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

GROUPBY EVENT

ORDERBY 4;

3. --回滚段的争用情况

SELECTNAME, 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'

ORDERBY 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

GROUPBY TABLESPACE_NAME

ORDERBY 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

GROUPBY B.TABLESPACE_NAME, B.FILE_ID, B.BYTES

ORDERBY 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

ORDERBY T.CR_GET, T.PHY_IO;

9. --查看SGA区剩余可用内存

SELECTNAME,

　　　　　　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

ORDERBY 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

GROUPBY 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%

SELECTNAME,

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

WHERENAME 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

SELECTNAME, VALUE

FROM V$SYSSTAT

WHERENAME 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

ORDERBY 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

ORDERBY 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

ORDERBY 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

GROUPBY A.SID, S.TERMINAL, S.PROGRAM

ORDERBY COUNT(A.SID);