在日常的性能监控中，我们经常需要需要通过一段时间内数据库的逻辑读/物理读来大致反映数据库的性能情况，这里列出通过awr和statspack来获取相关数据（查询最近30天数据，除掉第一条和最后一条数据）
awr逻辑读

WITH A AS
 (SELECT B.SNAP_ID, SUM(VALUE)/1024/1024/1024*8192 VALUE
    FROM DBA_HIST_SYSSTAT B
   WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
          AND b.INSTANCE_NUMBER = &INST_NUM
     AND B.STAT_NAME IN ('session logical reads')
   GROUP BY B.SNAP_ID
   ORDER BY SNAP_ID)
SELECT A.SNAP_ID,
       LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "START_VALUE(G)",
       VALUE "END_VALUE(G)",
       TO_CHAR(END_INTERVAL_TIME,'YYYY-MM-DD HH24:MI:SS')"END_TIME",
       VALUE - LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "D-VALUE(G)"
  FROM A,(SELECT END_INTERVAL_TIME,SNAP_ID
    FROM DBA_HIST_SNAPSHOT B
   WHERE  B.DBID = (SELECT dbid FROM v$database)
     AND B.INSTANCE_NUMBER = &INST_NUM) B
     WHERE A.SNAP_ID=B.snap_id
     AND END_INTERVAL_TIME>=SYSDATE-30;

awr物理读

WITH A AS
 (SELECT B.SNAP_ID, SUM(VALUE)/1024/1024/1024*8192 VALUE
    FROM DBA_HIST_SYSSTAT B
   WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
          AND b.INSTANCE_NUMBER = &INST_NUM
     AND B.STAT_NAME IN ('physical reads')
   GROUP BY B.SNAP_ID
   ORDER BY SNAP_ID)
SELECT A.SNAP_ID,
       LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "START_VALUE(G)",
       VALUE "END_VALUE(G)",
       TO_CHAR(END_INTERVAL_TIME,'YYYY-MM-DD HH24:MI:SS')"END_TIME",
       VALUE - LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "D-VALUE(G)"
  FROM A,(SELECT END_INTERVAL_TIME,SNAP_ID
    FROM DBA_HIST_SNAPSHOT B
   WHERE  B.DBID = (SELECT dbid FROM v$database)
     AND B.INSTANCE_NUMBER = &INST_NUM) B
     WHERE A.SNAP_ID=B.snap_id
     AND END_INTERVAL_TIME>=SYSDATE-30;

statspack逻辑读

WITH A AS
 (SELECT B.SNAP_ID, SUM(VALUE)/1024/1024/1024*8192 VALUE
    FROM STATS$SYSSTAT B
   WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
     AND B.INSTANCE_NUMBER = &INST_NUM
     AND B.NAME IN ('session logical reads')
   GROUP BY B.SNAP_ID
   ORDER BY SNAP_ID)
SELECT A.SNAP_ID,
       LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "START_VALUE(G)",
       VALUE "END_VALUE(G)",
       TO_CHAR(SNAP_TIME, 'YYYY-MM-DD HH24:MI:SS') "END_TIME",
       VALUE - LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "D-VALUE(G)"
  FROM A,
       (SELECT SNAP_TIME, SNAP_ID
          FROM STATS$SNAPSHOT B
         WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
           AND B.INSTANCE_NUMBER = &INST_NUM) B
 WHERE A.SNAP_ID = B.SNAP_ID
  AND snap_time>=SYSDATE-30;

statspack物理读

WITH A AS
 (SELECT B.SNAP_ID, SUM(VALUE)/1024/1024/1024*8192 VALUE
    FROM STATS$SYSSTAT B
   WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
     AND B.INSTANCE_NUMBER = &INST_NUM
     AND B.NAME IN ('physical reads')
   GROUP BY B.SNAP_ID
   ORDER BY SNAP_ID)
SELECT A.SNAP_ID,
       LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "START_VALUE(G)",
       VALUE "END_VALUE(G)",
       TO_CHAR(SNAP_TIME, 'YYYY-MM-DD HH24:MI:SS') "END_TIME",
       VALUE - LAG(VALUE, 1, '0') OVER(ORDER BY A.SNAP_ID) "D-VALUE(G)"
  FROM A,
       (SELECT SNAP_TIME, SNAP_ID
          FROM STATS$SNAPSHOT B
         WHERE B.DBID = (SELECT DBID FROM V$DATABASE)
           AND B.INSTANCE_NUMBER = &INST_NUM) B
 WHERE A.SNAP_ID = B.SNAP_ID
 AND snap_time>=SYSDATE-30;