Oracle常用监控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(*)
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

　　　　4.监空文件系统的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;

　　　　19.监控log_buffer的使用情况：(值最好小于1%，否则增加log_buffer 的大小)

select rbar.name,rbar.value,re.name,re.value,(rbar.value*100)/re.value||'%' "radio"
from v$sysstat rbar,v$sysstat re
where rbar.name='redo buffer allocation retries'
and re.name='redo entries';
 

　　　　20、查看运行过的SQL语句：

SELECT SQL_TEXT
FROM V$SQL

 

　　　　21. 查找所有表空间使用情况：

SELECT d.tablespace_name,
       space || 'M' "SUM_SPACE(M)",
       blocks "SUM_BLOCKS",
       space - nvl(free_space, 0) || 'M' "USED_SPACE(M)",
       round((1 - nvl(free_space, 0) / space) * 100, 2) || '%' "USED_RATE(%)",
       free_space || 'M' "FREE_SPACE(M)"
  FROM (SELECT tablespace_name,
               round(SUM(bytes) / (1024 * 1024), 2) space,
               SUM(blocks) blocks
          FROM dba_data_files
         GROUP BY tablespace_name) d,
       (SELECT tablespace_name,
               round(SUM(bytes) / (1024 * 1024), 2) free_space
          FROM dba_free_space
         GROUP BY tablespace_name) f
 WHERE d.tablespace_name = f.tablespace_name(+)
UNION ALL --如果有临时表空间
SELECT d.tablespace_name,
       space || 'M' "SUM_SPACE(M)",
       blocks sum_blocks,
       used_space || 'M' "USED_SPACE(M)",
       round(nvl(used_space, 0) / space * 100, 2) || '%' "USED_RATE(%)",
       nvl(free_space, 0) || 'M' "FREE_SPACE(M)"
  FROM (SELECT tablespace_name,
               round(SUM(bytes) / (1024 * 1024), 2) space,
               SUM(blocks) blocks
          FROM dba_temp_files
         GROUP BY tablespace_name) d,
       (SELECT tablespace_name,
               round(SUM(bytes_used) / (1024 * 1024), 2) used_space,
               round(SUM(bytes_free) / (1024 * 1024), 2) free_space
          FROM v$temp_space_header
         GROUP BY tablespace_name) f
 WHERE d.tablespace_name = f.tablespace_name(+)
 ORDER BY 1;

　　　　22. 查找trace文件的所在地

 

SELECT d.value || '/' || lower(rtrim(i.instance, chr(0))) || '_ora_' ||
       p.spid || '.trc' AS "trace_file_name"
  FROM (SELECT p.spid
          FROM v$mystat m, v$session s, v$process p
         WHERE m.statistic# = 1
           AND s.sid = m.sid
           AND p.addr = s.paddr) p,
       (SELECT t.instance
          FROM v$thread t, v$parameter v
         WHERE v.name = 'thread'
           AND (v.value = 0 OR t.thread# = to_number(v.value))) i,
       (SELECT VALUE FROM v$parameter WHERE NAME = 'user_dump_dest') d;