oracle性能监控sql语句

性能监控之监控SQL语句

分析表
analyze table tablename compute statistics for all indexes;
analyze table tablename compute statistics for all indexed columns;
analyze table tablename compute statistics for table;

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;

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);

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;

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;

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;


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;

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;


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#;

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;

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;

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;

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);

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;

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));


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;

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

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

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;


 1、查询当前系统中正在执行的sql:

SELECT osuser, username, sql_text from v$session a, v$sqltext b
where a.sql_address =b.address order by address, piece;

2、查找死锁的语句:

SELECT l.session_id sid, s.serial#, l.locked_mode,l.oracle_username,
l.os_user_name,s.machine, s.terminal, o.object_name, s.logon_time
FROM v$locked_object l, all_objects o, v$session s
WHERE l.object_id = o.object_id
AND l.session_id = s.sid
ORDER BY sid, s.serial#;

3、查看oracle的权限角色:

select * from dba_role_privs;    授予用户和其他角色的角色  
select * from dba_sys_privs;     授予用户和其他角色的系统权限  
select * from dba_tab_privs;     数据库中对象的所有授权
select * from user_role_privs;   查看当前用户的角色

4、oracle 查看已经执行过的sql 这些是存在共享池中的：

select * from v$sqlarea t order by t.LAST_ACTIVE_TIME desc;

5、【获取oracle前10条最耗资源的sql语句】：

SELECT * FROM
  (
   SELECT PARSING_USER_ID
          EXECUTIONS,
          SORTS,
          COMMAND_TYPE,
          DISK_READS,
          sql_text
      FROM  v$sqlarea
     ORDER BY disk_reads DESC
   ) 
  WHERE ROWNUM<11;

----低效率sql
SELECT EXECUTIONS , DISK_READS, BUFFER_GETS,
　　ROUND((BUFFER_GETS-DISK_READS)/BUFFER_GETS,2) Hit_radio,
　　ROUND(DISK_READS/EXECUTIONS,2) Reads_per_run,
　　SQL_TEXT
　　FROM　 V$SQLAREA
　　WHERE　EXECUTIONS>0
　　AND　　 BUFFER_GETS > 0
　　AND (BUFFER_GETS-DISK_READS)/BUFFER_GETS < 0.8
　　ORDER BY 4 DESC


--耗费内存SQL
select s.schemaname schema_name,　　decode(sign(48 - command), 1,
　　to_char(command), 'Action Code #' || to_char(command) ) action,　　status
　　session_status,　 s.osuser os_user_name,　 s.sid,　　　　 p.spid ,　　　　 s.serial# serial_num,
　　nvl(s.username, '[Oracle process]') user_name,　 s.terminal terminal,
　　s.program program,　 st.value criteria_value　from v$sesstat st,　 v$session s　, v$process p
　　where st.sid = s.sid and　 st.statistic# = to_number('38') and　 ('ALL' = 'ALL'
　　or s.status = 'ALL') and p.addr = s.paddr order by st.value desc,　p.spid asc, s.username asc, s.osuser asc


---锁表

select     s.sid,s.machine,o.object_name,l.oracle_username,l.locked_mode,      
  'ALTER     SYSTEM     KILL     SESSION     '''||s.sid||',     '||s.serial#||''';'     Command      
  from     v$locked_object     l,v$session     s,all_objects     o      
  where     l.session_id=s.sid     and     l.object_id=o.object_id;