ORACLE常用性能监控SQL语句

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2020-10-28

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Oracle 常用性能监控 SQL 语句

--查看表锁

select * from sys.v_$sqlarea where disk_reads>100

--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

--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

--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'))

--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

--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

--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

--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

--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'

--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

--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

--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

--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

--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')

--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)')

--监控字典缓冲区

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"

FROM V$ROWCACHE

--非系统用户建在 SYSTEM 表空间中的表