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From "stack (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HBASE-451) Remove HTableDescriptor from HRegionInfo
Date Wed, 18 Jun 2008 22:47:45 GMT

    [ https://issues.apache.org/jira/browse/HBASE-451?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12606123#action_12606123
] 

stack commented on HBASE-451:
-----------------------------

Thinking more on this -- prompted by the J-D comment above -- I agree that a hbase.rootdir/TABLEDIR/schema
file -- is the way to go rather than a new catalog table.  The file will be read rarely --
during the onlining/deploy of a region.  The table schema file could be stored in ZK but having
our schema in multiple places -- in HDFS and in ZK -- makes me queasy.   The JK point above
that if it were in the TABLEDIR directory, an offline hbasck repair tool would also have access,
is a strong argument for keeping it in hdfs.

> Remove HTableDescriptor from HRegionInfo
> ----------------------------------------
>
>                 Key: HBASE-451
>                 URL: https://issues.apache.org/jira/browse/HBASE-451
>             Project: Hadoop HBase
>          Issue Type: Improvement
>          Components: master, regionserver
>    Affects Versions: 0.2.0
>            Reporter: Jim Kellerman
>
> There is an HRegionInfo for every region in HBase. Currently HRegionInfo also contains
the HTableDescriptor (the schema). That means we store the schema n times where n is the number
of regions in the table.
> Additionally, for every region of the same table that the region server has open, there
is a copy of the schema. Thus it is stored in memory once for each open region.
> If HRegionInfo merely contained the table name the HTableDescriptor could be stored in
a separate file and easily found.

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