Unnecessary "left outer join". Probably this "left outer join" can be eliminated. OneToOne when optional=true and LAZY ---------------------------------------------------------------------------------------------------------------------- Key: HHH-4924 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-4924 Project: Hibernate Core Issue Type: Improvement Components: core Affects Versions: 3.3.1 Environment: n/a Reporter: Adam Wozniak Hi Relation between Person and Office is: 1 to {0 or 1} There a 3 classes (sources attached): * PersonPk * Person * Office SCENARIO -------- final Office office = em.find(Office.class, new PersonPk("adam", "woz")); System.out.println(office.getPerson().getZodiac()); I second line the following SQL is generated: select person0_.first_name as first1_22_1_, person0_.last_name as last2_22_1_, person0_.zodiac as zodiac22_1_, office1_.first_name as first1_23_0_, office1_.last_name as last2_23_0_, office1_.address as address23_0_ from PERSON person0_ left outer join OFFICE office1_ on person0_.first_name=office1_.first_name and person0_.last_name=office1_.last_name where person0_.first_name=? and person0_.last_name=? But we already know all columns for OFFICE so there is need to loaded them once again. In other words this SQL can be reduced to such SQL: select person0_.first_name as first1_22_1_, person0_.last_name as last2_22_1_, person0_.zodiac as zodiac22_1_, from PERSON person0_ where person0_.first_name=? and person0_.last_name=? Kind regards, Adam Woźniak / Poland -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.... - For more information on JIRA, see: http://www.atlassian.com/software/jira