Oracle数据库的经典问题 snapshot too old是什么原因引起的 ORACLE经典错误求解:ORA-1555错误(Snapshot too old ) - ... 书上说是因为the rollback image need for read consistency has prbably been overwriteten by an active transaction. 我就奇怪了,如果一个transaction占用了一些回滚段,直到它commit前,这些回滚段空间应该被锁定了…