short term read lock / long term write lock Optimistic Locking : version column Pessimistic Locking : create a transaction to obtain long term lock Lock Modes : OPTIMISTIC : Obtain an optimistic read lock for all entities with version attr
short term read lock / long term write lock
Optimistic Locking : version column
Pessimistic Locking : create a transaction to obtain long term lock
Lock Modes :
OPTIMISTIC : Obtain an optimistic read lock for all entities with version attributes.
OPTIMISTIC_FORCE_INCREMENT : Obtain an optimistic read lock for all entities with version attributes, and increment the version attribute value .
READ : OPTIMISTIC .
WRITE : OPTIMISTIC_FORCE_INCREMENT .
PESSIMISTIC_READ : immediately obtain a long-term read lock on the data to prevent the data being modified or deleted . Other transactions may read the data while the lock is maintained, but not modify or delete the data.
PESSIMISTIC_WRITE : immediately obtain a long-term write lock on the data to prevent the data being read , modified or deleted .
PESSIMISTIC_FORCE_INCREMENT : immediately obtain a long-term lock on the data to prevent the data being modified or deleted , and increment the version attribute value.
NONE : no additional locking.
Question:
How to choose which mode to use????
参考资料 ：
https://docs.oracle测试数据/javaee/7/tutorial/doc/persistence-locking001.htm#GKJHZ
https://blogs.oracle测试数据/carolmcdonald/entry/jpa_2_0_concurrency_and
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