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https://issues.apache.org/jira/browse/IMPALA-8205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17694437#comment-17694437
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ASF subversion and git services commented on IMPALA-8205:
---------------------------------------------------------
Commit 7c854e117be659abdfed4ead43df75e5903d9132 in impala's branch
refs/heads/master from stiga-huang
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=7c854e117 ]
IMPALA-11953: Declare num_trues and num_falses in TIntermediateColumnStats as
optional
TIntermediateColumnStats is the representation of incremental stats
which are stored in HMS partition properties using keys like
"impala_intermediate_stats_chunk0", "impala_intermediate_stats_chunk1",
"impala_intermediate_stats_chunk2", etc.
Fields in TIntermediateColumnStats should be optional to ensure
backward compatibility. IMPALA-8205 adds two required fields, num_trues
and num_falses, in TIntermediateColumnStats. This breaks the incremental
stats loading in higher versions of Impala if the stats are generated by
older Impala versions (< 4.0). This patch changes the fields to be
optional.
Tests:
- Verified the incremental stats generated by CDH Impala cluster can be
loaded by CDP Impala cluster with this fix.
Change-Id: I4f74d5d0676e7ce9eb4ea8061a15610846db3ca5
Reviewed-on: http://gerrit.cloudera.org:8080/19555
Reviewed-by: Riza Suminto <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
> Illegal statistics for numFalse and numTrue
> -------------------------------------------
>
> Key: IMPALA-8205
> URL: https://issues.apache.org/jira/browse/IMPALA-8205
> Project: IMPALA
> Issue Type: Bug
> Components: Catalog
> Reporter: wuchang
> Assignee: wuchang
> Priority: Major
> Labels: impala, numFalse, numTrue, statistics
> Fix For: Impala 4.0.0
>
>
> 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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