Hello. I am having a connection problem with MySQL. I did a search but got over 8000 results.

My hibernate.cfg.xml looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property>
<property name="hibernate.connection.password">********</property>
<property name="hibernate.connection.url">jdbc:mysql://dmzhost/ebl_price_catalog</property>
<property name="hibernate.connection.username">webservice</property>
<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="hibernate.c3p0.min_size">1</property>
<property name="hibernate.c3p0.max_size">5</property>
<property name="hibernate.c3p0.timeout">300</property>
<property name="hibernate.c3p0.max_statements">50</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
<mapping file="ediload.hbm.xml"/>
</session-factory>
</hibernate-configuration>

When I call buildSessionFactory, I get a stack trace from c3p0 that tells me its connection attempt failed and asks me if I have a server running at dmzhost:3306.

I am able to connect to MySQL from the command line:

mysql -h dmzhost -u webservice -D ebl_price_catalog -p

The host, dmzhost, is locally defined in /etc/hosts

Any ideas?

*** UPDATE ***

I noticed I am getting these errors:

WARNING: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@175b7f9 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
Dec 1, 2009 9:35:55 PM com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run
WARNING: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@175b7f9 -- APPARENT DEADLOCK!!! Complete Status:
Managed Threads: 3
Active Threads: 3
Active Tasks:
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@3bc1a1 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@12549c4 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@10df4e2 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)
Pending Tasks:
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@1485542
Pool thread stack traces:
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main]
java.lang.Thread.sleep(Native Method)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]
java.lang.Thread.sleep(Native Method)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,main]
java.lang.Thread.sleep(Native Method)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

I googled the deadlock problem, but all the hits seemed to be related to processes that were already running and performing queries. I tried setting the max_statements property to 0 with no change in symptoms.

Help?

The problem here seems to be with the org.gjt.mm.mysql.Driver class. I switched to the MySQL JDBC connector class (provided by MySQL) and all connections are working. I don't have time to dig into this, so I'll leave it at that.