Jira issue originally created by user romanb:
During hydration when an association is encountered that is configured EAGER this entity is directly loaded through a separate SQL statement. This is inefficient for single-valued associations as it leads to the n+1 queries problem. This should be improved by somehow collecting all entities that need to be eagerly fetched and loading them in a single statement or in batches.
Comment created by romanb:
Update: This affects inverse sides of a one-one association since these can never be lazy as well as one-one owning sides that are configured EAGER.
Probably batching of collection loads is also somehow possible but all this needs quite some design and planning before implementation.
Comment created by @beberlei:
I implemented batching of eager loads for Many-To-One and Owning One-To-One associations so far as part of DDC-952.
Issue was closed with resolution "Fixed"