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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Trivial Update of "Hbase/DesignOverview" by EvgenyRyabitskiy
Date Thu, 02 Apr 2009 22:07:59 GMT
Dear Wiki user,

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The following page has been changed by EvgenyRyabitskiy:

   * [#datamodel Data Model]
    * [#conceptual Conceptual View]
    * [#physical Physical Storage View]
-    * [#regions Regions(Rowranges)]
   * [#api API]
   * [#design Architecture Design]
    * [#master HBaseMaster]
@@ -83, +82 @@

  However, if no timestamp is supplied, the most recent value for a particular column would
be returned and would also be the first one found since timestamps are stored in descending
order. Thus a request for the values of all columns in the row "com.cnn.www" if no timestamp
is specified would be: the value of ''"contents:"'' from time stamp t6, the value of ''"anchor:cnnsi.com"''
from time stamp t9, the value of ''"anchor:my.look.ca"'' from time stamp t8 and the value
of ''"mime:"'' from time stamp t6.
- [[Anchor(regions)]]
  === Regions (Row Ranges) ===
  To an application, a table appears to be a list of tuples sorted by row key ascending, column
name ascending and timestamp descending.  Physically, tables are broken up into row ranges
called ''regions''. Each row range contains rows from start-key (inclusive) to end-key (exclusive).
A set of regions, sorted appropriately, forms an entire table. Row range identified by the
table name and start-key.

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