max_cr_dba이란 무엇인가? what is max_cr_dba(max length)

1. Ver.2
(2016.07.19)

2. © Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Scenario
Buffer Cache
XCURRENT
col 1: [ 1] 41 (A)
BH
(0x657d8238)
B
A
C
D
E
F
G
H
I
Update; Commit
Update;Commit
BCDEFGHI
When update a value ‘A’ with values ‘B’ to ‘I’ consecutively,
How are CU blocks and CR blocks allocated inside the Buffer Cache?

3. © Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Expected outcome
Buffer Cache
CURRENT
BLOCK
(XCUR)
Update
S1
Consistent Read
Block
(CR 1)&
UNDO
Update
S2
Consistent Read
Block
(CR 2)&
UNDO
Update
S3
Consistent Read
Block
(CR 3)&
UNDO
Update
S4
Consistent Read
Block
(CR 4)&
UNDO
Update
S5
Consistent Read
Block
(CR 5)&
UNDO
Update
S6

4. © Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
2013, Oracle 10g Performance: chapter 06 buffer cache 25,26 page, Kyle Hailey
Cited from http://www.slideshare.net/khailey/oracle-10g-performance-chapter-06-buffer-cache
It's so difficult to understand
only through the book.
I'd like to check internal
actual situation of oracle
with my own eyes
“Max length in Cache Buffer”mechanism as explained in Kyle Hailey's presentation
1. UPDATE T1 SET C2= 'B' ; COMMIT ;
2. UPDATE T1 SET C2= 'C' ; COMMIT ;
3. UPDATE T1 SET C2= 'D' ; COMMIT ;
. . . . . .
9. UPDATE T1 SET C2= 'G' ; COMMIT ;
. . . . . . ?

5. © Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Inside of Oracle via ODI Analyzer When _db_block_max_cr_dba = 6
Buffer Cache
CR
col 1: [ 1] 41
(A)
BH (0x657d8238)
CR
col 1: [ 1] 42
(B)
BH (0x657d8100)
CR
col 1: [ 1] 43
(C)
BH (0x653fab88)
CR
col 1: [ 1] 44
(D)
BH (0x653fa7e0)
CR
col 1: [ 1] 45 (E)
BH (0x653fa438)
CR
col 1: [ 1] 46 (F)
BH (0x653fa090)
New CU
block
New CU block
New CU
Block
XCURRENT
XCURRENTXCURRENT
XCURRENT
XCURRENT
New CU
Block
XCURRENT
col 1: [ 1] 49
(I)
XCURRENT
block
1
block
2
block
3
block
4
block
5
block
6
block
1
block
2
block
3
New CU
block
XCURRENT
col 1: [ 1] 47
(G)
CR
col 1: [ 1] 47
(G)
XCURRENT
col 1: [ 1] 48
(H)
CR
col 1: [ 1] 48
(H)
CR Block Reuse
CR Block Reuse
CR Block Reuse
Oracle init parameter
When _db_block_max_cr_dba = 6

6. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
1. UPDATE T1 SET C2= ' B ' ; COMMIT ;
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
2
“A”
“B”
“A”
UPDATE T1
SET c2 = ‘B’

7. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
2. UPDATE SYSTEM.T1 SET C2= ' C ' ; COMMIT ;
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
“A”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
“A”
UPDATE T1
SET c2 = ‘C’
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”

8. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
3. UPDATE SYSTEM.T1 SET C2= ' D ' ; COMMIT ;
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
“A”
“A”
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
BH (0x653fa570) file#: 6 rdba: 0x01800082 (6/130) class: 18 ba:
0x653bc000
xid: 0x0001.000.000009ef seq: 0x352
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 43
“C”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
BH (0x653fa7e0) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c0000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 ---- 1 fsc 0x0000.00000000
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 44
4
“D”
UPDATE T1
SET c2 = ‘D’

9. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
4. UPDATE SYSTEM.T1 SET C2= ' E ' ; COMMIT ;
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
“A”
“A”
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
BH (0x653fa570) file#: 6 rdba: 0x01800082 (6/130) class: 18 ba:
0x653bc000
xid: 0x0001.000.000009ef seq: 0x352
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 43
“C”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”
BH (0x653fa1c8) file#: 6 rdba: 0x01800112 (6/274) class: 104 ba:
0x653b6000
xid: 0x002c.001.000000c4 seq: 0x69
* Rec #0x11 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 44
“D”
BH (0x653fa7e0) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c0000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 ---- 1 fsc 0x0000.00000000
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 44
4
“D”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
BH (0x653fa438) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653ba000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 ---- 1 fsc 0x0000.00000000
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 45
5
“E”
UPDATE T1
SET c2 = ‘E’

10. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
5. UPDATE SYSTEM.T1 SET C2= ' F ' ; COMMIT ;
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
“A”
“A”
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
BH (0x653fa570) file#: 6 rdba: 0x01800082 (6/130) class: 18 ba:
0x653bc000
xid: 0x0001.000.000009ef seq: 0x352
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 43
“C”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”
BH (0x653fa1c8) file#: 6 rdba: 0x01800112 (6/274) class: 104 ba:
0x653b6000
xid: 0x002c.001.000000c4 seq: 0x69
* Rec #0x11 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 44
“D”
BH (0x653f9e20) file#: 6 rdba: 0x01800102 (6/258) class: 102 ba:
0x653b0000
xid: 0x002b.001.000000c6 seq: 0x62
* Rec #0x2 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 45
“E”
BH (0x653fa7e0) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c0000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 ---- 1 fsc 0x0000.00000000
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 44
4
“D”
BH (0x653fa438) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653ba000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 --U- 1 fsc 0x0000.0021a127
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 45
5
“E”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
BH (0x653fa090) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653b4000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 46
6
“F”
UPDATE T1
SET c2 = ‘F’

11. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
“A”
6. UPDATE SYSTEM.T1 SET C2= ' G ' ; COMMIT ; Reuse BH ‘8283’
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x002a.001.000000c6 0x018000f2.0062.03 --U- 1 fsc 0x0000.0021a12d
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 C--- 0 scn 0x0000.0021a12a
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 47
1
“G”
“A”
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
BH (0x653fa570) file#: 6 rdba: 0x01800082 (6/130) class: 18 ba:
0x653bc000
xid: 0x0001.000.000009ef seq: 0x352
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 43
“C”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”
BH (0x653fa1c8) file#: 6 rdba: 0x01800112 (6/274) class: 104 ba:
0x653b6000
xid: 0x002c.001.000000c4 seq: 0x69
* Rec #0x11 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 44
“D”
BH (0x653f9e20) file#: 6 rdba: 0x01800102 (6/258) class: 102 ba:
0x653b0000
xid: 0x002b.001.000000c6 seq: 0x62
* Rec #0x2 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 45
“E”
BH (0x653fa7e0) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c0000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 ---- 1 fsc 0x0000.00000000
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 44
4
“D”
BH (0x653f9bb0) file#: 6 rdba: 0x018000f2 (6/242) class: 100 ba:
0x653ac000
xid: 0x002a.001.000000c6 seq: 0x62
* Rec #0x3 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 46
“F”
BH (0x653fa438) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653ba000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 --U- 1 fsc 0x0000.0021a127
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 45
5
“E”
BH (0x653fa090) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653b4000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 46
6
“F”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
UPDATE T1
SET c2 = ‘G’

12. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
“A”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
7. UPDATE SYSTEM.T1 SET C2= ' H ' ; COMMIT ; Reuse BH ‘8100’
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
“A”
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
sst: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x002a.001.000000c6 0x018000f2.0062.03 C--- 0 scn 0x0000.0021a12d
0x02 0x0029.001.00000107 0x018000e2.00bc.04 --U- 1 fsc 0x0000.0021a130
0x03 0x002b.001.000000c6 0x01800102.0062.02 C--- 0 scn 0x0000.0021a12a
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 48
2
“H”
BH (0x653fa570) file#: 6 rdba: 0x01800082 (6/130) class: 18 ba:
0x653bc000
xid: 0x0001.000.000009ef seq: 0x352
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 43
“C”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”
BH (0x653fa1c8) file#: 6 rdba: 0x01800112 (6/274) class: 104 ba:
0x653b6000
xid: 0x002c.001.000000c4 seq: 0x69
* Rec #0x11 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 44
“D”
BH (0x653f9e20) file#: 6 rdba: 0x01800102 (6/258) class: 102 ba:
0x653b0000
xid: 0x002b.001.000000c6 seq: 0x62
* Rec #0x2 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 45
“E”
BH (0x653fa7e0) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c0000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 ---- 1 fsc 0x0000.00000000
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 44
4
“D”
BH (0x653f9bb0) file#: 6 rdba: 0x018000f2 (6/242) class: 100 ba:
0x653ac000
xid: 0x002a.001.000000c6 seq: 0x62
* Rec #0x3 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 46
“F”
BH (0x653fa438) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653ba000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 --U- 1 fsc 0x0000.0021a127
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 45
5
“E”
BH (0x653fa090) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653b4000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 46
6
“F”
BH (0x653f9940) file#: 6 rdba: 0x018000e2 (6/226) class: 98 ba:
0x653a8000
xid: 0x0029.001.00000107 seq: 0xbc
* Rec #0x4 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 47
“G”
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x002a.001.000000c6 0x018000f2.0062.03 --U- 1 fsc 0x0000.0021a12d
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 C--- 0 scn 0x0000.0021a12a
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 47
1
“G”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
UPDATE T1
SET c2 = ‘H’

13. Buffer Cache
© Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Undo Segment
Data Block
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
1
“A”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 ---- 1 fsc 0x0000.00000000
0x03 0x0000.000.00000000 0x00000000.0000.00 ---- 0 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 42
2
“B”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0027.000.000000c4 0x00000000.0000.00 C--- 0 scn 0x0000.0021a110
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 43
3
“C”
8. UPDATE SYSTEM.T1 SET C2= ' I ' ; COMMIT ; Reuse BH‘ab88’
Rows
block_row_dump:
tab 0, row 0, @0x1f70
tl: 16 fb: --H-FL-- lb: 0x0 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 41
“A”
BH (0x657d7e90) file#: 6 rdba: 0x018000a2 (6/162) class: 90 ba:
0x65434000
xid: 0x0025.000.00000138 seq: 0x9b
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 41
“A”
BH (0x653fa918) file#: 6 rdba: 0x01800092 (6/146) class: 86 ba:
0x653c2000
xid: 0x0023.000.00000132 seq: 0xa2
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 42
“B”
BH (0x653fa570) file#: 6 rdba: 0x01800082 (6/130) class: 18 ba:
0x653bc000
xid: 0x0001.000.000009ef seq: 0x352
* Rec #0x1 slt: 0x00 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 43
“C”
BH (0x653fab88) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c6000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x002a.001.000000c6 0x018000f2.0062.03 C--- 0 scn 0x0000.0021a12d
0x02 0x0029.001.00000107 0x018000e2.00bc.04 C--- 0 scn 0x0000.0021a130
0x03 0x0028.004.000000db 0x018000d3.00b2.08 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 49
3
“I”
BH (0x653fa1c8) file#: 6 rdba: 0x01800112 (6/274) class: 104 ba:
0x653b6000
xid: 0x002c.001.000000c4 seq: 0x69
* Rec #0x11 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 44
“D”
BH (0x653f9e20) file#: 6 rdba: 0x01800102 (6/258) class: 102 ba:
0x653b0000
xid: 0x002b.001.000000c6 seq: 0x62
* Rec #0x2 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 45
“E”
BH (0x653fa7e0) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653c0000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 ---- 1 fsc 0x0000.00000000
0x02 0x0025.000.00000138 0x018000a2.009b.01 C--- 0 scn 0x0000.0021a11e
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 44
4
“D”
BH (0x653f9bb0) file#: 6 rdba: 0x018000f2 (6/242) class: 100 ba:
0x653ac000
xid: 0x002a.001.000000c6 seq: 0x62
* Rec #0x3 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 46
“F”
BH (0x653fa438) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653ba000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 --U- 1 fsc 0x0000.0021a127
0x03 0x0023.000.00000132 0x01800092.00a2.01 C--- 0 scn 0x0000.0021a121
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 45
5
“E”
BH (0x653fa090) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x653b4000
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0001.000.000009ef 0x01800082.0352.01 C--- 0 scn 0x0000.0021a124
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 ---- 1 fsc 0x0000.00000000
tl: 16 fb: --H-FL-- lb: 0x3 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 46
6
“F”
BH (0x653f9940) file#: 6 rdba: 0x018000e2 (6/226) class: 98 ba:
0x653a8000
xid: 0x0029.001.00000107 seq: 0xbc
* Rec #0x4 slt: 0x01 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 47
“G”
BH (0x657d8238) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x6543a000
st: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x002a.001.000000c6 0x018000f2.0062.03 --U- 1 fsc 0x0000.0021a12d
0x02 0x002c.001.000000c4 0x01800112.0069.11 C--- 0 scn 0x0000.0021a127
0x03 0x002b.001.000000c6 0x01800102.0062.02 C--- 0 scn 0x0000.0021a12a
tl: 16 fb: --H-FL-- lb: 0x1 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 47
1
“G”
BH (0x653f96d0) file#: 6 rdba: 0x018000d3 (6/211) class: 96 ba:
0x653a4000
xid: 0x0028.004.000000db seq: 0xb2
* Rec #0x8 slt: 0x04 objn: 69880(0x000110f8)
* Layer: 11 (Row) opc: 1 rci 0x00
col 1: [ 1] 48
“H”
BH (0x657d8100) file#: 5 rdba: 0x0140dcab (5/56491) class: 1 ba: 0x65438000
sst: XCURRENT md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x002a.001.000000c6 0x018000f2.0062.03 C--- 0 scn 0x0000.0021a12d
0x02 0x0029.001.00000107 0x018000e2.00bc.04 --U- 1 fsc 0x0000.0021a130
0x03 0x002b.001.000000c6 0x01800102.0062.02 C--- 0 scn 0x0000.0021a12a
tl: 16 fb: --H-FL-- lb: 0x2 cc: 2
col 0: [10] 31 20 20 20 20 20 20 20 20 20
col 1: [ 1] 48
2
“H”
st: CR md: NULL fpin: 'kdswh11: kdst_fetch' tch: 1
UPDATE T1
SET c2 = ‘I’

