- A.检查表空间使用情况

SELECT B.TABLESPACE_NAME          TABLESPACE,
       A.EXTENT_MANAGEMENT        EXT_MGT,
       A.SEGMENT_SPACE_MANAGEMENT SEG_MGT,
       A.STATUS,
       A.LOGGING,
       B.TOTAL,
       B.FREE,
       B.USED_PCT
  FROM DBA_TABLESPACES A,
       (SELECT D.TABLESPACE_NAME TABLESPACE_NAME,
               ROUND((D.SUMBYTES / 1024 / 1024 / 1024), 2) || ‘GB‘ TOTAL,
               ROUND(DECODE(F.SUMBYTES, NULL, 0, F.SUMBYTES) / 1024 / 1024 / 1024,
                     2) || ‘GB‘ FREE,
               ROUND((D.SUMBYTES - DECODE(F.SUMBYTES, NULL, 0, F.SUMBYTES)) * 100 /
                     D.SUMBYTES,
                     2) || ‘%‘ USED_PCT
          FROM (SELECT TABLESPACE_NAME, SUM(BYTES) SUMBYTES
                  FROM DBA_FREE_SPACE
                 GROUP BY TABLESPACE_NAME) F,
               (SELECT TABLESPACE_NAME,
                       
                       SUM(BYTES) SUMBYTES
                  FROM DBA_DATA_FILES
                 GROUP BY TABLESPACE_NAME) D
         WHERE F.TABLESPACE_NAME(+) = D.TABLESPACE_NAME
         ORDER BY D.TABLESPACE_NAME) B
 WHERE A.TABLESPACE_NAME = B.TABLESPACE_NAME;

- B.检查是否有 offline 状态的表空间

SELECT FILE_ID AS ID,
       RELATIVE_FNO "FNO",
       ROUND(BYTES / 1024 / 1024) AS MBYTES,
       ROUND(MAXBYTES / 1024 / 1024) MAXMBYTES,
       BLOCKS,
       MAXBLOCKS,
       AUTOEXTENSIBLE "AUTO",
       INCREMENT_BY "INC",
       ROUND(USER_BYTES / 1024 / 1024) "NOW_MB",
       USER_BLOCKS,
       STATUS,
       ONLINE_STATUS "ONLINE_S"
  FROM DBA_DATA_FILES;

- C.在线日志是否存在小于 50M 的及状态不正常

SELECT A.GROUP#, A.STATUS, A.BYTES, B.MEMBER, A.ARCHIVED
  FROM V$LOG A, V$LOGFILE B
 WHERE A.GROUP# = B.GROUP#;

- D.检查锁阻塞

SELECT DECODE(REQUEST, 0, ‘阻塞者:‘, ‘等待者:‘) || SID SID,
       ID1,
       ID2,
       LMODE,
       REQUEST,
       TYPE
  FROM V$LOCK
 WHERE (ID1, ID2, TYPE) IN
       (SELECT ID1, ID2, TYPE FROM V$LOCK WHERE REQUEST > 0)
 ORDER BY ID1, REQUEST;

- E.查看是否有僵死进程

SELECT SPID FROM V$PROCESS WHERE ADDR NOT IN (SELECT PADDR FROM V$SESSION);

- F.检查是否有失效索引

SELECT OWNER, A.INDEX_NAME, A.INDEX_TYPE, A.STATUS
  FROM DBA_INDEXES A
 WHERE STATUS = ‘UNUSABLE‘;

SELECT A.INDEX_NAME, A.PARTITION_NAME, A.TABLESPACE_NAME, A.STATUS
  FROM DBA_IND_PARTITIONS A
 WHERE STATUS = ‘UNUSABLE‘;

- G.检查不起作用的约束

SELECT OWNER, CONSTRAINT_NAME, TABLE_NAME, CONSTRAINT_TYPE, STATUS
  FROM DBA_CONSTRAINTS
 WHERE STATUS = ‘DISABLE‘
   AND CONSTRAINT_TYPE = ‘P‘;

- H.缓冲区命中率

SELECT (1 - (SUM(DECODE(NAME, ‘PHYSICAL READS‘, VALUE, 0)) /
       (SUM(DECODE(NAME, ‘DB BLOCK GETS‘, VALUE, 0)) +
       SUM(DECODE(NAME, ‘CONSISTENT GETS‘, VALUE, 0))))) * 100 "HIT RATIO"
  FROM V$SYSSTAT;
  --应大于90%

- I.数据字典命中率

SELECT (1 - (SUM(GETMISSES) / SUM(GETS))) * 100 "HIT RATIO" FROM V$ROWCACHE;
--此命中率应大于 95%

- J.库缓存命中率

SELECT SUM(PINS) / (SUM(PINS) + SUM(RELOADS)) * 100 "HIT RATIO" FROM V$LIBRARYCACHE;
--此命中率应大于 95%

- K.内存中的排序

SELECT NAME, VALUE FROM V$SYSSTAT WHERE NAME LIKE ‘%SORTS%‘;
--如果存在大量的磁盘排序，则表明检查目前系统中消耗大量磁盘的 SQL 是否已经经过调整。

