Which three statements are true about space usage alerts? (Choose three.) Alerts are issued only when the critical threshold for space available in a tablespace is breached. The sum of active extents and allocated user quotas is considered to compute space usage for an undo tablespace. Database alerts can provide warnings about low space availability at both tablespace and segment levels. Alerts are not issued for locally managed tablespaces that are offline or in read-only mode. A newly created locally managed tablespace is automatically assigned the default threshold values defined for a database. https://docs.oracle.com/cd/B28359_01/server.111/b28310/schema001.htm#ADMIN10120 ade https://docs.oracle.com/database/121/ADMIN/schema.htm#ADMIN014 cde 关于空间使用警报的以下三个陈述是正确的？ （选择三个）?? 不会为脱机或处于只读模式的本地管理的表空间发出警报。 活动范围和分配的用户配额的总和被视为计算undo表空间的空间使用情况。 自动为新创建的本地管理的表空间分配为数据库定义的默认阈值。