HBASE-3883 book.xml / added something in schema design and FAQ about not being able to change rowkeys

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1125470 13f79535-47bb-0310-9956-ffa450edef68

src/docbkx/book.xml

@@ -217,6 +217,15 @@ throws InterruptedException, IOException {
       compactions.  The number of versions may need to be increased or decreased depending on application needs.
   </para>
   </section>
+  <section xml:id="changing.rowkeys">
+  <title>
+  Immutability of Rowkeys
+  </title>
+  <para>Rowkeys cannot be changed.  The only way they can be "changed" in a table is if the row is deleted and then re-inserted.
+  This is a fairly common question on the HBase dist-list so it pays to get the rowkeys right the first time (and/or before you've 
+  inserted a lot of data).
+  </para>
+  </section>
 
   </chapter>
 
@@ -1446,6 +1455,14 @@ hbase> describe 't1'</programlisting>
                 </para>
             </answer>
         </qandaentry>
+        <qandaentry xml:id="faq.changing.rowkeys">
+            <question><para>Can I change a table's rowkeys?</para></question>
+            <answer>
+                <para>
+                    No.  See <xref linkend="changing.rowkeys" />.
+                </para>
+            </answer>
+        </qandaentry>
         <qandaentry xml:id="brand.new.compressor">
             <question><para>Why are logs flooded with '2011-01-10 12:40:48,407 INFO org.apache.hadoop.io.compress.CodecPool: Got
             brand-new compressor' messages?</para></question>