Oracle 常用性能监控SQL语句

Oracle常用性能监控SQL语句
1.  --查看表锁 
SELECT * FROM SYS.V_$SQLAREA WHERE DISK_READS > 100;
2.  --监控事例的等待 
SELECT EVENT,
       SUM(DECODE(WAIT_TIME, 0, 0, 1)) "Prev",
       SUM(DECODE(WAIT_TIME, 0, 1, 0)) "Curr",
       COUNT(*) "Tot"
  FROM V$SESSION_WAIT
 GROUP BY EVENT
 ORDER BY 4;
3.  --回滚段的争用情况
SELECT NAME, WAITS, GETS, WAITS / GETS "Ratio"
  FROM V$ROLLSTAT A, V$ROLLNAME B
 WHERE A.USN = B.USN;
4.  --查看前台正在发出的SQL语句
SELECT USER_NAME, SQL_TEXT 　　
  FROM V$OPEN_CURSOR 　　
 WHERE SID IN (SELECT SID
                 FROM (SELECT SID, SERIAL#, USERNAME, PROGRAM 　　
                         FROM V$SESSION 　　
                        WHERE STATUS = 'ACTIVE'));
5.  --数据表占用空间大小情况
SELECT SEGMENT_NAME, TABLESPACE_NAME, BYTES, BLOCKS
  FROM USER_SEGMENTS
 WHERE SEGMENT_TYPE = 'TABLE'
 ORDER BY BYTES DESC, BLOCKS DESC;
6.  --查看表空间碎片大小
SELECT TABLESPACE_NAME,
       ROUND(SQRT(MAX(BLOCKS) / SUM(BLOCKS)) *
             (100 / SQRT(SQRT(COUNT(BLOCKS)))),
             2) FSFI
  FROM DBA_FREE_SPACE
 GROUP BY TABLESPACE_NAME
 ORDER BY 1;
7.  --查看表空间占用磁盘情况
SELECT B.FILE_ID 文件ID号,
       B.TABLESPACE_NAME 表空间名,
       B.BYTES 字节数,
       (B.BYTES - SUM(NVL(A.BYTES, 0))) 已使用,
       SUM(NVL(A.BYTES, 0)) 剩余空间,
       SUM(NVL(A.BYTES, 0)) / (B.BYTES) * 100 剩余百分比
  FROM DBA_FREE_SPACE A, DBA_DATA_FILES B
 WHERE A.FILE_ID = B.FILE_ID
 GROUP BY B.TABLESPACE_NAME, B.FILE_ID, B.BYTES
 ORDER BY B.FILE_ID;
8.  --查看session使用回滚段
SELECT R.NAME 回滚段名,
       S.SID,
       S.SERIAL#,
       S.USERNAME 用户名,
       T.STATUS,
       T.CR_GET,
       T.PHY_IO,
       T.USED_UBLK,
       T.NOUNDO,
       SUBSTR(S.PROGRAM, 1, 78) 操作程序
  FROM SYS.V_$SESSION S, SYS.V_$TRANSACTION T, SYS.V_$ROLLNAME R
 WHERE T.ADDR = S.TADDR
   AND T.XIDUSN = R.USN
 ORDER BY T.CR_GET, T.PHY_IO;
9.  --查看SGA区剩余可用内存
SELECT NAME,
       　　　　　　SGASIZE / 1024 / 1024　　　　　　　　"Allocated(M)",
       　　　　　　BYTES / 1024　　　　　　　　　　　 "**空间(K)",
       　　　　　　ROUND(BYTES / SGASIZE * 100, 2) 　　　"**空间百分比(%)" 　　
  FROM (SELECT SUM(BYTES) SGASIZE FROM SYS.V_$SGASTAT) S,
       SYS.V_$SGASTAT F 　　
 WHERE F.NAME = 'free memory';
10.  --监控表空间I/O比例
SELECT DF.TABLESPACE_NAME NAME,
       DF.FILE_NAME       "file",
       F.PHYRDS           PYR,
       F.PHYBLKRD         PBR,
       F.PHYWRTS          PYW,
       F.PHYBLKWRT        PBW
  FROM V$FILESTAT F, DBA_DATA_FILES DF
 WHERE F.FILE# = DF.FILE_ID
 ORDER BY DF.TABLESPACE_NAME;
11.  --监控SGA命中率
SELECT A.VALUE + B.VALUE "logical_reads",
       C.VALUE "phys_reads",
       ROUND(100 * ((A.VALUE + B.VALUE) - C.VALUE) / (A.VALUE + B.VALUE)) "BUFFER HIT RATIO"
  FROM V$SYSSTAT A, V$SYSSTAT B, V$SYSSTAT C
 WHERE A.STATISTIC# = 38
   AND B.STATISTIC# = 39
   AND C.STATISTIC# = 40;
12.  --监控 SGA 中字典缓冲区的命中率
SELECT PARAMETER,
       GETS,
       GETMISSES,
       GETMISSES / (GETS + GETMISSES) * 100 "miss ratio",
       (1 - (SUM(GETMISSES) / (SUM(GETS) + SUM(GETMISSES)))) * 100 "Hit ratio"
  FROM V$ROWCACHE
 WHERE GETS + GETMISSES <> 0
 GROUP BY PARAMETER, GETS, GETMISSES;
13.  --监控 SGA **享缓存区的命中率，应该小于1%
SELECT SUM(PINS) "Total Pins",
       SUM(RELOADS) "Total Reloads",
       SUM(RELOADS) / SUM(PINS) * 100 LIBCACHE
  FROM V$LIBRARYCACHE;
14.  --监控 SGA 中重做日志缓存区的命中率，应该小于1%
SELECT NAME,
       GETS,
       MISSES,
       IMMEDIATE_GETS,
       IMMEDIATE_MISSES,
       DECODE(GETS, 0, 0, MISSES / GETS * 100) RATIO1,
       DECODE(IMMEDIATE_GETS + IMMEDIATE_MISSES,
              0,
              0,
              IMMEDIATE_MISSES / (IMMEDIATE_GETS + IMMEDIATE_MISSES) * 100) RATIO2
  FROM V$LATCH
 WHERE NAME IN ('redo allocation', 'redo copy');
15.  --监控内存和硬盘的排序比率，最好使它小于 .10
SELECT NAME, VALUE
  FROM V$SYSSTAT
 WHERE NAME IN ('sorts (memory)', 'sorts (disk)');
16.  --监控字典缓冲区
SELECT SUM(GETS) "DICTIONARY GETS",
       SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
  FROM V$ROWCACHE;
17.  --非系统用户建在SYSTEM表空间中的表
SELECT OWNER, TABLE_NAME
  FROM DBA_TABLES
 WHERE TABLESPACE_NAME IN ('SYSTEM', 'USER_DATA')
   AND OWNER NOT IN
       ('SYSTEM', 'SYS', 'OUTLN', 'ORDSYS', 'MDSYS', 'SCOTT', 'HOSTEAC');
18.  --性能最差的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 < 100;

