I have a similar kind of association and
1.I use Criteria Restrictions to get all SideBlue's
2.There are 2000 SideBlues but about 750 SideBlue's does not have a SideRed.
When i try to get all SideBlue's the below queries get fired
1.A single LEFT OUTER JOIN query that fetches both SideBlue and SideRed using a Join
2.And then 750 queries using TwoPhaseLoad algorithm to get all SideRed's (though they do not exist as it is NULL)

@Entity
class SideBlue {
@Column(nullable = false)
private Integer timestamp;

@OneToOne(optional=true)
@JoinColumn(name="timestamp", referenceColumn="timestamp", insertable = false, updatable = false)
@Fetch(FetchMode.JOIN)
SideRed redSide;
}
@Entity
class SideRed {
@Column(nullable = false)
private Integer timestamp;
}

How do I avoid those 750 Queries as they are NULL and I do not expect any records. I use PROGRESS JDBC driver and OpenEdge hibernate dialect.