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https://issues.apache.org/jira/browse/HBASE-21991?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16788429#comment-16788429
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Xu Cang edited comment on HBASE-21991 at 3/9/19 1:27 AM:
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very good analysis! And the patch looks great. [~jatsakthi]
I only have some minor code comments below:
For the unit test,
{code:java}
"try{
connection = UTIL.getConnection();"
{code}
Please do try-with-resource approach.
{code:java}
"e.printStackTrace();"
{code}
Can you log the exception?
Also, is that possible to count rows you wrote after all the Put-s done as part
of this test?
was (Author: xucang):
very good analysis! And the patch looks great. [~jatsakthi]
I only have some minor code comments below:
For the unit test,
{code:java}
"try{
connection = UTIL.getConnection();"
{code}
Please do try-with-resource approach.
"e.printStackTrace();" Can you log the exception?
Also, is that possible to count rows you wrote after all the Put-s done as part
of this test?
> Fix MetaMetrics issues - [Race condition, Faulty remove logic], few
> improvements
> --------------------------------------------------------------------------------
>
> Key: HBASE-21991
> URL: https://issues.apache.org/jira/browse/HBASE-21991
> Project: HBase
> Issue Type: Bug
> Components: Coprocessors, metrics
> Reporter: Sakthi
> Assignee: Sakthi
> Priority: Major
> Attachments: hbase-21991.master.001.patch,
> hbase-21991.master.002.patch
>
>
> Here is a list of the issues related to the MetaMetrics implementation:
> +*Bugs*+:
> # [_Lossy counting for top-k_] *Faulty remove logic of non-eligible meters*:
> Under certain conditions, we might end up storing/exposing all the meters
> rather than top-k-ish
> # MetaMetrics can throw NPE resulting in aborting of the RS because of a
> *Race Condition*.
> +*Improvements*+:
> # With high number of regions in the cluster, exposure of metrics for each
> region blows up the JMX from ~140 Kbs to 100+ Mbs depending on the number of
> regions. It's better to use *lossy counting to maintain top-k for region
> metrics* as well.
> # As the lossy meters do not represent actual counts, I think, it'll be
> better to *rename the meters to include "lossy" in the name*. It would be
> more informative while monitoring the metrics and there would be less
> confusion regarding actual counts to lossy counts.
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