【DB笔试面试156】在Oracle中，如何查询数据库系统或当前会话的Redo和Undo的生成量？

SELECT NAME,
       VALUE
FROM   V$SYSSTAT
WHERE  NAME = 'redo size';

CREATE OR REPLACE VIEW VW_REDO_SIZE_LHR AS 
SELECT VALUE REDO_SIZE
FROM   V$MYSTAT   MY,
       V$STATNAME  ST
WHERE  MY.STATISTIC# =ST.STATISTIC#
AND    ST.NAME = 'redo size';

CREATE OR REPLACE VIEW VW_REDO_UNDO_LHR AS 
SELECT (SELECT NB.VALUE
          FROM V$MYSTAT NB, V$STATNAME ST
         WHERE NB.STATISTIC# = ST.STATISTIC#
           AND ST.NAME = 'redo size') REDO,
       (SELECT NB.VALUE
          FROM V$MYSTAT NB, V$STATNAME ST
         WHERE NB.STATISTIC# = ST.STATISTIC#
           AND ST.NAME = 'undo change vector size') UNDO
  FROM DUAL;