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The following page has been changed by stack: http://wiki.apache.org/lucene-hadoop/Hbase/HbaseArchitecture The comment on the change is: Move News from here to HBase home page ------------------------------------------------------------------------------ This effort is still a "work in progress". Please feel free to add comments, but please make them stand out by bolding or underlining them. Thanks! - - '''NEWS:''' (updated 2007/05/30) - 1. HBase is being updated frequently. The latest code can always be found in the [http://svn.apache.org/viewvc/lucene/hadoop/trunk/src/contrib/hbase/ trunk of the Hadoop svn tree]. - 1. HBase now has its own component in the [https://issues.apache.org/jira/browse/HADOOP Hadoop Jira]. Bug reports, contributions, etc. should be tagged with the component '''contrib/hbase'''. - 1. It is now possible to add or delete column families after a table exists. Before either of these operations the table being updated must be taken off-line (disabled). - 1. Data compression is available on a per-column family basis. The options are: - * no compression - * record level compression - * block level compression = Table of Contents = @@ -74, +65 @@ ||<^|5> "com.cnn.www" ||<:> t9 || ||<)> "anchor:cnnsi.com" ||<:> "CNN" || || ||<:> t8 || ||<)> "anchor:my.look.ca" ||<:> "CNN.com" || || ||<:> t6 ||<:> "<html>..." || || ||<:> "text/html" || - ||<:> t5 ||<:> `"<html>..."` || || || || + ||<:> t5 ||<:> "<html>..." || || || || - ||<:> t3 ||<:> `"<html>..."` || || || || + ||<:> t3 ||<:> "<html>..." || || || || [[Anchor(physical)]] == Physical Storage View == @@ -90, +81 @@ ||<:> '''Row Key''' ||<:> '''Time Stamp''' ||<:> '''Column''' ''"contents:"'' || ||<^|3> "com.cnn.www" ||<:> t6 ||<:> "<html>..." || - ||<:> t5 ||<:> `"<html>..."` || + ||<:> t5 ||<:> "<html>..." || - ||<:> t3 ||<:> `"<html>..."` || + ||<:> t3 ||<:> "<html>..." || [[BR]] @@ -174, +165 @@ [[Anchor(scanner)]] == Scanner API == - To obtain a scanner, [http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Nightly/javadoc/org/apache/hadoop/hbase/HClient.html#openTable(org.apache.hadoop.io.Text) open the table], and use [http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Nightly/javadoc/org/apache/hadoop/hbase/HClient.html#obtainScanner(org.apache.hadoop.io.Text%5B%5D,%20org.apache.hadoop.io.Text) obtainScanner]. + To obtain a scanner, a 'iterator' that must be closed, [http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Nightly/javadoc/org/apache/hadoop/hbase/HClient.html#openTable(org.apache.hadoop.io.Text) open the table], and use [http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Nightly/javadoc/org/apache/hadoop/hbase/HClient.html#obtainScanner(org.apache.hadoop.io.Text%5B%5D,%20org.apache.hadoop.io.Text) obtainScanner]. Then use the [http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Nightly/javadoc/org/apache/hadoop/hbase/HScannerInterface.html scanner API] @@ -185, +176 @@ key. Physically, tables are broken into HRegions. An HRegion is identified by its tablename plus a start/end-key pair. A given HRegion with keys <start> and <end> will store all the rows from (<start>, - <end>]. A set of HRegions, sorted appropriately, forms an entire + <end>). A set of HRegions, sorted appropriately, forms an entire table. All data is physically stored using Hadoop's DFS. Data is served to
