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hbase-5380. book.xml, comment about KeyValue instances not being split across blocks 

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1242878 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Doug Meil 2012-02-10 18:27:42 +00:00
parent ac8ccdf477
commit 9d7d022ec6
1 changed files with 4 additions and 2 deletions
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src/docbkx/book.xml
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@ -2082,7 +2082,7 @@ myHtd.setValue(HTableDescriptor.SPLIT_POLICY, MyCustomSplitPolicy.class.getName(
<section xml:id="keyvalue"> <section xml:id="keyvalue">
<title>KeyValue</title> <title>KeyValue</title>
<para>The KeyValue class is the heart of data storage in HBase. KeyValue wraps a byte array and takes offsets and lengths into passed array <para>The KeyValue class is the heart of data storage in HBase. KeyValue wraps a byte array and takes offsets and lengths into passed array
at where to start interpreting the content as KeyValue. at where to start interpreting the content as KeyValue.
</para> </para>
<para>The KeyValue format inside a byte array is: <para>The KeyValue format inside a byte array is:
<itemizedlist> <itemizedlist>
@ -2103,7 +2103,9 @@ myHtd.setValue(HTableDescriptor.SPLIT_POLICY, MyCustomSplitPolicy.class.getName(
<listitem>keytype (e.g., Put, Delete, DeleteColumn, DeleteFamily)</listitem> <listitem>keytype (e.g., Put, Delete, DeleteColumn, DeleteFamily)</listitem>
</itemizedlist> </itemizedlist>
</para> </para>
<para>For more information, see the <link xlink:href="http://hbase.apache.org/xref/org/apache/hadoop/hbase/KeyValue.html">KeyValue source code</link>. <para>KeyValue instances are <emphasis>not</emphasis> split across blocks.
For example, if there is an 8 MB KeyValue, even if the block-size is 64kb this KeyValue will be read
in as a coherent block. For more information, see the <link xlink:href="http://hbase.apache.org/xref/org/apache/hadoop/hbase/KeyValue.html">KeyValue source code</link>.
</para> </para>
<section xml:id="keyvalue.example"><title>Example</title> <section xml:id="keyvalue.example"><title>Example</title>
<para>To emphasize the points above, examine what happens with two Puts for two different columns for the same row:</para> <para>To emphasize the points above, examine what happens with two Puts for two different columns for the same row:</para>