SHARE POOL利用堆（HEAP)的内存管理方式管理，在物理上由多个内存区（EXTENT)组成，内存区又由多个不同大小的CHUNK组成。而CHUNK又有可重用和空闲之分，并且它们分别有LRU LIST、FREE LIST、RESERVED LIST串联起来。
堆管理
Chunk的使用情况可由X$KSMSP内部视图查看。每个堆头上则包含了可使用的chunk列表和已使用的chunk列表。通过dump heap命令可以在trace文件中观察heap和extent的关系。
alter system set events 'immediate trace name heapdump level 2';
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案例：
SQL> select name,bytes/1024/1024 from v$sgainfo;
NAME BYTES/1024/1024
-------------------------------- ---------------
Fixed SGA Size 1.27566528
Redo Buffers 5.59765625
Buffer Cache Size 180
Shared Pool Size 104
Large Pool Size 4
Java Pool Size 4
Streams Pool Size 0
Shared IO Pool Size 0
Granule Size 4
Maximum SGA Size 498.875
Startup overhead in Shared Pool 52
NAME BYTES/1024/1024
-------------------------------- ---------------
Free SGA Memory Available 200
12 rows selected.
[oracle@node1 ~]$ more /u01/app/oracle/diag/rdbms/prod/prod/trace/prod_ora_14983.trc
Trace file /u01/app/oracle/diag/rdbms/prod/prod/trace/prod_ora_14983.trc
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1
System name: Linux
Node name: node1
Release: 2.6.18-194.el5
Version: #1 SMP Tue Mar 16 21:52:43 EDT 2010
Machine: i686
Instance name: prod
Redo thread mounted by this instance: 1
Oracle process number: 32
Unix process pid: 14983, image: oracle@node1 (TNS V1-V3)
*** 2014-07-02 14:58:47.532
*** SESSION ID:(32.758) 2014-07-02 14:58:47.532
*** CLIENT ID:() 2014-07-02 14:58:47.532
*** SERVICE NAME:(SYS$USERS) 2014-07-02 14:58:47.532
*** MODULE NAME:(sqlplus@node1 (TNS V1-V3)) 2014-07-02 14:58:47.532
*** ACTION NAME:() 2014-07-02 14:58:47.532
KGH Latch Directory Information
ldir state: 2 last allocated slot: 99
Slot [ 1] Latch: 0x200065ec Index: 1 Flags: 3 State: 2 next: (nil)
Slot [ 2] Latch: 0x3e75571c Index: 1 Flags: 3 State: 2 next: (nil)
......(省略）
Slot [ 99] Latch: 0x2002616c Index: 1 Flags: 3 State: 2 next: 0x1
******************************************************
HEAP DUMP heap name="sga heap" desc=0x200010b4
extent sz=0x7ad4 alt=124 het=32767 rec=9 flg=-126 opc=0
parent=(nil) owner=(nil) nex=(nil) xsz=0x0 heap=(nil)
fl2=0x60, nex=(nil)
ds for latch 1: 0x2002a990 0x2002b5c8 0x2002c200 0x2002ce38
reserved granule count 0 (granule size 4194304)
******************************************************
HEAP DUMP heap name="sga heap(1,0)" desc=0x2002a990
extent sz=0xfc4 alt=124 het=32767 rec=9 flg=-126 opc=0
parent=(nil) owner=(nil) nex=(nil) xsz=0x400000 heap=(nil)
fl2=0x20, nex=(nil)
latch set 1 of 1
durations enabled for this heap
reserved granules for root 0 (granule size 4194304)
EXTENT 0 addr=0x3b800000
Chunk 3b800038 sz= 24 R-freeable "reserved stoppe"
Chunk 3b800050 sz= 212888 R-free " "
Chunk 3b833fe8 sz= 24 R-freeable "reserved stoppe"
Chunk 3b834000 sz= 3981312 perm "perm " alo=3290272
EXTENT 1 addr=0x3bc00000
Chunk 3bc000