Oracle 常用性能监控SQL语句

原文：http://panhongbin100.iteye.com/blog/1596414
1. –查看表锁
SELECT * FROM SYS.V_SQLAREAWHEREDISKREADS>100;2.–监控事例的等待SELECTEVENT,SUM(DECODE(WAITTIME,0,0,1))“Prev”,SUM(DECODE(WAITTIME,0,1,0))“Curr”,COUNT(∗)“Tot”FROMVSESSION_WAIT
GROUP BY EVENT
ORDER BY 4;
3. –回滚段的争用情况
SELECT NAME, WAITS, GETS, WAITS / GETS “Ratio”
FROM VROLLSTATA,VROLLNAME 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 VOPEN_CURSOR 　　  
 WHERE SID IN (SELECT SID  
                 FROM (SELECT SID, SERIAL#, USERNAME, PROGRAM 　　  
                         FROM VSESSION 　　
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_SGASTATF　　WHEREF.NAME=‘freememory′;10.–监控表空间I/O比例SELECTDF.TABLESPACENAMENAME,DF.FILENAME“file”,F.PHYRDSPYR,F.PHYBLKRDPBR,F.PHYWRTSPYW,F.PHYBLKWRTPBWFROMVFILESTAT 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 VSYSSTATA,VSYSSTAT B, VSYSSTAT 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 VROWCACHE
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 VLIBRARYCACHE;14.–监控SGA中重做日志缓存区的命中率，应该小于1SELECTNAME,GETS,MISSES,IMMEDIATEGETS,IMMEDIATEMISSES,DECODE(GETS,0,0,MISSES/GETS∗100)RATIO1,DECODE(IMMEDIATEGETS+IMMEDIATEMISSES,0,0,IMMEDIATEMISSES/(IMMEDIATEGETS+IMMEDIATEMISSES)∗100)RATIO2FROMVLATCH
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 VSYSSTATWHERENAMEIN(‘sorts(memory)′,‘sorts(disk)′);16.–监控字典缓冲区SELECTSUM(GETS)“DICTIONARYGETS”,SUM(GETMISSES)“DICTIONARYCACHEGETMISSES”FROMVROWCACHE;
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;

1. –读磁盘数超100次的sql
   SELECT * FROM SYS.V_$SQLAREA WHERE DISK_READS > 100;
2. –最频繁执行的sql
   SELECT * FROM SYS.V_$SQLAREA WHERE EXECUTIONS > 100;
3. –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 VSESSIONA,VPROCESS B, V$SESSTAT C
   WHERE C.STATISTIC# = 12
   AND C.SID = A.SID
   AND A.PADDR = B.ADDR
   ORDER BY VALUE DESC;
4. –当前每个会话使用的对象数
   SELECT A.SID, S.TERMINAL, S.PROGRAM, COUNT(A.SID)
   FROM VACCESSA,VSESSION S
   WHERE A.OWNER <> ‘SYS’
   AND S.SID = A.SID
   GROUP BY A.SID, S.TERMINAL, S.PROGRAM
   ORDER BY COUNT(A.SID);