Oracle性能监控常用命令

---

--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;

--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;

--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;

--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#;

--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 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;

--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 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');

--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

--找ORACLE字符集

select * from sys.props$ where name='NLS_CHARACTERSET';

--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;

--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) space, 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;

--检测数据库中的事件和等待

SELECT event, total_waits, total_timeouts,time_waited, average_wait FROM v$system_event

--查询会话中的事件和等待时间

select sid, event, total_waits,average_wait from v$session_event where sid=10;

--查询等待进程

SELECT sid, seq#, event, wait_time, state FROM v$session_wait;

--当前 sql 语句

select sql_text, users_executing, executions, loads from v$sqlarea;

--查询高速缓存中的命中率

select sum(pins) "Executions",
       sum(reloads) "Cache Misses",
       sum(reloads) / sum(pins)
  from v$librarycache;

--查询全局字典中的有效装载次数

select namespace,pins,reloads,invalidations from v$librarycache;

--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;

--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;

--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#;

--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 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;

--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 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');

--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

--找 ORACLE 字符集

select * from sys.props$ where name='NLS_CHARACTERSET';

--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
----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;

--查看表锁
select * from sys.v_$sqlarea where disk_reads>100

--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

--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

--查看前台正在发出的SQL语句
select user_name, sql_text 　　
  from v$open_cursor 　　
 where sid in (select sid
                 from (select sid, serial#, username, program 　　
                         from v$session 　　
                        where status = 'ACTIVE'))

--数据表占用空间大小情况
select segment_name, tablespace_name, bytes, blocks
  from user_segments
 where segment_type = 'TABLE'
 ORDER BY bytes DESC, blocks DESC

--查看表空间碎片大小
select tablespace_name,
       round(sqrt(max(blocks) / sum(blocks)) *
             (100 / sqrt(sqrt(count(blocks)))),
             2) FSFI
  from dba_free_space
 group by tablespace_name
 order by 1
    
--查看表空间占用磁盘情况
select b.file_id 文件ID号,
       b.tablespace_name 表空间名,
       b.bytes 字节数,
       (b.bytes - sum(nvl(a.bytes, 0))) 已使用,
       sum(nvl(a.bytes, 0)) 剩余空间,
       sum(nvl(a.bytes, 0)) / (b.bytes) * 100 剩余百分比
  from dba_free_space a, dba_data_files b
 where a.file_id = b.file_id
 group by b.tablespace_name, b.file_id, b.bytes
 order by b.file_id

--查看session使用回滚段
SELECT  r.name 回滚段名,
        s.sid,
        s.serial#,
        s.username 用户名,
        t.status,
        t.cr_get,
        t.phy_io,
        t.used_ublk,
        t.noundo,
        substr(s.program, 1, 78) 操作程序
FROM   sys.v_$session s,sys.v_$transaction t,sys.v_$rollname r
WHERE  t.addr = s.taddr and t.xidusn = r.usn
ORDER  BY t.cr_get,t.phy_io

--查看SGA区剩余可用内存
select name,
　　　　　　sgasize/1024/1024　　　　　　　　"Allocated(M)",
　　　　　　bytes/1024　　　　　　　　　　　 "**空间(K)",
　　　　　　round(bytes/sgasize*100, 2)　　　"**空间百分比(%)"
　　 from   (select sum(bytes) sgasize from sys.v_$sgastat) s, sys.v_$sgastat f
　　 where  f.name = 'free memory'

--监控表空间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

--监控SGA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 **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

--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')

--监控内存和硬盘的排序比率，最好使它小于 .10
SELECT name, value
FROM v$sysstat
WHERE name IN ('sorts (memory)', 'sorts (disk)')

--监控字典缓冲区
SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
FROM V$ROWCACHE

--非系统用户建在SYSTEM表空间中的表
SELECT owner,table_name
FROM DBA_TABLES
WHERE tablespace_name in('SYSTEM','USER_DATA') AND
      owner NOT IN('SYSTEM','SYS','OUTLN', 'ORDSYS','MDSYS','SCOTT', 'HOSTEAC')

--性能最差的SQL

SELECT * FROM ( SELECT PARSING_USER_ID EXECUTIONS,SORTS,COMMAND_TYPE,DISK_READS,sql_text
                FROM v$sqlarea
                ORDER BY disk_reads DESC)
WHERE ROWNUM<100
                             
--读磁盘数超100次的sql

select * from sys.v_$sqlarea where disk_reads>100

--最频繁执行的sql

select * from sys.v_$sqlarea where executions>100

--查询使用CPU多的用户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

--当前每个会话使用的对象数
SELECT a.sid,s.terminal,s.program,count(a.sid)
FROM V$ACCESS a,V$SESSION s
WHERE a.owner <> 'SYS'AND s.sid = a.sid
GROUP BY a.sid,s.terminal,s.program
ORDER BY count(a.sid)

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