关于sharedpool的深入探讨(三)

link:
http://www.eygle.com/internal/shared_pool-3.htm
基本命令：
ALTERSESSIONSETEVENTS'immediatetracenameLIBRARY_CACHElevelLL';

其中LL代表Level级别,对于9.2.0及以后版本,不同Level含义如下:
Level=1,转储Librarycache统计信息
Level=2,转储hashtable概要
Level=4,转储Librarycache对象，只包含基本信息
Level=8,转储Librarycache对象，包含详细信息(包括childreferences,pinwaiters等)
Level=16,增加heapsizes信息
Level=32,增加heap信息

Librarycache由一个hash表组成,而hash表是一个由hashbuckets组成的数组.

每个hashbucket都是包含librarycachehandle的一个双向链表。
LibraryCacheHandle指向LibraryCacheObject和一个引用列表.
librarycache对象进一步分为:依赖表、子表和授权表等

我们看一下librarycache的结构:

通过
ALTERSESSIONSETEVENTS'immediatetracenameLIBRARY_CACHElevel4'
获得以下输出(这部分信息来自8i,Trace文件可以从www.eygle.com上找到)
点击这里下载:hsbi_ora_4614.trc
第一部分(等价于Level1):

LIBRARYCACHESTATISTICS:
getshitratiopinshitratioreloadsinvalidsnamespace
-------------------------------------------------------------------
6196581710.999916021932921120.99995119404380CRSR
796985580.99988324246148470.9999108135890TABL/PRCD/TYPE
1633990.99799261634020.9978948160BODY/TYBD
00.000000000.000000000TRGR
340.0294118350.057142900INDX
189480.9968862244880.995385500CLST
00.000000000.000000000OBJE
00.000000000.000000000PIPE
00.000000000.000000000LOB
00.000000000.000000000DIR
00.000000000.000000000QUEU
00.000000000.000000000OBJG
00.000000000.000000000PROP
00.000000000.000000000JVSC
00.000000000.000000000JVRE
00.000000000.000000000ROBJ
00.000000000.000000000REIP
00.000000000.000000000CPOB
1150710.99921791150710.99309997040EVNT
00.000000000.000000000SUMM
00.000000000.000000000DIMN
00.000000000.000000000CTX
00.000000000.000000000OUTL
00.000000000.000000000RULS
00.000000000.000000000RMGR
00.000000000.000000000UNUSED
00.000000000.000000000PPLN
00.000000000.000000000PCLS
00.000000000.000000000SUBS
00.000000000.000000000LOCS
00.000000000.000000000RMOB
00.000000000.000000000RSMD
6996541810.999911726182099550.999944023713380CUMULATIVE

这部分信息也就是v$librarycache中显示的.

第二部分(等价于Level2中的输出):

LIBRARYCACHEHASHTABLE:size=509count=354
BUCKET0:
BUCKET1:
BUCKET2:*
BUCKET3:
BUCKET4:
BUCKET5:*
BUCKET6:*
BUCKET7:
BUCKET8:**
BUCKET9:***
BUCKET10:*
BUCKET11:*
BUCKET12:***
BUCKET13:*
BUCKET14:*
BUCKET15:
BUCKET16:*
BUCKET17:
BUCKET18:*
BUCKET19:
BUCKET20:
BUCKET21:*
BUCKET22:
BUCKET23:
BUCKET24:*
BUCKET25:
BUCKET26:
BUCKET27:***
BUCKET28:
BUCKET29:**
BUCKET30:
BUCKET31:
BUCKET32:***
BUCKET33:*
BUCKET34:
BUCKET35:
BUCKET36:**
BUCKET37:
BUCKET38:**
BUCKET39:*
BUCKET40:*
BUCKET41:
BUCKET42:
BUCKET43:
BUCKET44:
BUCKET45:
BUCKET46:****
BUCKET47:
BUCKET48:
BUCKET49:*
BUCKET50:*
BUCKET51:
BUCKET52:***1