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From: Apache Wiki <wikidiffs@apache.org>
To: core-commits@hadoop.apache.org
Date: Thu, 02 Apr 2009 22:07:05 -0000
Message-ID: <20090402220705.25411.51023@aurora.apache.org>
Subject: [Hadoop Wiki] Trivial Update of "Hbase/DesignOverview" by
 EvgenyRyabitskiy

Dear Wiki user,

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The following page has been changed by EvgenyRyabitskiy:
http://wiki.apache.org/hadoop/Hbase/DesignOverview

------------------------------------------------------------------------------
    * [#conceptual Conceptual View]
    * [#physical Physical Storage View]
     * [#regions Regions(Rowranges)]
+  * [#api API]
   * [#design Architecture Design]
    * [#master HBaseMaster]
    * [#hregionserv HRegionServer]
    * [#client HBase Client]
- 
+  * [#impl Implementation]
  [[Anchor(intro)]]
  = Introduction =
  
@@ -92, +93 @@

   * !StoreFiles maintain the sparse index in a separate file
   * HBase extends !StoreFiles so that a bloom filter can be employed to enhance negative lookup performance. The hash function employed is one developed by Bob Jenkins.
  
+ [[Anchor(api)]]
+ = API =
+ 
+ == Client API ==
+ 
+ See the Javadoc for [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HTable.html HTable] and [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HBaseAdmin.html HBaseAdmin]
+ 
+ == Scanner API ==
+ 
+ To obtain a scanner, a Cursor-like row 'iterator' that must be closed, [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#HTable(org.apache.hadoop.hbase.HBaseConfiguration,%20java.lang.String) instantiate an HTable], and then invoke ''getScanner''.  This method returns an [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Scanner.html Scanner] against which you call [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Scanner.html#next() next] and ultimately [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Scanner.html#close() close].
+ 
  [[Anchor(design)]]
  = Architecture Design =
  
@@ -212, +224 @@

  
  Should a region be reassigned either by the master for load balancing or because a region server has died, the client will rescan the META table to determine the new location of the user region. If the META region has been reassigned, the client will rescan the ROOT region to determine the new location of the META region. If the ROOT region has been reassigned, the client will contact the master to determine the new ROOT region location and will locate the user region by repeating the original process described above.
  
- === Client API ===
+ [[Anchor(impl)]]
+ = Implementation =
+ Here will be details of HBase implementation. 
  
- See the Javadoc for [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HTable.html HTable] and [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HBaseAdmin.html HBaseAdmin]
- 
- 
- ==== Scanner API ====
- 
- To obtain a scanner, a Cursor-like row 'iterator' that must be closed, [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#HTable(org.apache.hadoop.hbase.HBaseConfiguration,%20java.lang.String) instantiate an HTable], and then invoke ''getScanner''.  This method returns an [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Scanner.html Scanner] against which you call [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Scanner.html#next() next] and ultimately [http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/Scanner.html#close() close].
-