14. © Copyrights 2001~2016, EXEM CO.,LTD. All Rights Reserved.
Inside of Oracle via ODI tool When _db_block_max_cr_dba = 6
Buffer Cache
CR
col 1: [ 1] 41
(A)
BH (0x657d8238)
CR
col 1: [ 1] 42
(B)
BH (0x657d8100)
CR
col 1: [ 1] 43
(C)
BH (0x653fab88)
CR
col 1: [ 1] 44
(D)
BH (0x653fa7e0)
CR
col 1: [ 1] 45 (E)
BH (0x653fa438)
CR
col 1: [ 1] 46 (F)
BH (0x653fa090)
New CU
block
New CU block
New CU
Block
XCURRENT
XCURRENTXCURRENT
XCURRENT
XCURRENT
New CU
Block
XCURRENT
col 1: [ 1] 49
(I)
XCURRENT
CR Block Reuse
CR Block Reuse
bloc
k1
bloc
k2
bloc
k3
block
4
block
5
block
6
block
1
block
2
block
3
New CU
block
CR Block Reuse
XCURRENT
col 1: [ 1] 47
(G)
CR
col 1: [ 1] 47
(G)
XCURRENT
col 1: [ 1] 48
(H)
CR
col 1: [ 1] 48
(H)
When _db_block_max_cr_dba equals 6,
a maximum of 6 data blocks are allocated
and rotate among them for updates.

15. Oracle Deep Internal
Blog
Video
E-mail
NAVER http://cafe.naver.com/playexem
ITPUB http://blog.itpub.net/31135309/
Wordpress https://playexem.wordpress.com/
Slideshare http://www.slideshare.net/playexem
Youtube https://www.youtube.com/channel/UC
5wKR_-A0eL_Pn_EMzoauJg
Research & Contents Team Sook jin, Kim
edu@ex-em.com
For more information, or to schedule an on-site
education, contact via blog or e-mail