[
https://issues.apache.org/jira/browse/PARQUET-2244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17689729#comment-17689729
]
ASF GitHub Bot commented on PARQUET-2244:
-----------------------------------------
zhongyujiang commented on PR #1028:
URL: https://github.com/apache/parquet-mr/pull/1028#issuecomment-1433005114
> I don't know if there is a downstream that relies on Parquet judge value
<> null as TRUE instead of UNKNOW, I guess that might be in some non-ansi
standard engines.
I just want to make sure it's safe to revert this, I did some search and
find this:
https://stackoverflow.com/questions/129077/null-values-inside-not-in-clause
Seems SQL Server 2005 has a switch `ansi_null` to control wheather the
result of `value <> null` is `TRUE` or `UNKNOWN`, when `ansi_nulls` is off,
`3 <> null` is true. Though I didn't find such a switch in engines like Hive or
Spark. Do you have any comments on this? Or do you think it's worth caring
about? @gszadovszky @wgtmac @huaxingao.
> Dictionary filter may skip row-groups incorrectly when evaluating notIn
> -----------------------------------------------------------------------
>
> Key: PARQUET-2244
> URL: https://issues.apache.org/jira/browse/PARQUET-2244
> Project: Parquet
> Issue Type: Bug
> Components: parquet-mr
> Affects Versions: 1.12.2
> Reporter: Yujiang Zhong
> Assignee: Yujiang Zhong
> Priority: Major
>
> Dictionary filter may skip row-groups incorrectly when evaluating `notIn` on
> optional columns with null values. Here is an example:
> Say there is a optional column `c1` with all pages dict encoded, `c1` has and
> only has two distinct values: ['foo', null], and the predicate is `c1 not
> in ('foo', 'bar')`.
> Now dictionary filter may skip this row-group that is actually should not be
> skipped, because there are nulls in the column.
>
> This is a bug similar to #1510.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
