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From "Yu Li (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-18388) Fix description on region page, explaining what a region name is made of
Date Mon, 17 Jul 2017 02:46:01 GMT

    [ https://issues.apache.org/jira/browse/HBASE-18388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16089247#comment-16089247

Yu Li commented on HBASE-18388:

Nice catch and good suggestions. Mind uploading a patch? [~larsgeorge]

[~misty] FYI sir.

> Fix description on region page, explaining what a region name is made of
> ------------------------------------------------------------------------
>                 Key: HBASE-18388
>                 URL: https://issues.apache.org/jira/browse/HBASE-18388
>             Project: HBase
>          Issue Type: Improvement
>          Components: master, regionserver, UI
>    Affects Versions: 1.3.1, 2.0.0-alpha-1
>            Reporter: Lars George
>            Priority: Minor
>              Labels: beginner
> In the {{RegionListTmpl.jamon}} we have this:
> {code}
>     <p>Region names are made of the containing table's name, a comma,
>     the start key, a comma, and a randomly generated region id.  To illustrate,
>     the region named
>     <em>domains,apache.org,5464829424211263407</em> is party to the table
>     <em>domains</em>, has an id of <em>5464829424211263407</em>
and the first key
>     in the region is <em>apache.org</em>.    The <em>hbase:meta</em>
'table' is an internal
>     system table (or a 'catalog' table in db-speak).
>     The hbase:meta table keeps a list of all regions in the system. The empty key is
used to denote
>     table start and table end.  A region with an empty start key is the first region
in a table.
>     If a region has both an empty start key and an empty end key, it's the only region
in the
>     table. See <a href="http://hbase.org">HBase Home</a> for further explication.<p>
> {code}
> This is wrong and worded oddly. What needs to be fixed facts wise is:
> - Region names contain (separated by commas) the full table name (including the namespace),
the start key, the time the region was created, and finally a dot with an MD5 hash of everything
before the dot. For example: {{test,,1499410125885.1544f69aeaf787755caa11d3567a9621.}}
> - The trailing dot is to distinguish legacy region names (like those used by the {{hbase:meta}}
> - The MD5 hash is used as the directory name within the HBase storage directories
> - The names for the meta table use a Jenkins hash instead, also leaving out the trailing
dot, for example {{hbase:meta,,1.1588230740}}. The time is always set to {{1}}.
> - The start key is printed in safe characters, escaping unprintable characters
> - The link to the HBase home page to explain more is useless and should be removed.
> - Also, for region replicas, the replica ID is inserted into the name, like so {{replicatable,,1486289678486_0001.3e8b7655299b21b3038ff8d39062467f.}},
see the {{_0001}} part.
> As for the wording, I would just make this all flow a little better, that "is party of"
sounds weird to me (IMHO).

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