常用的Oracle性能监控sql

2017/02/10 14:06
阅读数 496

--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            "自由空间(K)",
             round(bytes / sgasize * 100, 2)    "自由空间百分比(%)"   
  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 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;

--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 0.10
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);

展开阅读全文
打赏
0
0 收藏
分享
加载中
更多评论
打赏
0 评论
0 收藏
0
分享
返回顶部
顶部