Problem using RiftSaw with MySQL

We have successfully installed RiftSaw with MySQL database as described here: https://issues.jboss.org/browse/RIFTSAW-327.

MySQL database is more stable then HSQL, but a bit slower. But after a while the disk space was full, we got the following error and RiftSaw was not able to run the BPEL processes anymore:

2011-04-26 11:04:09,055 WARN [org.hibernate.util.JDBCExceptionReporter] (ODEServer-920) SQL Error: 1114, SQLState: HY000
2011-04-26 11:04:09,055 ERROR [org.hibernate.util.JDBCExceptionReporter] (ODEServer-920) The table 'bpel_xml_data' is full
2011-04-26 11:04:09,055 ERROR [org.apache.ode.jacob.vpu.JacobVPU] (ODEServer-920) Method "run" in class "org.apache.ode.bpel.runtime.SCOPEACT" threw an unexpected exception.
javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not insert: [org.apache.ode.dao.jpa.bpel.XmlDataDAOImpl]

We have encountered, that the disc space was decreasing, because of increasing of the following database file: C:\ProgramData\MySQL\MySQL Server 5.5\data\ibdata1.

Then we tried to limit its size to 500 Mb in "my.ini" config-file, but we got the same error after this size has been reached (innodb_data_file_path=ibdata1:10M:autoextend:max:500M).

The 'bpel_xml_data' table contains all xml data that we use in our process and which we don't need after the process completion.

Later we got the same error for the 'bpel_message' table.

The events are disabled in all BPELs (process-events generate="none").

Our temporary solution is to stop the server, to drop the RiftSaw database, to create a new one and to restart the server. But in that way we have continuously to observe the server and that behavior is unacceptable for a productive use.

Is there some possibility to drop these tables or to clean their needless entries automatically after the process completion?