Details
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Improvement
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Status: Open
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Minor
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Resolution: Unresolved
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1.3.1, 2.0.0-alpha-1
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None
Description
In the RegionListTmpl.jamon we have this:
<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>
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 table)
- 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).