Alert_sid.log中出现Event 13740 Messages

检查alert_sid.log出现:

Starting ORACLE instance (normal)
~*ZJ0o"g)gC&qr0LICENSE_MAX_SESSION = 0ITPUB个人空间e.j:jY_H)V9v
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LICENSE_SESSIONS_WARNING = 0
L9@'~X*O0Interface type 1 lan1 10.0.0.0 configured from OCR for use as a cluster interconnectITPUB个人空间)| p*a b+F i\
Interface type 1 lan0 192.168.10.0 configured from OCR for use as  a public interface
G)@Ar9x$h7QF?|0WARNING 192.168.10.0 could not be translated to a network address
a!O2GoMk0DR'R)];u0Interface type 1 lan0 192.168.1.0 configured from OCR for use as  a public interface
8Wx7ap \2wyu0Picked latch-free SCN scheme 3ITPUB个人空间4u+N2S&`p5qL
Autotune of undo retention is turned on.ITPUB个人空间}/C(z0c4iU
LICENSE_MAX_USERS = 0
;^%C$G:cq)I [0SYS auditing is disabledITPUB个人空间qNI1q i[/uw3C
ksdpec: called for event 13740 prior to event group initializationITPUB个人空间v'X:y
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Starting up ORACLE RDBMS Version: 10.2.0.1.0.

Metalink解释:

"Event 13740 is an event id used when tracing ASH. It is detected when mapping the SGA duringITPUB个人空间q4FRy"Zn$H-jT-B"w
startup, so this message is only informational. There is no need to worry. There is no wayITPUB个人空间U-L2zz7K)}(\\3z
currently in the code of disabling this message"
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[6a6FN5r8r
我们看到13740事件就是在数据库启动时候,ASH匹配到SGA中的提示信息.

活动会话历史:Active Session History (ASH) statistics (activity of recent sessions)

SQL> select * from v$sgastat  where upper(name) like 'ASH%';

POOL         NAME                            BYTES
"Lg-d1bu]6u0------------ -------------------------- ----------
:N9MM'zY0shared pool  ASH buffers                   2097152

我们看到ASH在shared_pool中分配了2M.

在2个CPU的unix上查看:

SQL> select * from v$sgastat  where upper(name) like 'ASH%';

POOL         NAME                            BYTES
(e4d!_,u3q1r0------------ -------------------------- ----------
%eD4FZ vZO!V.}:uq0shared pool  ASH buffers                   4194304

可以发现是4M,所以ASH的size=2m*cpu个数

可以通过v$active_session_history查询历史记录,默认保存3天的数据ITPUB个人空间%_D2P{ UJ7`

SQL> select count(*) from dba_hist_active_sess_history;

  COUNT(*)
wCgB7t+s5? w-V0----------ITPUB个人空间A?9M6['g)M#@ml/M
      2885

SQL> select count(*) from v$active_session_history;

  COUNT(*)ITPUB个人空间MeSdu+A/Bz{
----------ITPUB个人空间?1r'KZ/L_i~
     11751

SQL> select to_char(a.sample_time,'yyyymmdd hh24:mi:ss')ITPUB个人空间sk*f(Zfx-s1tk&}*J
  2   from dba_hist_active_sess_history  a order by a.sample_time;

TO_CHAR(A.SAMPLE_ITPUB个人空间#@2bBZo4[|!wBQ
-----------------
.E"YMR"i?&x020080624 22:00:04ITPUB个人空间N3A2qx8y
20080624 22:00:04
K o7ZKr_FI020080624 22:00:04ITPUB个人空间\,Fv+b9vn|!D|nn
20080624 22:00:14
8A#[8y:Q1YZK$|7ZC020080624 22:00:14
k2~(u|
w0n||1@~020080624 22:00:14ITPUB个人空间;k|E!Cc*cv'FaC{ Rh
20080624 22:00:24
,hF ^k;[y;] f2oV020080624 22:00:24
/{@"i|1y o020080624 22:00:34
1u8Tg1B:ppB)V3t6w020080624 22:00:34ITPUB个人空间h1nS]*or]
20080624 22:00:44

dba_hist_active_session_history是每10秒收集一次

SQL> select max(a.sample_time)-min(a.sample_time) from dba_hist_active_sess_history  a;

MAX(A.SAMPLE_TIME)-MIN(A.SAMPLE_TIME)
Pc%j9PH tB$`0m0---------------------------------------------------------------------------
#`e ~2pA^0+000000007 12:53:57.483

SQL> select max(a.SAMPLE_TIME)-min(a.SAMPLE_TIME) from v$active_session_history aITPUB个人空间P?I0O?']?!Qg
  2  ;

MAX(A.SAMPLE_TIME)-MIN(A.SAMPLE_TIME)
.q
Y/p(D;~J0---------------------------------------------------------------------------
Y9L/J6y"j|T)q0+000000003 12:25:53.485

查看这两个表,可以看到dba_hist_active_sess_history 存储7天的数据,v$active_session_history 存储3天的数据,但是v$active_session_history存储的数据受ASH大小的限制,如果数据量大,只能存储当天的一段时间数据ITPUB个人空间%\4B},OW'K+\b

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