[hibernate-issues] [Hibernate-JIRA] Resolved: (EJB-375) getSingleResult potentially generates out of memory by calling list()

getSingleResult potentially generates out of memory by calling list() --------------------------------------------------------------------- Key: EJB-375 URL: http://opensource.atlassian.com/projects/hibernate/browse/EJB-375 Project: Hibernate Entity Manager Issue Type: Bug Components: EntityManager Affects Versions: 3.3.2.GA Environment: any Reporter: Pascal P. Pochet Assignee: Emmanuel Bernard Fix For: 3.4 calling list() while the user expects a single result has potential major flow: it's easy to trigger an out of memory situation where nobody would expect it... like getSingleResult("select CURRENT_TIME from AN_ENTITY_CONTAINING_ZILLIONS_OF_RECORDS") ; (and it is also a performance problem when it doesn't trigger the out of heap space... and a design issue: why fetching something the caller is not asking for ? with all the consequences on the cache...) easy to circumvent by changing List result = query.list(); to List result = query.setMaxResults(2).list(); (so we keep the functionality of alerting developer when query is wrongly returning multiple results when it should not...) and em.throwPersistenceException( new NonUniqueResultException( "result returns " + uniqueResult.size() + " elements") ); to em.throwPersistenceException( new NonUniqueResultException( "result returns more than 1 element") );