For deployments where logs are not important, it suffices to remove the logging line in the jbpm-context section of the jbpm.cfg.xml configuration file:

<service name='logging' factory='org.jbpm.logging.db.DbLoggingServiceFactory' />

In case you want to filter the logs, you need to write a custom implementation of the LoggingService that is a subclass of DbLoggingService. Also you need to create a custom logging ServiceFactory and specify that one in the factory attribute.