From ef98468ea4c580b5d3bcdae2b3889703af4fb778 Mon Sep 17 00:00:00 2001
From: Marc Cromme <marc@indexdata.dk>
Date: Wed, 3 Jan 2007 15:34:50 +0000
Subject: [PATCH] added documentation on new filter load_balance

---
 doc/Makefile.am      |   12 +++++++---
 doc/book.xml         |   16 +++++++++++++-
 doc/load_balance.xml |   60 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+), 4 deletions(-)
 create mode 100644 doc/load_balance.xml

diff --git a/doc/Makefile.am b/doc/Makefile.am
index 2fa064f..67b7226 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,4 +1,4 @@
-## $Id: Makefile.am,v 1.32 2006-10-13 10:21:58 adam Exp $
+## $Id: Makefile.am,v 1.33 2007-01-03 15:34:50 marc Exp $
 docdir=$(datadir)/doc/@PACKAGE@
 
 SUBDIRS = common
@@ -12,14 +12,20 @@ MAINXML = $(srcdir)/book.xml
 XMLMAN = metaproxy.xml \
 	auth_simple.xml backend_test.xml bounce.xml \
 	frontend_net.xml \
-	http_file.xml log.xml multi.xml query_rewrite.xml \
+	http_file.xml \
+	load_balance.xml \
+	log.xml \
+	multi.xml query_rewrite.xml \
         record_transform.xml\
         sru_z3950.xml\
 	session_shared.xml template.xml virt_db.xml z3950_client.xml
 
 MANFILES = auth_simple.3mp backend_test.3mp  bounce.3mp \
         frontend_net.3mp \
-	http_file.3mp log.3mp multi.3mp query_rewrite.3mp \
+	http_file.3mp \
+	load_balance.3mp \
+	log.3mp \
+	multi.3mp query_rewrite.3mp \
         record_transform.3mp\
         sru_z3950.xml\
 	session_shared.3mp template.3mp virt_db.3mp z3950_client.3mp \
diff --git a/doc/book.xml b/doc/book.xml
index 26fd0a5..430b27b 100644
--- a/doc/book.xml
+++ b/doc/book.xml
@@ -17,7 +17,7 @@
      -->
      <!NOTATION PDF SYSTEM "PDF">
 ]>
-<!-- $Id: book.xml,v 1.44 2006-11-29 13:00:53 marc Exp $ -->
+<!-- $Id: book.xml,v 1.45 2007-01-03 15:34:50 marc Exp $ -->
 <book id="metaproxy">
  <bookinfo>
   <title>Metaproxy - User's Guide and Reference</title>
@@ -778,6 +778,20 @@ Figure out what additional information we need in:
    </section>
    
    <section>
+    <title><literal>load_balance</literal>
+     (mp::filter::LoadBalance)</title>
+    <para>
+     Performs load balancing for incoming Z39.50 init requests.
+     It is used together with the <literal>virt_db</literal> filter,
+     but unlike the <literal>multi</literal> filter it does send an
+     entire session to only one of the virtual backends. The 
+     <literal>load_balance</literal> filter is assuming that
+     all backend targets have equal content, and chooses the backend
+     with least load cost for a new session.
+   </para>
+   </section>
+   
+   <section>
    <title><literal>multi</literal>
      (mp::filter::Multi)</title>
     <para>
diff --git a/doc/load_balance.xml b/doc/load_balance.xml
new file mode 100644
index 0000000..fb5b25a
--- /dev/null
+++ b/doc/load_balance.xml
@@ -0,0 +1,60 @@
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN" 
+    "http://www.oasis-open.org/docbook/xml/4.1/docbookx.dtd" [
+ <!ENTITY copyright SYSTEM "copyright.xml">
+]>
+<!-- $Id: load_balance.xml,v 1.1 2007-01-03 15:34:50 marc Exp $ -->
+<refentry>
+ <refmeta>
+  <refentrytitle>load_balance</refentrytitle>
+  <manvolnum>3mp</manvolnum>
+   <refmiscinfo>Metaproxy Module</refmiscinfo>
+</refmeta>
+ 
+ <refnamediv>
+  <refname>load_balance</refname>
+  <refpurpose>balances load among Z39.50 targets</refpurpose>
+ </refnamediv>
+ 
+ <refsect1><title>DESCRIPTION</title>
+  <para>
+   This filter balances load among Z39.50 targets based on statistics
+   gathered on number of open sessions and number of open package requests. 
+  </para>
+ </refsect1>
+ 
+ <refsect1><title>EXAMPLES</title>
+  <para>
+   A typical configuration looks like this:
+   <screen><![CDATA[
+    <filter type="load_balance"/>
+]]>
+   </screen>
+  </para>
+ </refsect1> 
+ 
+ <refsect1><title>SEE ALSO</title>
+  <para>
+   <citerefentry>
+    <refentrytitle>metaproxy</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>
+  </para>
+ </refsect1>
+ 
+ &copyright;
+</refentry>
+
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
+sgml-indent-data:t
+sgml-parent-document:nil
+sgml-local-catalogs: nil
+sgml-namecase-general:t
+End:
+-->
-- 
1.7.10.4