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Posted to commits@hbase.apache.org by st...@apache.org on 2011/08/24 08:54:38 UTC
svn commit: r1160988 - in /hbase/trunk: CHANGES.txt src/docbkx/book.xml
Author: stack
Date: Wed Aug 24 06:54:38 2011
New Revision: 1160988
URL: http://svn.apache.org/viewvc?rev=1160988&view=rev
Log:
HBASE-4242 Add documentation for HBASE-4071
Modified:
hbase/trunk/CHANGES.txt
hbase/trunk/src/docbkx/book.xml
Modified: hbase/trunk/CHANGES.txt
URL: http://svn.apache.org/viewvc/hbase/trunk/CHANGES.txt?rev=1160988&r1=1160987&r2=1160988&view=diff
==============================================================================
--- hbase/trunk/CHANGES.txt (original)
+++ hbase/trunk/CHANGES.txt Wed Aug 24 06:54:38 2011
@@ -456,6 +456,7 @@ Release 0.91.0 - Unreleased
(todd)
HBASE-4071 Data GC: Remove all versions > TTL EXCEPT the last
written version (Lars Hofhansl)
+ HBASE-4242 Add documentation for HBASE-4071 (Lars Hofhansl)
Release 0.90.5 - Unreleased
Modified: hbase/trunk/src/docbkx/book.xml
URL: http://svn.apache.org/viewvc/hbase/trunk/src/docbkx/book.xml?rev=1160988&r1=1160987&r2=1160988&view=diff
==============================================================================
--- hbase/trunk/src/docbkx/book.xml (original)
+++ hbase/trunk/src/docbkx/book.xml Wed Aug 24 06:54:38 2011
@@ -263,6 +263,21 @@ admin.enableTable(table);
compactions. The number of versions may need to be increased or decreased depending on application needs.
</para>
</section>
+ <section xml:id="schema.minversions">
+ <title>
+ Minimum Number of Versions
+ </title>
+ <para>Like number of row versions, the minimum number of row versions to keep is configured per column
+ family via <link xlink:href="http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/HColumnDescriptor.html">HColumnDescriptor</link>.
+ The default is 0, which means the feature is disabled.
+ The minimum number of row versions parameter is used together with the time-to-live parameter and can be combined with the
+ number of row versions parameter to allow configurations such as
+ "keep the last T minutes worth of data, at most N versions, <emphasis>but keep at least M versions around</emphasis>"
+ (where M is the value for minimum number of row versions, M<=N).
+ This parameter should only be set when time-to-live is enabled for a column family and must be less or equal to the
+ number of row versions.
+ </para>
+ </section>
<section xml:id="changing.rowkeys">
<title>
Immutability of Rowkeys