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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hbase/HbaseArchitecture" by MatthewHawthorne
Date Wed, 21 May 2008 10:33:24 GMT
Dear Wiki user,

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

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

The comment on the change is:
Fixed Javadoc links.

------------------------------------------------------------------------------
  [[Anchor(client)]]
  = Client API =
  
- See the Javadoc for [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HTable.html
HTable] and [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HBaseAdmin.html
HBaseAdmin]
+ See the Javadoc for [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HTable.html
HTable] and [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HBaseAdmin.html
HBaseAdmin]
  
  
  [[Anchor(scanner)]]
  == Scanner API ==
  
- To obtain a scanner, a Cursor-like row 'iterator' that must be closed, [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HTable.html#HTable(org.apache.hadoop.conf.Configuration,%20org.apache.hadoop.io.Text)
instantiate an HTable], and then invoke ''obtainScanner''.  This method returns an [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HScannerInterface.html
HScannerInterface] against which you call [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HScannerInterface.html#next(org.apache.hadoop.hbase.HStoreKey,%20java.util.SortedMap)
next] and ultimately [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HScannerInterface.html#close()
close].
+ To obtain a scanner, a Cursor-like row 'iterator' that must be closed, [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HTable.html#HTable(org.apache.hadoop.conf.Configuration,%20org.apache.hadoop.io.Text)
instantiate an HTable], and then invoke ''obtainScanner''.  This method returns an [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HScannerInterface.html
HScannerInterface] against which you call [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HScannerInterface.html#next(org.apache.hadoop.hbase.HStoreKey,%20java.util.SortedMap)
next] and ultimately [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HScannerInterface.html#close()
close].
  
  [[Anchor(hregion)]]
  = HRegion (Tablet) Server =
@@ -342, +342 @@

  Consequently each row in the META and ROOT tables has three members of
  the "info:" column family:
  
-  1. '''info:regioninfo''' contains a serialized [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HRegionInfo.html
HRegionInfo object]
+  1. '''info:regioninfo''' contains a serialized [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HRegionInfo.html
HRegionInfo object]
-  1. '''info:server''' contains a serialized string which is the output from [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HServerAddress.html#toString()
HServerAddress.toString()]. This string can be supplied to one of the [http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/hbase/HServerAddress.html#HServerAddress(java.lang.String)
HServerAddress constructors].
+  1. '''info:server''' contains a serialized string which is the output from [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HServerAddress.html#toString()
HServerAddress.toString()]. This string can be supplied to one of the [http://hadoop.apache.org/hbase/docs/current/org/apache/hadoop/hbase/HServerAddress.html#HServerAddress(java.lang.String)
HServerAddress constructors].
   1. '''info:startcode''' a serialized long integer generated by the H!RegionServer when
it starts. The H!RegionServer sends this start code to the master so the master can determine
if the server information in the META and ROOT regions is stale.
  
  Thus, a client does not need to contact the HMaster after it learns

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