Error appears when creating Advanced Workflow with long description

Steps to reproduce:
1. Start creation of Advanced Workflow (Adhoc or Review and Approve);
2. In Description field enter any text (approximately 300 symbols);
3. Choose any reviewer and click Finish button; -> System error message appears:

Please correct the errors below then click Finish.

• A system error happened during the operation: JDBC exception on Hibernate data access; nested exception is org.hibernate.exception.DataException: could not insert: [org.jbpm.context.exe.variableinstance.StringInstance]

Expected result:
Description field should have appropriate length limit or more friendly notification should inform the user;