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https://issues.apache.org/jira/browse/HBASE-8410?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13943402#comment-13943402
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Andrew Purtell commented on HBASE-8410:
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bq. We are trying to stop users who might be running applications which might
be accidentally creating large number of tables or regions.
Understood. It would be good to reconsider if you really need something running
in the regionserver though. Installing a RegionObserver adds a certain (small)
cost to every op even though you are only sitting on a pre split hook.
Rejecting splits in a pre split hook is messy as mentioned above because you
are not changing the higher level decisionmaking on whether to split or not in
the first place. Coordinating between multiple processes on the cluster
requires either meta scanning or the ZK mediated cache, which could be avoided
if there is a single arbiter running in the master.
bq. ... accidentally creating large number of tables ///
Can be handled in the master by intercepting table create requests in the
namespace
bq. .. accidentally creating large number of [...] regions ...
On the Master manage RegionSplitPolicy details in the schema such that the
user/application cannot override the settings. For example, when through
polling you discover a table is at or just slightly over a high water mark,
disable region splits by setting “hbase.hregion.max.filesize” in the table
schema to the maximum value and set the split policy in the schema to
ConstantSizeRegionSplitPolicy.
What this won't cover is interception of administrative split requests made
directly to the regionserver. However you could still handle this in the master
by watching for when the number of regions for a table is at or over a hard
limit. Respond by offlining the table. A regionserver won't process a split
request for a region it is not serving. This achieves the objective of stopping
a runaway user or application.
> Basic quota support for namespaces
> ----------------------------------
>
> Key: HBASE-8410
> URL: https://issues.apache.org/jira/browse/HBASE-8410
> Project: HBase
> Issue Type: Sub-task
> Reporter: Francis Liu
> Assignee: Vandana Ayyalasomayajula
> Attachments: HBASE-8410.docx, HBASE-8410_trunk_10.patch,
> HBASE-8410_trunk_10.patch, HBASE-8410_trunk_11.patch,
> HBASE-8410_trunk_12.patch, HBASE-8410_trunk_13.patch,
> HBASE-8410_trunk_14.patch, HBASE-8410_trunk_15.patch,
> HBASE-8410_trunk_2.patch, HBASE-8410_trunk_3.patch, HBASE-8410_trunk_4.patch,
> HBASE-8410_trunk_4.patch, HBASE-8410_trunk_5.patch, HBASE-8410_trunk_6.patch,
> HBASE-8410_trunk_7.patch, HBASE-8410_trunk_8.patch, HBASE-8410_trunk_9.patch,
> HBASE_8410.patch, HBASE_8410_1_trunk.patch
>
>
> This task involves creating an observer which provides basic quota support to
> namespaces in terms of (1) number of tables and (2) number of regions. The
> quota support can be enabled by setting:
> <property>
> <name>hbase.coprocessor.region.classes</name>
> <value>org.apache.hadoop.hbase.namespace.NamespaceController</value>
> </property>
> <property>
> <name>hbase.coprocessor.master.classes</name>
> <value>org.apache.hadoop.hbase.namespace.NamespaceController</value>
> </property>
> in the hbase-site.xml.
> To add quotas to namespace, while creating namespace properties need to be
> added.
> Examples:
> 1. namespace_create 'ns1', {'hbase.namespace.quota.maxregion'=>'10'}
> 2. 1. namespace_create 'ns2', {'hbase.namespace.quota.maxtables'=>'2'},
> {'hbase.namespace.quota.maxregion'=>'5'}
> The quotas can be modified/added to namespace at any point of time.
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