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https://issues.apache.org/jira/browse/IMPALA-13555?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17951537#comment-17951537
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ASF subversion and git services commented on IMPALA-13555:
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Commit bc0de109668934e2feb4f3f8fa83c335eabe80ba in impala's branch
refs/heads/master from Surya Hebbar
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=bc0de1096 ]
IMPALA-14069: Factor possibility of zero timestamps in aggregated event
sequences
Currently, the missing event timestamps are substituted by zeros
and then reported(i.e. unreported_event_instance_idxs) within
event sequences of the JSON profile. See IMPALA-13555 for more details.
Even with micro/nanosecond precision, some event timestamps are recorded
as zeros (i.e. Prepare Finished - 0ns).
The current implementation of aggregated event sequences was incorrectly
considering these zeros as substituted missing timestamps.
Although, these can be distinguished from missing timestamps through
the exposed 'unreported_event_instance_idxs', it is more helpful
to represent missing values as -ve values or constants(i.e. -1).
This representation is favorable for summary and visualization, and is
necessary for skipping missing values and maintaing alignment between
instance timestamps.
The patch also fixes null values in "info_strings" fields within
the JSON profile.
Fixed runtime-profile-test to consider -ve values(i.e. -1) as missing
event timestamps, instead of 0.
Updated the generated profiles in testdata/impala-profiles.
Change-Id: I9f1efd2aad5f62084075cd8f9169ef72c66942b6
Reviewed-on: http://gerrit.cloudera.org:8080/22893
Reviewed-by: Riza Suminto <[email protected]>
Tested-by: Riza Suminto <[email protected]>
> Enhance order and predictability of reported events in EventSequence
> --------------------------------------------------------------------
>
> Key: IMPALA-13555
> URL: https://issues.apache.org/jira/browse/IMPALA-13555
> Project: IMPALA
> Issue Type: Improvement
> Reporter: Surya Hebbar
> Priority: Major
>
> In some cases, when the instances responsible for generating 'labels' map
> have missing events, it is functionally not possible to extract the perfect
> order.
> The current event aggregation mechanism, fails to provide an absolute method
> to align and order the missing events' timestamp in many edge cases.
> It would be great to enhance EventSequence's constructor and the collection
> mechanism along with a cleanup and performance boost provided by switching to
> a completed version of profile V2.
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