We have migrated from Hibernate 5 to 6.
Since this migration, we have noticed a downgrade in performance when lazy loading a collection of entity.
I have reproduced the issue with the attached entities.
In a postgresql DB, we have 150 000 books and 750 000 pages.
When we load all books and then via the association all pages linked to books (FetchType.LAZY and FetchMode.SUBSELECT) :
* it takes several minutes with the 6.2.4 version of hibernate
* it takes several seconds with the 5.6.15 version of hibernate
After some analysis, we have noticed that we stay a lot of a time in {{ListResultsConsumer}}.
When we aggregate the entities, it use the {{Results}} class and the addUnique method seem to have difficulties to handle a large bulk of entities to aggregate.
It seems to be linked to [https://hibernate.atlassian.net/browse/HHH-15479|https://hibernate.atlassian.net/browse/HHH-15479|smart-link]
Do we need do something wrong in our mapping ? Do we have miss something during migration ?
Thanks & Regards |
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