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https://issues.apache.org/jira/browse/IMPALA-11961?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17743092#comment-17743092
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ASF subversion and git services commented on IMPALA-11961:
----------------------------------------------------------
Commit 14a5e9a20af59af7a03a9fb480c077d1d8a38187 in impala's branch
refs/heads/master from Daniel Becker
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=14a5e9a20 ]
IMPALA-12239: BitWidthZeroRepeated seems to be flaky
RleTest.BitWidthZeroRepeated seems to be flaky in release builds. A
possible error message is this:
Value of: 0 Expected: val Which is: '\x9F' (159)
Stacktrace
.../Impala/be/src/util/rle-test.cc:410
Value of: 0
Expected: val
Which is: '\x9F' (159)
The problem seems to be around this 'memcpy()' call:
https://github.com/apache/impala/blob/3e9408480c5285ca925576b7486b35593407a32a/be/src/util/bit-stream-utils.inline.h#L237.
We're almost certainly running into undefined behaviour because
- the error only occurs in release mode, not in debug mode (not even in
ASAN or UBSAN mode)
- if we add something around the 'memcpy()', for example printing
'buffer_pos_' or 'v', the error doesn't occur
- the value with which the test fails, i.e. the value it reads instead
of the expected 0 is non-deterministic.
The failure occurs since https://gerrit.cloudera.org/#/c/20073/
(IMPALA-11961/IMPALA-12207: Add Redhat 9 / Ubuntu 22 support), which
upgraded gperftools.
We couldn't find the root cause of the bug but the most probable
possibilities are the following:
- there's a bug in Impala that leads to undefined behaviour and that
manifests in the test failure with the new gperftools version but not
with the old one
- there's a bug in the new gperftools version (2.10).
Downgrading gperftools is not an option because it is necessary for
Redhat 9 and Ubuntu 22. There is a workaround that causes the test to
pass - putting the 'memcpy()' in a conditional block:
if (LIKELY(buffer_pos_ != buffer_end_)) {
memcpy(v, buffer_pos_, num_bytes);
buffer_pos_ += num_bytes;
} else {
...
}
This most probably does not address the root cause, however; for more
see the Jira ticket.
Testing:
- manually verified that the test RleTest.BitWidthZeroRepeated passes
in a release build
Change-Id: I84645271101b4bd594dd25929924a3549c223244
Reviewed-on: http://gerrit.cloudera.org:8080/20187
Reviewed-by: Joe McDonnell <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
> Add support for Ubuntu 22.04
> ----------------------------
>
> Key: IMPALA-11961
> URL: https://issues.apache.org/jira/browse/IMPALA-11961
> Project: IMPALA
> Issue Type: New Feature
> Components: Infrastructure
> Reporter: Quanlong Huang
> Assignee: Joe McDonnell
> Priority: Major
> Fix For: Impala 4.3.0
>
>
> This tracks the support for Ubuntu 22.04. We should ensure the toolchain can
> build on it first.
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