mysql视图在事务内部没有刷新（Hibernate / Spring）

Question

I am using Spring for DI and Hibernate for data access on a mySQL database. I have code inside a transaction that inserts a record in a table and then executes a view that queries that table and performs some aggregate calculations. The problem I see is that the record I just inserted during the same transaction, is not included in the view's calculated values. I run the same view in mySQL workbench and the inserted value is included in the view. Does anyone know what is causing this?

Answer 1

Ultimately, I had to call entityManager.refresh(Object entity) to refresh the entity for the view record I wanted updated. I think the problem resides in the fact that Hibernate cannot recognize that the view needs to be updated since it does not know that it is dependent (at the database level) upon the original entity that was updated. I presume that Hibernate is caching the records from the view and does not know that they need to get updated, even after a flush().

Hibernate sees the original table and the view as completely unrelated, when in reality the view is dependent upon the table and should be made "dirty" whenever the table changes. I don't know how to get Hibernate to recognize that.

Answer 2

Most probably you haven't flushed changes to the database yet. Hibernate does not know that there is connection between table you inserted rows and view that you are reading later. Flush entitymanager (or session or template) before querying view .

Answer 3

This is most probably caused by the default isolation level of MySQL which is REPEATABLE READ .

This means that your transaction in MySQL Workbench won't see changes until you end that transaction. Running a SELECT counts as a transaction.

You should see the changes in MySQL Workbench once you issue a commit (or rollback) there.

You probably want to change either the default isolation level for your installation to READ COMMITTED or change the isolation level of your session in MySQL Workbench to READ COMMITTED

Details on how you do that can be found in the manual.