ORA-12839: cannot modify an object in parallel after modifying it
Cause: Within the same transaction, an attempt was made to perform parallel modification operations on a table after it had been modified. This is not permitted.
Action: Rewrite the transaction or break it up into two transactions: one containing the parallel modification and the second containing the initial modification operation.
ORA-12839: 不能在修改对象后并行修改该对象
ORA-12839 is thrown when an attempt is made to modify an object in parallel after modification has already been done.
此错误消息指出，试图对已修改过的对象进行并行修改。
这个错误的一个典型的案例是，在SRV_PARALLEL_DEGREE参数被设置为一个大的值的时候，尝试运行一些创建或修改对象的请求时，ORA-12839异常会发生。
1. 检查在运行修改时是否有SRV_PARALLEL_DEGREE参数被设置成NONZERO值；
2. 如果参数被设置成一个非允许值，请重新设置这个参数；
3. 尝试重新运行请求，如果还没有成功，可以考虑使用SERIAL主机参数来重新运行对象修改。