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https://issues.apache.org/jira/browse/HBASE-24389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17118596#comment-17118596
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Duo Zhang commented on HBASE-24389:
-----------------------------------
The patch aims to provide rpc methods for looking up meta region locations from
root table, and also change the client to make use the new API to locate meta,
instead of going to the old ConnectionRegistry interface.
In general, I think we could move this method to the ClientMetaService but I do
not think we should lookup this in Registry. As in our deployment, we have
observer nodes for zk so we do not want to use the MasterRegistry, but we still
want to spread the loads of accessing root table across multiple servers.
In this patch, all the logic for accessing root table at client side is in
AsyncMetaTableRegionLocator, so it is easy to make the actually accessing code
pluggable in follow-on issues.
There are several UTs which aim to test cluster without active
master(especially the region replicas related UTs, not sure why), the current
solution is to cache the locations of meta regions so we do not go to master
when performing get/put. This can be changed after we introduce something like
the MasterRegistry so client could go to standby masters to ask for the
location for meta.
TestMetaWithReplicas.testShutdownHandling is disabled for now, it has the same
problem with the above UTs and is not easy to find a way to cache the
locations. Will try to enable it in the future.
Thanks.
> Introduce a new master rpc service to locate meta region through root region
> ----------------------------------------------------------------------------
>
> Key: HBASE-24389
> URL: https://issues.apache.org/jira/browse/HBASE-24389
> Project: HBase
> Issue Type: Sub-task
> Components: master, meta
> Reporter: Duo Zhang
> Assignee: Duo Zhang
> Priority: Major
>
> And also reimlement the client logic to use the new api to locate meta
> region. In general, this will remove the assumption at client side that there
> is only one meta region.
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