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https://issues.apache.org/jira/browse/HIVE-18421?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16321352#comment-16321352
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Gopal V commented on HIVE-18421:
--------------------------------
New Column vectors are generally a bad idea - OOB checks are much easier to
apply to Long.
I'm expecting that we'll add something like a
{code}
if (checked) {
checkBounds(outV, typeRange);
}
{code}
to
https://github.com/apache/hive/blob/master/ql/src/gen/vectorization/ExpressionTemplates/ColumnArithmeticColumn.txt
This allows the initial operation to be SIMD and the checking to be L1 cache
efficient (i.e check & overwrite same memory).
> Vectorized execution does not handle integer overflows
> ------------------------------------------------------
>
> Key: HIVE-18421
> URL: https://issues.apache.org/jira/browse/HIVE-18421
> Project: Hive
> Issue Type: Bug
> Components: Vectorization
> Affects Versions: 2.1.1, 2.2.0, 3.0.0, 2.3.2
> Reporter: Vihang Karajgaonkar
> Assignee: Vihang Karajgaonkar
>
> In vectorized execution arithmetic operations which cause integer overflows
> can give wrong results. Issue is reproducible in both Orc and parquet.
> Simple test case to reproduce this issue
> {noformat}
> set hive.vectorized.execution.enabled=true;
> create table parquettable (t1 tinyint, t2 tinyint) stored as parquet;
> insert into parquettable values (-104, 25), (-112, 24), (54, 9);
> select t1, t2, (t1-t2) as diff from parquettable where (t1-t2) < 50 order by
> diff desc;
> +-------+-----+-------+
> | t1 | t2 | diff |
> +-------+-----+-------+
> | -104 | 25 | 127 |
> | -112 | 24 | 120 |
> | 54 | 9 | 45 |
> +-------+-----+-------+
> {noformat}
> When vectorization is turned off the same query produces only one row.
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