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https://issues.apache.org/jira/browse/HBASE-24389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17119187#comment-17119187
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Duo Zhang commented on HBASE-24389:
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{quote}
We already have client-side Interfaces – Registry or RegionLocator. Discussion
of why these put aside?
{quote}
I'v replied why I do not want to add this to the Registry above, and for
RegionLocator, it is still there and is also used for locating meta. I've also
relied at other places as well, on the PR and also on the design doc. PTAL.
{quote}
I hear the bit about not wanting to expose an API that would be hard to
implement in different contexts but the new API is not how we do location query
up to this. New API seems to dictate a Region-at-a-time; will this work if the
RootTable has your 10k entries? What you thinking?
{quote}
I do not get your point sir, the new API is for dealing with 10k entries in
root table. We always locate a region at a time in the client code, I do not
think it is a good idea to always fetch 10k entries everytime when you only
need one of them? Other things such as prefetching and caching are controlled
by the locator related classes. We have a getAllMetaRegionLocations method, you
are free to call this method in background to pull all the entries to client,
but I do not think this is necessary. In our largest cluster which has about
20k regions, there are thousands of tables but usually a user will only contact
to a small set of tables, and typically under the same namespace, which means,
they will only need to access a single meta region.
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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