如何找出Oracle instance中当前打开游标open cursor的总数？

Maclean Liu(刘相兵

如何找出Oracle instance中当前打开游标open cursor的总数？

欢迎大家踊跃回答 各抒己见

vicry21

v$open_cursor可以不

repentance

v$sysstat;

不了峰

我这个好象是来自metalink来查询current open cursor的脚本


show parameter session_cached_cursor
drop view user_cursors;
create view user_cursors as
select
ss.username||'('||se.sid||') ' user_process, sum(decode(name,'recursive calls',value)) "Recursive Calls",
sum(decode(name,'opened cursors cumulative',value)) "Opened Cursors", sum(decode(name,'opened cursors current',value)) "Current Cursors"
        from v$session ss, v$sesstat se, v$statname sn
where  se.statistic# = sn.statistic#
                and (     name  like '%opened cursors current%'
                                OR name  like '%recursive calls%'
                                OR name  like '%opened cursors cumulative%')
                and  se.sid = ss.sid
                and     ss.username is not null
group by ss.username||'('||se.sid||') ';

ttitle 'Per Session Current Cursor Usage '
column USER_PROCESS format a25;
column "Recursive Calls" format 999,999,999;
column "Opened Cursors"  format 99,999;
column "Current Cursors"  format 99,999;

select * from user_cursors   
order by "Recursive Calls" desc;

warmbreeze

opened cursors current 是当前打开的cursor
v$open_cursor 是被cache的cursor

Maclean Liu(刘相兵

v$open_cursor  

包括多种cursor:


注意 11.2中  v$open_cursor 才有 cursor_type 这一字段 之前都没有 ， 即无法分清楚 是open cursor 还是cached cursor

SQL> select distinct cursor_type from v$open_cursor;

CURSOR_TYPE
----------------------------------------------------------------
SESSION CURSOR CACHED
OPEN
OPEN-RECURSIVE
DICTIONARY LOOKUP CURSOR CACHED
BUNDLE DICTIONARY LOOKUP CACHED


其中 部分是 CACHED的cursor 所以不能算作open cursor


可以利用以下查询近似 了解系统中 open cursor的总数，

SQL> select count(*)
  2    from v$open_cursor where cursor_type  in ('OPEN','OPEN-RECURSIVE');

  COUNT(*)
----------
        37


or


11g 以前 使用以下查询
select sum(a.value), b.name
from v$sesstat a, v$statname b
where a.statistic# = b.statistic#
and b.name = 'opened cursors current'
group by b.name;

SUM(A.VALUE) NAME
------------ ----------------------------------------------------------------
          35 opened cursors current

tonytang

也就是说10g以前是还是无法算出这个值的？牛啊！太细了！

saup007

对open cursor的监控

1. WITH a AS (SELECT VALUE init_open_cursors
   
2.              FROM v$parameter
   
3.             WHERE name = 'open_cursors'),
   
4.      b AS (SELECT MAX (max_cursors) curr_max_cursors
   
5.              FROM (  SELECT MAX (a.VALUE) max_cursors
   
6.                        FROM v$sesstat a, v$statname b, v$session s
   
7.                       WHERE     a.statistic# = b.statistic#
   
8.                             AND s.sid = a.sid
   
9.                             AND b.name = 'opened cursors current'
   
10.                    GROUP BY s.sid))
    
11. SELECT ROUND (b.curr_max_cursors / a.init_open_cursors * 100, 2) ratio
    
12.   FROM a, b;

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