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https://issues.apache.org/jira/browse/IMPALA-8205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16770002#comment-16770002
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wuchang commented on IMPALA-8205:
---------------------------------
[~tarmstrong] was it possible that just do not calculate the boolean statistics
data? I find that the
{code:java}
BooleanColumnStatsData{code}
is not required in
{code:java}
ColumnStatisticsData{code}
Below is the ColumnStatisticsData definition:
{code:java}
union ColumnStatisticsData {
1: BooleanColumnStatsData booleanStats,
2: LongColumnStatsData longStats,
3: DoubleColumnStatsData doubleStats,
4: StringColumnStatsData stringStats,
5: BinaryColumnStatsData binaryStats,
6: DecimalColumnStatsData decimalStats,
7: DateColumnStatsData dateStats
}
{code}
> Illegal statistics for numFalse and numTrue
> -------------------------------------------
>
> Key: IMPALA-8205
> URL: https://issues.apache.org/jira/browse/IMPALA-8205
> Project: IMPALA
> Issue Type: Bug
> Reporter: wuchang
> Priority: Major
> Labels: impala, numFalse, numTrue, statistics
>
> When impala compute statistics, it set *numFalse = -1* and *numTrue = 1* when
> the statistic is missing;
> *-1* for *numFalse* will corrupt some query engine like Presto and there
> already exists some PR report and hotfix it :
> [presto-11859|https://github.com/prestodb/presto/pull/11859]
> *1* for *numTrue* is also unreasonable because we are not sure whether it
> indicates the real numTrue statistics or a missing statistics;
> Also, previously , the *nullCount* also use -1 to indicate its absence which
> also caused problem for Presto. Presto has to add a hotfix for
> it([presto-11549|https://github.com/prestodb/presto/pull/11549]) . But it is
> a fortunate that impala has fixed this bug;
> It is necessary to set to null when these statistics are absent instead of -1
> and 1.
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