--用下列SQL 工具找出低效SQL ： 
SELECT EXECUTIONS,
       DISK_READS,
       BUFFER_GETS,
       ROUND((BUFFER_GETS - DISK_READS) / BUFFER_GETS, 2) HIT_RADIO,
       ROUND(DISK_READS / EXECUTIONS, 2) READS_PER_RUN,
       SQL_TEXT
  FROM V$SQLAREA
 WHERE EXECUTIONS > 0
   AND BUFFER_GETS > 0
   AND (BUFFER_GETS - DISK_READS) / BUFFER_GETS < 0.8
 ORDER BY 4 DESC;

19.  --读磁盘数超100次的sql
SELECT * FROM SYS.V_$SQLAREA WHERE DISK_READS > 100;
20.  --最频繁执行的sql
SELECT * FROM SYS.V_$SQLAREA WHERE EXECUTIONS > 100;
21.  --查询使用CPU多的用户session
SELECT A.SID,
       SPID,
       STATUS,
       SUBSTR(A.PROGRAM, 1, 40) PROG,
       A.TERMINAL,
       OSUSER,
       VALUE / 60 / 100 VALUE
  FROM V$SESSION A, V$PROCESS B, V$SESSTAT C
 WHERE C.STATISTIC# = 12
   AND C.SID = A.SID
   AND A.PADDR = B.ADDR
 ORDER BY VALUE DESC;
22.  --当前每个会话使用的对象数
SELECT A.SID, S.TERMINAL, S.PROGRAM, COUNT(A.SID)
  FROM V$ACCESS A, V$SESSION S
 WHERE A.OWNER <> 'SYS'
   AND S.SID = A.SID
 GROUP BY A.SID, S.TERMINAL, S.PROGRAM
 ORDER BY COUNT(A.SID);