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https://issues.apache.org/jira/browse/HBASE-7958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13603908#comment-13603908
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Jeff Whiting commented on HBASE-7958:
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[~jesse_yates] I understand the concern and agree that we don't want to
reinvent the wheel.
Although it seems like some basic stats would be extremely useful. For example
the region balancer could find the hottest regions (ones with the more requests
per second) and automatically balance them across different region servers. A
region could be split because it is too hot to reduce the number of requests
rather than only splitting on size.
Systems like ganglia / opentsb typically do really well at giving high level
stats at a server level. However they would do poorly if they tried to have
stats on every region (we have over 1000 regions and it would be a mess).
Finally we could have some pretty graphs on the HMaster similar to Accumulo
(see:
http://i1-scripts.softpedia-static.com/screenshots/Apache-Accumulo_1.png?1341920105)
> Statistics per-column family per-region
> ---------------------------------------
>
> Key: HBASE-7958
> URL: https://issues.apache.org/jira/browse/HBASE-7958
> Project: HBase
> Issue Type: New Feature
> Affects Versions: 0.96.0
> Reporter: Jesse Yates
> Assignee: Jesse Yates
> Fix For: 0.96.0
>
> Attachments: hbase-7958_rough-cut-v0.patch,
> hbase-7958-v0-parent.patch, hbase-7958-v0.patch
>
>
> Originating from this discussion on the dev list:
> http://search-hadoop.com/m/coDKU1urovS/Simple+stastics+per+region/v=plain
> Essentially, we should have built-in statistics gathering for HBase tables.
> This allows clients to have a better understanding of the distribution of
> keys within a table and a given region. We could also surface this
> information via the UI.
> There are a couple different proposals from the email, the overview is this:
> We add in something on compactions that gathers stats about the keys that are
> written and then we surface them to a table.
> The possible proposals include:
> *How to implement it?*
> # Coprocessors -
> ** advantage - it easily plugs in and people could pretty easily add their
> own statistics.
> ** disadvantage - UI elements would also require this, we get into dependent
> loading, which leads down the OSGi path. Also, these CPs need to be installed
> _after_ all the other CPs on compaction to ensure they see exactly what gets
> written (doable, but a pain)
> # Built into HBase as a custom scanner
> ** advantage - always goes in the right place and no need to muck about with
> loading CPs etc.
> ** disadvantage - less pluggable, at least for the initial cut
> *Where do we store data?*
> # .META.
> ** advantage - its an existing table, so we can jam it into another CF there
> ** disadvantage - this would make META much larger, possibly leading to
> splits AND will make it much harder for other processes to read the info
> # A new stats table
> ** advantage - cleanly separates out the information from META
> ** disadvantage - should use a 'system table' idea to prevent accidental
> deletion, manipulation by arbitrary clients, but still allow clients to read
> it.
> Once we have this framework, we can then move to an actual implementation of
> various statistics.
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