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From Apache Wiki <wikidi...@apache.org>
Subject [Lucene-hadoop Wiki] Update of "Hbase/HbaseArchitecture" by udanax
Date Mon, 05 Feb 2007 07:35:53 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Lucene-hadoop Wiki" for change notification.

The following page has been changed by udanax:
http://wiki.apache.org/lucene-hadoop/Hbase/HbaseArchitecture

------------------------------------------------------------------------------
  
   * Immutable (write-once)
   * Sorted list of key/value pairs.
-  * '''Row/column space can be sparse.'''
+  * '''each Row/column space can be sparse.'''
   * Sequence of 64KB blocks
   * Block index __consists of the start keys for each block__
   * Compression
@@ -130, +130 @@

  As a first approximation, a Hadoop !MapFile satisfies these requirements. It is a persistent
(lives in the Hadoop DFS), ordered (!MapFile is based on !SequenceFile which is strictly ordered),
immutable (once written, an attempt to open a !MapFile for writing will overwrite the existing
contents) map from keys to values.
  
  Keys and values can be arbitrary byte strings.
+ '''and the system allows each row/column cell to store not just a single value but a set
of values with associated timestamps, simplifying analyses that examine how values have changed
over time.'''
  
  Given a key, you can find its value(s). It is possible to iterate over the entire file or
find a key and iterate from tha point forward.
  

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