svn commit - mysqldoc@docsrva: r7491 - trunk/refman-common

[mcbrown]

Author: mcbrown
Date: 2007-08-21 12:49:46 +0200 (Tue, 21 Aug 2007)
New Revision: 7491

Log:
Added the connect_server() description and example



Modified:
   trunk/refman-common/mysql-proxy.xml


Modified: trunk/refman-common/mysql-proxy.xml
===================================================================
--- trunk/refman-common/mysql-proxy.xml	2007-08-21 10:09:49 UTC (rev 7490)
+++ trunk/refman-common/mysql-proxy.xml	2007-08-21 10:49:46 UTC (rev 7491)
Changed blocks: 5, Lines Added: 42, Lines Deleted: 1; 2505 bytes

@@ -1467,8 +1467,45 @@
 
       <title>Capturing a connection with <literal>connect_server()</literal></title>
 
-      <para></para>
+      <para>
+        When the proxy accepts a connection from a MySQL client, the
+        <function>connect_server()</function> function is called.
+      </para>
 
+      <para>
+        There are no arguments to the function, but you can use and if
+        necessary manipulate the information in the
+        <literal>proxy.connection</literal> table, which is unique to
+        each client session.
+      </para>
+
+      <para>
+        For example, if you have multiple backend servers then you can
+        set the server to be used by that connection by setting the
+        value of <literal>proxy.connection.backend_ndx</literal> to a
+        valid server number. The code below will choose between two
+        servers based on whether the current time in minutes is odd or
+        even:
+      </para>
+
+<programlisting>function connect_server()
+        print("--> a client really wants to talk to a server")
+        if (tonumber(os.date("%M")) % 2 == 0) then
+                proxy.connection.backend_ndx = 2
+                print("Choosing backend 2")
+        else
+                proxy.connection.backend_ndx = 1
+                print("Choosing backend 1")
+        end
+        print("Using " .. proxy.servers[proxy.connection.backend_ndx].address)
+end</programlisting>
+
+      <para>
+        In this example the IP address/port combination is also
+        displayed by accessing the information from the internal
+        <literal>proxy.servers</literal> table.
+      </para>
+
     </section>
 
     <section id="mysql-proxy-scripting-read-handshake">

@@ -1990,6 +2027,7 @@
       </para>
     </note>
 
+<!--
     <para>
       You can control how clients are distributed among backend servers,
       for example, choosing slaves in a master/slave replication

@@ -2038,6 +2076,7 @@
       <xref
   linkend="mysql-proxy-using-customresultset"/>.
     </para>
+-->
 
     <section id="mysql-proxy-using-admin">
 

@@ -2095,6 +2134,7 @@
 
     </section>
 
+<!--
     <section id="mysql-proxy-using-connfilter">
 
       <title>Using MySQL Proxy to Filter Connections</title>

@@ -2154,6 +2194,7 @@
       </para>
 
     </section>
+-->
 
   </section>