转载常用18条oracle性能监控sql

常用18条oracle性能监控sql

 

下面是收集的一些性能监控的sql,

Oracle数据库性能监控的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(*) "Tot"

    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

    order by df.tablespace_name;

 

4. 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#;

 

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 percent"

    from v$librarycache;

 

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。

 

    SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"

    FROM V$ROWCACHE

 

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

 

    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;