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监控数据库性能的语句

2019/09/13 来源:盐城信息港

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下面是一些监控数据库性能的语句,希望对大家有帮助:监控数据库性能的SQL语句1. 监控事例的等待select  event,

下面是一些监控数据库性能的语句,希望对大家有帮助:

监控数据库性能的SQL语句

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  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,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,

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;

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 where a.paddr=b.addr and b.spid=;

exit;

" | sqlplus -s /nolog | grep -v 'Connected' | sed -e 's/([0-9]\)/,/' -e '/^$/d' )

if [[ -z $sid_serial ]]

then

print "Seems that this process 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 where a.paddr=b.addr and b.spid=;

exit;

" | sqlplus -s /nolog | grep -v 'Connected' | sed -e 's/([0-9]\)/,/' -e '/^$/d' )

if [[ -z $sid_serial ]]

then

print "Seems that this process 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 / 查看本文来源

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