[jira] [Commented] (HBASE-3171) Drop ROOT and instead store META location(s) directly in ZooKeeper

["Devaraj Das (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-3171?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13537657#comment-13537657 ] 

Devaraj Das commented on HBASE-3171:
------------------------------------

Hey [~jdcryans], are you planning to do all the above in a single patch. Can we break this up into multiple parts (like the migration code, etc.). Since this patch somewhat blocks HBASE-7213, I was wondering whether we could commit the core functionality (the patch you attached here), and do the rest as follow ups. After the core patch goes in (including the unit test fixes), we could commit 7213.. Thoughts?

bq. Next up is trying to figure out what to do with MetaNodeTracker and metaAvailable in CatalogTracker, it seems we could do without them?

Looking at the patch, I see that you have commented out lots of code, including stuff to do with metaAvailable. In that sense, seems we could do without them..
                
> Drop ROOT and instead store META location(s) directly in ZooKeeper
> ------------------------------------------------------------------
>
>                 Key: HBASE-3171
>                 URL: https://issues.apache.org/jira/browse/HBASE-3171
>             Project: HBase
>          Issue Type: Improvement
>          Components: Client, master, regionserver, Zookeeper
>            Reporter: Jonathan Gray
>         Attachments: HBASE-3171.patch, HBASE-3171-v2.patch
>
>
> Rather than storing the ROOT region location in ZooKeeper, going to ROOT, and reading the META location, we should just store the META location directly in ZooKeeper.
> The purpose of the root region from the bigtable paper was to support multiple meta regions.  Currently, we explicitly only support a single meta region, so the translation from our current code of a single root location to a single meta location will be very simple.  Long-term, it seems reasonable that we could store several meta region locations in ZK.  There's been some discussion in HBASE-1755 about actually moving META into ZK, but I think this jira is a good step towards taking some of the complexity out of how we have to deal with catalog tables everywhere.
> As-is, a new client already requires ZK to get the root location, so this would not change those requirements in any way.
> The primary motivation for this is to simplify things like CatalogTracker.  The way we can handle root in that class is really simple but the tracking of meta is difficulty and a bit hacky.  This hack on tracking of the meta location is what caused one of the bugs over in HBASE-3159.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira