back to the appropriate type (Integer or Long).
If I understand right the reason behind this is that it needs something to give
coprocessor sort by in the case groupbys is not along the PK axis. However,
when a region have no such groupbys, it need null to hold on. And decimal is
the "appropriate" type that we can construct a such a null. Is this correct?
> Group By statement truncating BIGINTs
> -------------------------------------
>
> Key: PHOENIX-4283
> URL: https://issues.apache.org/jira/browse/PHOENIX-4283
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.11.0
> Reporter: Steven Sadowski
> Assignee: Ethan Wang
> Fix For: 4.12.1
>
>
> *Versions:*
> Phoenix 4.11.0
> HBase: 1.3.1
> (Amazon EMR: 5.8.0)
> *Steps to reproduce:*
> 1. From the `sqlline-thin.py` client setup the following table:
> {code:sql}
> CREATE TABLE test_table (
> a BIGINT NOT NULL,
> c BIGINT NOT NULL
> CONSTRAINT PK PRIMARY KEY (a, c)
> );
> UPSERT INTO test_table(a,c) VALUES(4444444444444444444, 5555555555555555555);
> SELECT a FROM (SELECT a, c FROM test_table GROUP BY a, c) GROUP BY a, c;
> {code}
> *Expected Result:*
> {code:sql}
> +----------------------+
> | A |
> +----------------------+
> | 4444444444444444444 |
> +----------------------+
> {code}
> *Actual Result:*
> {code:sql}
> +----------------------+
> | A |
> +----------------------+
> | 4444444444444000000 |
> +----------------------+
> {code}
> *Comments:*
> Having the two Group By statements together seems to truncate the last 6 or
> so digits of the final result. Removing the outer (or either) group by will
> produce the correct result.
> Please fix the Group by statement to not truncate the outer result's value.
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