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见过这么高并发( logons current)的数据库么?

今天在客户这里,在9206 RAC的集群环境中,偶然发现数据库的Logons Current指标超高。
高得超乎寻常,可以让我们直接判断为Bug,看看以下数据。

数据库环境:
SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.2.0.6.0 - 64bit Production
PL/SQL Release 9.2.0.6.0 - Production
CORE    9.2.0.6.0      Production
TNS for Solaris: Version 9.2.0.6.0 - Production
NLSRTL Version 9.2.0.6.0 - Production

看看logons current输出为:1.8447E+19
SQL> select name,value from v$sysstat where name like 'logons%';

NAME                                                                  VALUE
---------------------------------------------------------------- ----------
logons cumulative                                                  8674656
logons current                                                  1.8447E+19

改变列宽显示,这个天文数字呈现出来:
SQL> col name for a40
SQL> col value for 9999999999999999999999
SQL> select name,value from v$sysstat where name like 'logons%';

NAME                                                      VALUE
---------------------------------------- -----------------------
logons cumulative                                        8674700
logons current                              18446744073709550949

那么当前数据库有多少会话呢?
SQL> select count(*) from v$session;

  COUNT(*)
----------
      819
819个,logons current的统计数据会随着会话的变化而继续增加,并非停滞的溢出:
SQL> select name,value from v$sysstat where name like 'logons%';

NAME                                                      VALUE
---------------------------------------- -----------------------
logons cumulative                                        8674708
logons current                              18446744073709550952


SQL> select name,value from v$sysstat where name like 'logons%';

NAME                                                      VALUE
---------------------------------------- -----------------------
logons cumulative                                        8674722
logons current                              18446744073709550958

在Metalink上确认的Bug号是:2960012,在10.1中被修正。Bug的描述为:
When running in a RAC cluster, select from gv$sysstat can show a huge
value (1.8447E+19) for 'logons current' or 'logons cumulative'.
logons cumulative---Total number of logons since the instance started. Useful only in V$SYSSTAT. It gives an instance overview of all processes that logged on.
logons current-------Total number of current logons. Useful only in V$SYSSTAT.


那么这个天大的数字 18446744073709550958 ,该怎么读出口呢?

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无觅

By eygle on 2009-05-11 13:50 | Comments (4) | Case | FAQ | 2278 |

4 Comments

天文数字,呵呵

4g^2
=18446744073709551616

We are looking for experienced large scale, high performance MySQL DB Architect, any name you could recommend? Email me.
Thanks in advance for your help!

Diane


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