힙 메모리 구조

SGA 힙 덤프 데모

******************************************************
HEAP DUMP heap name="sga heap"  desc=700000000000190
 extent sz=0xfe0 alt=248 het=32767 rec=9 flg=-126 opc=0
 parent=0 owner=0 nex=0 xsz=0x0 heap=0
 fl2=0x60, nex=0
 ds for latch 1: 0x700000000052160 0x7000000000539b8 0x700000000055210 0x700000000056a68
 ds for latch 2: 0x70000000005ba28 0x70000000005d280 0x70000000005ead8 0x700000000060330
 ds for latch 3: 0x7000000000652f0 0x700000000066b48 0x7000000000683a0 0x700000000069bf8
 reserved granule count 0 (granule size 16777216)
******************************************************
HEAP DUMP heap name="sga heap(1,0)"  desc=700000000052160
 extent sz=0xfe0 alt=248 het=32767 rec=9 flg=-126 opc=0
 parent=0 owner=0 nex=0 xsz=0x1000000 heap=0
 fl2=0x20, nex=0
 latch set 1 of 3
 durations enabled for this heap
 reserved granules for root 0 (granule size 16777216)
EXTENT 0 addr=700000191000000
  Chunk  700000191000058 sz=       48  R-freeable  "reserved stoppe"
  Chunk  700000191000088 sz=   839496  R-free      "               "
  Chunk  7000001910ccfd0 sz=       48  R-freeable  "reserved stoppe"
  Chunk  7000001910cd000 sz= 15937536    perm      "perm           "  alo=5773792
EXTENT 1 addr=7000001b3000000
  Chunk  7000001b3000058 sz=       48  R-freeable  "reserved stoppe"
  Chunk  7000001b3000088 sz=   839496  R-free      "               "
  Chunk  7000001b30ccfd0 sz=       48  R-freeable  "reserved stoppe"
  Chunk  7000001b30cd000 sz= 15934744    perm      "perm           "  alo=15934744
  Chunk  7000001b3fff518 sz=     2792    free      "               "
EXTENT 2 addr=7000001b8000000
  Chunk  7000001b8000058 sz=       48  R-freeable  "reserved stoppe"
  Chunk  7000001b8000088 sz=   839496  R-free      "               "
  Chunk  7000001b80ccfd0 sz=       48  R-freeable  "reserved stoppe"
  Chunk  7000001b80cd000 sz= 15927856    perm      "perm           "  alo=15927856
...

> SGA 는 여러 개의 서브힙으로 구성됨 - "sga heap(1,0)" ... "sga heap (3,3)"
> 하나의 서브힙에는 여러 개의 익스텐트(Extent 0, Extent 1, ...)가 존재하고, 각 익스텐트는 여러개의 청크(Chunk)가 존재
> 각 청크는 perm, free, recreate 등의 메모리 상태를 가지며, "fixed allocation", "reserved stoppe", "perm" 과 같은 메모리 유형을 가짐

SGA 힙 덤프 데모 (서브힙 확인)

HEAP DUMP heap name="sga heap(1,0)"  desc=700000000052160
HEAP DUMP heap name="sga heap(1,1)"  desc=7000000000539b8
HEAP DUMP heap name="sga heap(1,2)"  desc=700000000055210
HEAP DUMP heap name="sga heap(1,3)"  desc=700000000056a68
HEAP DUMP heap name="sga heap(2,0)"  desc=70000000005ba28
HEAP DUMP heap name="sga heap(2,1)"  desc=70000000005d280
HEAP DUMP heap name="sga heap(2,2)"  desc=70000000005ead8
HEAP DUMP heap name="sga heap(2,3)"  desc=700000000060330
HEAP DUMP heap name="sga heap(3,0)"  desc=7000000000652f0
HEAP DUMP heap name="sga heap(3,1)"  desc=700000000066b48
HEAP DUMP heap name="sga heap(3,2)"  desc=7000000000683a0
HEAP DUMP heap name="sga heap(3,3)"  desc=700000000069bf8