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Posted to commits@hbase.apache.org by mi...@apache.org on 2014/09/16 05:03:10 UTC
git commit: HBASE-10950 Document global configuration for maxVersion
Repository: hbase
Updated Branches:
refs/heads/master 555469287 -> a86d4dbfe
HBASE-10950 Document global configuration for maxVersion
Project: http://git-wip-us.apache.org/repos/asf/hbase/repo
Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/a86d4dbf
Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/a86d4dbf
Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/a86d4dbf
Branch: refs/heads/master
Commit: a86d4dbfe9030346fef2aefceec1de7420bceba2
Parents: 5554692
Author: Misty Stanley-Jones <ms...@cloudera.com>
Authored: Tue Sep 16 13:02:21 2014 +1000
Committer: Misty Stanley-Jones <ms...@cloudera.com>
Committed: Tue Sep 16 13:02:21 2014 +1000
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src/main/docbkx/book.xml | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
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http://git-wip-us.apache.org/repos/asf/hbase/blob/a86d4dbf/src/main/docbkx/book.xml
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diff --git a/src/main/docbkx/book.xml b/src/main/docbkx/book.xml
index 00c5041..01c6b41 100644
--- a/src/main/docbkx/book.xml
+++ b/src/main/docbkx/book.xml
@@ -660,6 +660,37 @@ try {
<emphasis>Overwriting values at existing timestamps</emphasis> mentioned in the
article no longer holds in HBase. This section is basically a synopsis of this article
by Bruno Dumon.</para>
+
+ <section xml:id="specify.number.of.versions">
+ <title>Specifying the Number of Versions to Store</title>
+ <para>The maximum number of versions to store for a given column is part of the column
+ schema and is specified at table creation, or via an <command>alter</command> command, via
+ <code>HColumnDescriptor.DEFAULT_VERSIONS</code>. Prior to HBase 0.96, the default number
+ of versions kept was <literal>3</literal>, but in 0.96 and newer has been changed to
+ <literal>1</literal>.</para>
+ <example>
+ <title>Modify the Maximum Number of Versions for a Column</title>
+ <para>This example uses HBase Shell to keep a maximum of 5 versions of column
+ <code>f1</code>. You could also use <link
+ xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/HColumnDescriptor.html"
+ >HColumnDescriptor</link>.</para>
+ <screen><![CDATA[hbase> alter ‘t1′, NAME => ‘f1′, VERSIONS => 5]]></screen>
+ </example>
+ <example>
+ <title>Modify the Minimum Number of Versions for a Column</title>
+ <para>You can also specify the minimum number of versions to store. By default, this is
+ set to 0, which means the feature is disabled. The following example sets the minimum
+ number of versions on field <code>f1</code> to <literal>2</literal>, via HBase Shell.
+ You could also use <link
+ xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/HColumnDescriptor.html"
+ >HColumnDescriptor</link>.</para>
+ <screen><![CDATA[hbase> alter ‘t1′, NAME => ‘f1′, MIN_VERSIONS => 2]]></screen>
+ </example>
+ <para>Starting with HBase 0.98.2, you can specify a global default for the maximum number of
+ versions kept for all newly-created columns, by setting
+ <option>hbase.column.max.version</option> in <filename>hbase-site.xml</filename>. See
+ <xref linkend="hbase.column.max.version"/>.</para>
+ </section>
<section
xml:id="versions.ops">