From 23b0b876741f7968141fa6a04124940b3a6a62cf Mon Sep 17 00:00:00 2001
From: Pinaki Poddar <ppoddar@apache.org>
Date: Sun, 8 Mar 2009 18:11:55 +0000
Subject: [PATCH] OPENJPA-966: Support MySQL Replication Driver

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@751487 13f79535-47bb-0310-9956-ffa450edef68
---
 .../openjpa/jdbc/kernel/JDBCStoreManager.java |  5 +++
 .../openjpa/jdbc/sql/MySQLDictionary.java     |  7 ++++
 .../src/doc/manual/ref_guide_dbsetup.xml      | 35 +++++++++++++++++--
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/JDBCStoreManager.java b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/JDBCStoreManager.java
index 3c7c4b353..304b4aac9 100644
--- a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/JDBCStoreManager.java
+++ b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/kernel/JDBCStoreManager.java
@@ -641,6 +641,11 @@ public class JDBCStoreManager
     }
 
     public Collection flush(Collection sms) {
+        try {
+            if (_conn != null && _conn.getInnermostDelegate().isReadOnly())
+                _conn.setReadOnly(false);
+        } catch (SQLException e) {
+        }
         return _conf.getUpdateManagerInstance().flush(sms, this);
     }
 
diff --git a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
index 3d25d95a4..1dfcc6613 100644
--- a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
+++ b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
@@ -146,6 +146,13 @@ public class MySQLDictionary
         }
     }
 
+    public Connection decorate(Connection conn)  throws SQLException {
+        String driver = conf.getConnectionDriverName();
+        if ("com.mysql.jdbc.ReplicationDriver".equals(driver))
+            conn.setReadOnly(true);
+        return conn;
+    }
+    
     private static int[] getMajorMinorVersions(String versionStr)
         throws IllegalArgumentException {
         int beginIndex = 0;
diff --git a/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml b/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml
index 7747ee1a9..eee8e7851 100644
--- a/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml
+++ b/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml
@@ -3215,9 +3215,40 @@ action is used. (See <xref linkend="ref_guide_schema_schematool"/> for
 more info about <literal>deleteTableContents</literal>.) Defaults to
 <literal>false</literal>, since the statement may fail if using InnoDB
 tables and delete constraints.
-                    </para>
+                    </para>
+                    
                 </listitem>
-            </itemizedlist>
+            </itemizedlist>
+            
+                    <para>
+Starting with Connector/J 3.1.7, MySQL supports a variant of the driver 
+<literal>com.mysql.jdbc.ReplicationDriver</literal> that automatically sends 
+queries to a read/write master, or a failover or round-robin load balanced set 
+of slaves based on the state of read-only status of the connection. 
+See  <ulink url="http://dev.mysql.com/doc/refman/5.1/en/connector-j-reference-replication-connection.html">
+MySQL Reference</ulink> for more details. 
+                    </para>
+                    <para>
+This replication feature can be used transparently with OpenJPA application by
+following configuration:
+                    </para>
+        <itemizedlist>
+           <listitem>
+             <para>
+<literal>openjpa.ConnectionDriverName: com.mysql.jdbc.ReplicationDriver</literal>
+             </para>
+           </listitem>
+           <listitem>
+             <para>
+<literal>openjpa.ConnectionFactoryProperties: autoReconnect=true,roundRobinLoadBalance=true</literal>
+             </para>
+             <para>
+OpenJPA will use a read-only connection with replicated database configuration
+and will automatically switch the connection to a non-readonly mode if the
+transaction is writing to the database.             
+             </para>
+           </listitem>
+         </itemizedlist>
         </section>
         <section id="ref_guide_dbsetup_dbsupport_oracle">
             <title>