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https://issues.apache.org/jira/browse/HBASE-15518?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15207035#comment-15207035
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Elliott Clark commented on HBASE-15518:
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They were removed explicitly because they give very skewed numbers based on how
many regions are on each region server. If one regionserver has 10 regions of a
table and another has 5 then the numbers become almost nonsensical. You then
need to normalize them per number of regions and you're back at a per region
metrics. If a user is interested in per table across the whole cluster then
aggregating the region metrics is the best way. If they are looking for a
certain region server then not aggregating is the correct thing.
On top of all that the other reason they were removed is because it caused a
whole lot of contention for the debatable gains. Per region metrics are much
less contented so adding them is lower cost. Per server metrics are contended
so we should only add the minimum set of metrics needed there.
> Add Per-Table metrics back
> --------------------------
>
> Key: HBASE-15518
> URL: https://issues.apache.org/jira/browse/HBASE-15518
> Project: HBase
> Issue Type: Sub-task
> Reporter: Enis Soztutar
> Assignee: Alicia Ying Shu
> Fix For: 2.0.0, 1.4.0
>
>
> We used to have per-table metrics, but it was removed in some restructuring.
> We have per-region metrics, and per-regionserver metrics, but nothing in
> between.
> For majority of users, per-region is too granular, they are mostly interested
> in table level aggregates. This is especially useful in multi-tenant cases
> where a table's disk usage, number of requests, etc can be made much more
> visible.
> In this jira, we'll add the basic infrastructure to add a single (or a few)
> per-table metrics. Than we can improve on that by adding remaining metrics
> from the region server level.
> The plan is to NOT aggregate per-table metrics at master for now. Just
> aggregation of per-region metrics at the per-table level for every
> regionserver.
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