oracle 开监控,Oracle 常用监控SQL

1.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(*)

from v$session_wait

group by event order by 4;

2.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;

3.监控表空间的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

4.监空文件系统的I/O比例：

select substr(a.file#,1,2) "#",substr(a.name,1,30) "name",a.status,a.bytes,

b.phyrds,b.phywrts

from v$datafile a,v$filestat b

where a.file#=b.file#

5.在某个用户下找所有的索引：

select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name

from user_ind_columns, user_indexes

where user_ind_columns.index_name = user_indexes.index_name

and user_ind_columns.table_name = user_indexes.table_name

order by user_indexes.table_type, user_indexes.table_name,

user_indexes.index_name, column_position;

6. 监控 SGA 的命中率

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;

7. 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;

8. 监控 SGA 中共享缓存区的命中率，应该小于1%

select sum(pins) "Total Pins", sum(reloads) "Total Reloads",

sum(reloads)/sum(pins) *100 libcache

from v$librarycache;

select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload perc