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1. 检测数据库中的事件和等待

       SELECT event, total_waits, total_timeouts,time_waited, average_wait

       FROM v$system_event

2. 查询会话中的事件和等待时间

       select sid, event, total_waits,average_wait

       from v$session_event where sid=10;     

3. 查询等待进程 

       SELECT sid, seq#, event, wait_time, state

       FROM v$session_wait;

4. 监控全局区的性能 

       select * from v$sgastat;

5. 查询命中率

       select gethitratio

       from v$librarycache

       where namespace = 'SQL AREA';

6. 当前 sql 语句

       select sql_text, users_executing,

       executions, loads

       from v$sqlarea;

7. 查询高速缓存中的命中率

       select sum(pins) "Executions", sum(reloads) "Cache Misses",

       sum(reloads)/sum(pins)

       from v$librarycache;

8. 查询全局字典中的有效装载次数

       select namespace,pins,reloads,invalidations

       from v$librarycache;

9. 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;

10. 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;

11. 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#;

12. 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;

13. 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;

14. 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;

15. 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;

16. 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');

17. 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)');

18. 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

19. 找 ORACLE 字符集

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

20. 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

21. 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);

22. 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;

23 、找使用 CPU 多的用户 session

    12 是 cpu used by this 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;

posted on 2011-09-21 14:15 HUIKK 阅读(466) 评论(0)  编辑  收藏 所属分类: DB-DailyMmaintenance

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