[Oracle] Oracle性能监控语句

傷城~ 2022-08-01 14:00 232阅读 0赞

1. 查找事务进程ID

select p.SPID from v$session s,v$process p where s.PADDR=p.ADDR and s.SID in (select s.sid From v$transaction t,v$session s where t.addr=s.taddr);

2. 根据PID,找出消耗资源的SQL.  
select /\*+ ORDERED USE\_NL(st) \*/ sql\_text from v$sqltext a  
where a.hash\_value = (  
select sql\_hash\_value from v$session b  
where b.paddr = (  
select addr from v$process c  
where c.spid = '&spid'  
)  
)  
order by piece asc  
/  
然后对SQL进行优化.

3. 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;

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;

5. 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  
order by df.tablespace\_name;

6. 监控文件系统的 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\#;

7.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;

8. 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;

9. 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;

10. 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 percent"  
from v$librarycache;

11. 显示所有数据库对象的类别和大小

select 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;

12. 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');

13. 监控内存和硬盘的排序比率，最好使它小于 .10，增加 sort\_area\_size

SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)');

14. 监控当前数据库谁在运行什么SQL语句

SELECT osuser, username, sql\_text from v$session a, v$sqltext b  
where a.sql\_address =b.address order by address, piece;

15. 监控字典缓冲区

SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE;  
SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE;  
SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE;

后者除以前者,此比率小于1%,接近0%为好。

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"  
FROM V$ROWCACHE

16. 找ORACLE字符集

select \* from sys.props$ where name='NLS\_CHARACTERSET';

17. 监控 MTS

select busy/(busy+idle) "shared servers busy" from v$dispatcher;

此值大于0.5时，参数需加大

select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type='dispatcher';  
select count(\*) from v$dispatcher;  
select servers\_highwater from v$mts;

servers\_highwater接近mts\_max\_servers时，参数需加大

18. 碎片程度

select tablespace\_name,count(tablespace\_name) from dba\_free\_space group by tablespace\_name  
having count(tablespace\_name)>10;

alter tablespace name coalesce;  
alter table name deallocate unused;

create or replace view ts\_blocks\_v as  
select tablespace\_name,block\_id,bytes,blocks,'free space' segment\_name from dba\_free\_space  
union all  
select tablespace\_name,block\_id,bytes,blocks,segment\_name from dba\_extents;

select \* from ts\_blocks\_v;

select tablespace\_name,sum(bytes),max(bytes),count(block\_id) from dba\_free\_space  
group by tablespace\_name;

查看碎片程度高的表

SELECT segment\_name table\_name , COUNT(\*) extents  
FROM dba\_segments WHERE owner NOT IN ('SYS', 'SYSTEM') GROUP BY segment\_name  
HAVING COUNT(\*) = (SELECT MAX( COUNT(\*) ) FROM dba\_segments GROUP BY segment\_name);

19. 表、索引的存储情况检查

select segment\_name,sum(bytes) space,count(\*) ext\_quan from dba\_extents where  
tablespace\_name='&tablespace\_name' and segment\_type='TABLE' group by tablespace\_name,segment\_name;

select segment\_name,count(\*) from dba\_extents where segment\_type='INDEX' and owner='&owner'  
group by segment\_name;