MySQL Bugs: #69557: Inconsistencies in Statement proxies created by LoadBalancingConnectionProxy

Bug #69557	Inconsistencies in Statement proxies created by LoadBalancingConnectionProxy
Submitted:	24 Jun 2013 12:15	Modified:	18 Nov 2013 15:05
Reporter:	Donnchadh Ó Donnabháin	Email Updates:
Status:	Verified	Impact on me:	None
Category:	Connector / J	Severity:	S3 (Non-critical)
Version:	5.1.25	OS:	Linux (CentOS 6.3)
Assigned to:	Assigned Account	CPU Architecture:	Any

Description:
Since JDBC4ResultSet doesn't directly implement a JDBC interface,
LoadBalancingConnectionProxy.isInterfaceJdbc(JDBC4ResultSet.class) returns false.
This means that it isn't proxied and the value return by getStatement() return the wrapped statement rather than the proxy.

I also don't see any logic here to ensure that the same object doesn't have multiple proxies, such that
 statement.executeQuery(query).getStatement() == statement, for example.

This results in issues such as https://hibernate.atlassian.net/browse/HHH-8210.

How to repeat:
* Enable loadbancing a connection url such as jdbc:mysql:replication://mysqlhost,mysqlreadonlyhost/mydatabase?roundRobinLoadBalance=true and using com.mysql.jdbc.ReplicationDriver
*
  PreparedStatement ps = connection.prepareStatement(myQuery);
  assertTrue(statement.executeQuery(query).getStatement() == statement);

Suggested fix:
Should the statement proxy call ResultSetInternalMethods.setStatementWrapper() ?

Hi Donnchadh,

Thanks for this report. We need to analyze the issue. Could you additionally describe your environment?

The environment is as follows
CentOS 6.3 - x86_64
JDK 1.7.0_21 - x86_64
Connector/J 5.1.25
Tomcat-pool 7.0.41

Also;
Spring Framework 3.2.2
Hibernate 4.2.2
MySQL 5.5.30
Tomcat 7.0.41

Verified by code review.