More documentation updates for incremental backup.

Add new terms to glossary. Add a reference to walsummarizer
to monitoring.sgml.

Matthias van de Meent and Robert Haas

Discussion: http://postgr.es/m/CAEze2WjhdVCqEe_qqEok3NA6DwUdOGSBjAxzmYdAqiaaH1uRcg@mail.gmail.com

doc/src/sgml/glossary.sgml

@@ -893,6 +893,27 @@
     </para>
    </glossdef>
   </glossentry>
+  <glossentry id="glossary-incremental-backup">
+   <glossterm>Incremental backup</glossterm>
+   <glossdef>
+    <para>
+     A special <glossterm linkend="glossary-basebackup">base backup</glossterm>
+     that for some files may contain only those pages that were modified since
+     a previous backup, as opposed to the full contents of every file. Like
+     base backups, it is generated by the tool <xref linkend="app-pgbasebackup"/>.
+    </para>
+    <para>
+     To restore incremental backups the tool <xref linkend="app-pgcombinebackup"/>
+     is used, which combines incremental backups with a base backup and
+     <glossterm linkend="glossary-wal">WAL</glossterm> to restore a
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm> to
+     a consistent state.
+    </para>
+    <para>
+     For more information, see <xref linkend="backup-incremental-backup"/>.
+    </para>
+   </glossdef>
+  </glossentry>
 
   <glossentry id="glossary-insert">
    <glossterm>Insert</glossterm>
@@ -2157,6 +2178,20 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-wal-summarizer">
+   <glossterm>WAL summarizer (process)</glossterm>
+   <glossdef>
+    <para>
+     A special <glossterm linkend="glossary-backend">backend process</glossterm>
+     that summarizes WAL data for
+     <glossterm linkend="glossary-incremental-backup">incremental backups</glossterm>.
+    </para>
+    <para>
+     For more information, see <xref linkend="runtime-config-wal-summarization"/>.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-wal-writer">
    <glossterm>WAL writer (process)</glossterm>
    <glossdef>

doc/src/sgml/monitoring.sgml

@@ -999,7 +999,8 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <literal>client backend</literal>, <literal>checkpointer</literal>,
        <literal>archiver</literal>, <literal>standalone backend</literal>,
        <literal>startup</literal>, <literal>walreceiver</literal>,
-       <literal>walsender</literal> and <literal>walwriter</literal>.
+       <literal>walsender</literal>, <literal>walwriter</literal> and
+       <literal>walsummarizer</literal>.
        In addition, background workers registered by extensions may have
        additional types.
       </para></entry>