[Oracle]监控数据库性能的SQL汇总

9. 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;

10. 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');

11. 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)');

12. 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;

13. 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。

14. 找ORACLE字符集

select * from sys.props$ where name='NLS_CHARACTERSET';

15. 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

16. 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);

17. 表、索引的存储情况检查

select segment_name,sum(bytes),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;

18、找使用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 order by value desc;
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