- L.磁盘中的排序

SELECT B.NAME, A.SID, A.VALUE
  FROM V$SESSTAT A, V$STATNAME B
 WHERE A.STATISTIC# = B.STATISTIC#
   AND B.NAME = ‘SORTS (DISK)‘
   AND A.VALUE > 0
   AND ROWNUM < 10
 ORDER BY A.VALUE DESC;
 --检查使用磁盘排序的会话信息，可以定位执行了大量磁盘排序的会话

- M.临时空间使用率

SELECT * FROM V$TEMP_SPACE_HEADER;

- N.检查ORACLE实例状态

SELECT INSTANCE_NAME, HOST_NAME, STARTUP_TIME, STATUS, DATABASE_STATUS FROM V$INSTANCE;
--其中“STATUS”表示ORACLE当前的实例状态，必须为“OPEN”；“DATABASE_STATUS”表示ORACLE当前数据库的状态，必须为“ACTIVE”

- O.检查ORACLE表空间的状态

SELECT TABLESPACE_NAME, STATUS FROM DBA_TABLESPACES;
--输出结果中STATUS应该都为ONLINE

- P.检查ORACLE所有数据文件状态

SELECT NAME, STATUS FROM V$DATAFILE;
--输出结果中“STATUS”应该都为“ONLINE”
SELECT FILE_NAME, STATUS FROM DBA_DATA_FILES;
--输出结果中“STATUS”应该都为“AVAILABLE”。

- R.检查所有回滚段状态

SELECT SEGMENT_NAME, STATUS FROM DBA_ROLLBACK_SEGS;
--输出结果中所有回滚段的“STATUS”应该为“ONLINE”。

- S.检查一些扩展异常的对象

SELECT SEGMENT_NAME,
       SEGMENT_TYPE,
       TABLESPACE_NAME,
       (EXTENTS / MAX_EXTENTS) * 100 PERCENT
  FROM SYS.DBA_SEGMENTS
 WHERE MAX_EXTENTS != 0
   AND (EXTENTS / MAX_EXTENTS) * 100 >= 95
 ORDER BY PERCENT;
 --如果有记录返回，则这些对象的扩展已经快达到它定义时的最大扩展值，对于这些对象要修改它的存储结构参数

- T.DISK READ最高的SQL语句的获取

SELECT SQL_TEXT
  FROM (SELECT * FROM V$SQLAREA ORDER BY DISK_READS)
 WHERE ROWNUM <= 5;

- U.性能最差的前10条SQL

SELECT *
  FROM (SELECT PARSING_USER_ID EXECUTIONS,
               SORTS,
               COMMAND_TYPE,
               DISK_READS,
               SQL_TEXT
          FROM V$SQLAREA
         ORDER BY DISK_READS DESC)
 WHERE ROWNUM < 10;

- V.检查运行很久的SQL

SELECT USERNAME,
       SID,
       OPNAME,
       ROUND(SOFAR * 100 / TOTALWORK, 0) || ‘%‘ AS PROGRESS,
       TIME_REMAINING,
       SQL_TEXT
  FROM V$SESSION_LONGOPS, V$SQL
 WHERE TIME_REMAINING <> 0
   AND SQL_ADDRESS = ADDRESS
   AND SQL_HASH_VALUE = HASH_VALUE;

- W.检查碎片程度高的表

SELECT SEGMENT_NAME TABLE_NAME, COUNT(*) EXTENTS
  FROM DBA_SEGMENTS
 WHERE OWNER NOT IN (‘SYS‘, ‘SYSTEM‘)
 GROUP BY SEGMENT_NAME
HAVING COUNT(*) = (SELECT MAX(COUNT(*))
                     FROM DBA_SEGMENTS
                    GROUP BY SEGMENT_NAME);

- X.检查死锁及处理

SELECT SID,
       SERIAL#,
       USERNAME,
       SCHEMANAME,
       OSUSER,
       MACHINE,
       TERMINAL,
       PROGRAM,
       OWNER,
       OBJECT_NAME,
       OBJECT_TYPE,
       O.OBJECT_ID
  FROM DBA_OBJECTS O, V$LOCKED_OBJECT L, V$SESSION S
 WHERE O.OBJECT_ID = L.OBJECT_ID
   AND S.SID = L.SESSION_ID;

- Y.失效的触发器

SELECT OWNER, TRIGGER_NAME, TABLE_NAME, STATUS
  FROM DBA_TRIGGERS
 WHERE STATUS = ‘DISABLED‘;

- Z.失败的JOB

SELECT JOB, WHAT, LAST_DATE, NEXT_DATE, FAILURES, BROKEN
  FROM DBA_JOBS
 WHERE SCHEMA_USER = ‘FCR51HOST‘;