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https://issues.apache.org/jira/browse/HBASE-25052?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17198426#comment-17198426
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Rushabh Shah commented on HBASE-25052:
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> Rushabh Shah you can provide higher bound of region with constructor.
Thank you [~vjasani] ! I understand the fix. But the same tests were passing in
branch-1.3 and now failing in branch-1.6.
At my dayjob, I extended MutableRangeHistogram (MutableSizeHistogram and
MutableTimeHistogram) in [Phoenix|https://github.com/apache/phoenix] project
and created some histogram metrics. It is still in our internal repo (haven't
open sourced yet but plan to do it shortly). I wrote some tests for that which
were running fine in branch-1.3 but now once we upgraded to branch-1.6 it
started failing.
Also MutableTimeHistogram doesn't expose any constructor to pass in maxExpected
value.
[MutableTimeHistogram|https://github.com/apache/hbase/blob/master/hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/MutableTimeHistogram.java#L37]
calls
[MutableRangeHistogram|https://github.com/apache/hbase/blob/master/hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/MutableRangeHistogram.java#L38]
which in turn calls
[MutableHistogram|https://github.com/apache/hbase/blob/master/hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/MutableHistogram.java#L47]
which calls empty constructor HistogramImpl.
Also due to many other limitations of FastLongHistogram, internally we decided
to move to [HdrHistogram|https://github.com/HdrHistogram/HdrHistogram] so this
is not a pressing issue for me personally but good to evaluate other hbase
histogram metrics after the change.
> FastLongHistogram#getCountAtOrBelow method is broken.
> -----------------------------------------------------
>
> Key: HBASE-25052
> URL: https://issues.apache.org/jira/browse/HBASE-25052
> Project: HBase
> Issue Type: Bug
> Components: metrics
> Affects Versions: 3.0.0-alpha-1, 2.3.0, 1.6.0, 2.2.3
> Reporter: Rushabh Shah
> Priority: Major
>
> FastLongHistogram#getCountAtOrBelow method is broken.
> If I revert HBASE-23245 then it works fine.
> Wrote a small test case in TestHistogramImpl.java :
> {code:java}
> @Test
> public void testAdd1() {
> HistogramImpl histogram = new HistogramImpl();
> for (int i = 0; i < 100; i++) {
> histogram.update(i);
> }
> Snapshot snapshot = histogram.snapshot();
> // This should return count as 6 since we added 0, 1, 2, 3, 4, 5
> Assert.assertEquals(6, snapshot.getCountAtOrBelow(5));
> {code}
> It fails as below:
> java.lang.AssertionError:
> Expected :6
> Actual :100
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