监控数据库性能的SQL语句

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.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) \"#\ 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 \"Hitratio\"

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)/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 type,

count(name) num_instances, 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 1;

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) \"CACHEMISSES 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\\"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 wheretype='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, 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(*)) FROMdba_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;

19.对可疑/性能不好的Server Process来进行Trace.,可以用tkprof来分析

Trace的结果.比较方便.使用Unix的KSH. (1) start_trc: #!/bin/ksh if (( $# != 1 )) then

echo Usuage: start_trc pid fi

sid_serial=$(print \" connect / as sysdba; set heading off; set feedback off;

select a.sid,a.serial# from v\\$session a,v\\$process b wherea.paddr=b.addr and b.spid=$1; exit;

\" | sqlplus -s /nolog | grep -v 'Connected' | sed -e 's/\\([0-9]\\{1,\\}\\)/\\1,/' -e '/^$/d' ) if [[ -z $sid_serial ]] then

print \"Seems that this process $1 is not an Oracle process!\" exit 1 fi

print \"

connect / as sysdba;

execute dbms_system.set_sql_trace_in_session($sid_serial,true); exit;

\" | sqlplus -s /nolog

(2) stop_trc: #!/bin/ksh if (( $# != 1 )) then

echo Usuage: stop_trc pid fi

sid_serial=$(print \" connect / as sysdba;

set heading off; set feedback off;

select a.sid,a.serial# from v\\$session a,v\\$process b wherea.paddr=b.addr and b.spid=$1; exit;

\" | sqlplus -s /nolog | grep -v 'Connected' | sed -e 's/\\([0-9]\\{1,\\}\\)/\\1,/' -e '/^$/d' ) if [[ -z $sid_serial ]] then

print \"Seems that this process $1 is not an Oracle process!\" exit 1 fi

print \"

connect / as sysdba;

execute dbms_system.set_sql_trace_in_session($sid_serial,false); exit;

\" | sqlplus -s /nolog

20.查看Lock

SELECT sn.username, m.sid, m.type, DECODE(m.lmode, 0, 'None', 1, 'Null',

2, 'Row Share', 3, 'Row Excl.', 4, 'Share',

5, 'S/Row Excl.', 6, 'Exclusive',

lmode, ltrim(to_char(lmode,'990'))) lmode, DECODE(m.request,0, 'None', 1, 'Null',

2, 'Row Share', 3, 'Row Excl.', 4, 'Share',

5, 'S/Row Excl.', 6, 'Exclusive',

request, ltrim(to_char(m.request,'990'))) request, m.id1, m.id2

FROM v$session sn, v$lock m

WHERE (sn.sid = m.sid AND m.request != 0) OR ( sn.sid = m.sid AND m.request = 0 AND lmode != 4 AND (id1, id2) IN (

SELECT s.id1, s.id2 FROM v$lock s

WHERE request != 0 AND s.id1 = m.id1 AND s.id2 = m.id2 ) )

ORDER BY id1, id2, m.request;

select l.sid,s.serial#,s.username,s.terminal, decode(l.type,'RW','RW - Row Wait Enqueue', 'TM','TM - DML Enqueue', 'TX','TX - Trans Enqueue',

'UL','UL - User',l.type||'System') res, substr(t.name,1,10) tab,u.name owner, l.id1,l.id2,

decode(l.lmode,1,'No Lock', 2,'Row Share', 3,'Row Exclusive', 4,'Share',

5,'Shr Row Excl',

6,'Exclusive',null) lmode, decode(l.request,1,'No Lock', 2,'Row Share', 3,'Row Excl', 4,'Share',

5,'Shr Row Excl',

6,'Exclusive',null) request

from v$lock l, v$session s, sys.user$ u,sys.obj$ t where l.sid = s.sid and

s.type != 'BACKGROUND' and t.obj# = l.id1 and u.user# = t.owner#;