监控数据库性能的SQL

文章作者 100test 发表时间 2008:03:13 14:41:36
来源 100Test.Com百考试题网

1. 监控事例的等待

0select 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.

2. 回滚段的争用情况

0select 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

0select 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.

4. 监控文件系统的 I/O 比例

0select 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

0select 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

0select 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

0select 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%

0select sum(pins) "Total Pins", sum(reloads) "Total Reloads",
sum(reloads)/sum(pins) *100 libcache
from v$librarycache.

0select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
from v$librarycache.

9. 显示所有数据库对象的类别和大小

0select count(name) num_instances ,type ,sum(source_size) source_size ,
sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size,
sum(source_size) sum(parsed_size) sum(code_size) sum(error_size) size_required
from dba_object_size
group by type order by 2.