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https://issues.apache.org/jira/browse/HBASE-24609?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17213511#comment-17213511
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Michael Stack commented on HBASE-24609:
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bq. The plan is to move it to hbase-server...
Is this plan written down anywhere?
bq. ....but the balancer class will write to meta table(surprise ha?) so we
have to keep it in hbase-balancer, as hbase-server depends on hbase-balancer.
It does? Thats weird. I'd think it shouldn't. Can we fix it? Maybe balancer is
in wrong place in the dependency hierarchy then?
MTA was in hbase-client though? That a better place than 'balancer'?
bq. The idea is that, now only master can modify meta....
Yes. Good.
bq. ....ClientMetaTableAccessor we only have read methods ....
Class javadoc says it reads and writes.
bq. And on the question about when to use ClientMTA and when MTA, the answer
is, do not use them both if possible.
Add this to javadoc on the two classes?
bq. Providing a utility class to modify meta is not a good idea. ?
?
MTA was one-way of getting to meta table. Now we have a client way and the MTA
to write and we also have the new utility CatalogFamilyFormat.... And I see
the RegionStateStore is getting some extra responsibility.
bq. At client side, use RegionLocator and methods in Admin as much as possible.
At master side, use RegionStateStore to update meta, use AssignmentManager to
get the state of a region, use TableStateManager to get the state of table. At
region server side, avoid touching meta directly as much as possible, as the
ClusterConnection will do the work for you.
Nothing wrong w/ the above. RSS was using the MTA. Sounds like you want to move
MTA into RSS?
bq. The class is as its name, only provide utility methods for the data format
of the 'info' column, which we describe as 'Catalog'.
Is this explicit anywhere ? That it is only 'info' ? And is it explicit that
'info' column is 'catalog'? (I thought catalog a generic term for 'system'
tables).
What about the comment on CatalogFamilyFormat? This class seems to be doing
what MTA was doing, what you seem to be trying to undo. Its name is odd too.
Thanks.
> Move MetaTableAccessor out of hbase-client
> ------------------------------------------
>
> Key: HBASE-24609
> URL: https://issues.apache.org/jira/browse/HBASE-24609
> Project: HBase
> Issue Type: Task
> Components: amv2, Client, meta
> Reporter: Duo Zhang
> Assignee: Duo Zhang
> Priority: Major
> Fix For: 3.0.0-alpha-1
>
>
> On master branch we have AsyncMetaTableAccessor which is used at client side
> and MetaTableAccessor has lots of internal methods for implementing
> assignment, which is not part of our client code.
> So let's move it to hbase-server, and in the future, maybe in hbase-balancer?
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