org.springframework.transaction.CannotCreateTransactionException: Could not create Hibernate transaction; nested exception is net.sf.hibernate.exception.GenericJDBCException: Cannot open connection
net.sf.hibernate.exception.GenericJDBCException: Cannot open connection
at net.sf.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:80)
at net.sf.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:69)
at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
Caused by: java.sql.SQLException: An SQLException was provoked by the following failure: com.mchange.v2.resourcepool.ResourcePoolException: A ResourcePool could not acquire a resource from its primary factory or source.
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:68)
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:57)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:213)
at com.mchange.v2.c3p0.PoolBackedDataSource.getConnection(PoolBackedDataSource.java:64)
at net.sf.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:33)
at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:292)
... 63 more
Caused by: com.mchange.v2.resourcepool.ResourcePoolException: A ResourcePool could not acquire a resource from its primary factory or source.
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAcquire(BasicResourcePool.java:870)
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:201)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:209)
... 66 more

Cause

This error is stating that Confluence cannot get a connection to the database.

Some possible causes are:

1. The database is down, possibly due to being overwhelmed.
2. The Application Server cannot reach the Database.
3. Your username and password that you used for your database in confluence_home/confluence.cfg.xml is incorrect.
4. There are not enough JDBC connections available during the upgrade process.

Resolution

1. Check that your database is up and running. If the problem has happened after a period of Confluence usage, check to make sure the database indices are installed correctly.
2. Find out why your Confluence server cannot establish a connection to the database.
3. Check that your username and password for your database is correct and hasn't been changed. This is configured in confluence.cfg.xml.
4. Check your DB connection pool settings. See Confluence slows and times out during periods of high load due to database connection pool .