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Title: 16.Data segment header block(no freelist groups)  •  Size: 266029  •  Last Modified: Thu, 04 Feb 2010 15:48:32 GMT
16 DATA SEGMENT HEADER - UNLIMITED
 
  0 1 2 3 4 5 6 7 8 9 A B C D E F   Start dump data blocks tsn: 16 file#: 15 minblk 33 maxblk 33
00 101 022 003 004 21 00 C0 035 F1 1B 95 00 00 006 017 048   buffer tsn: 16 rdba: 0x03c00021 (15/33)
10 1E 299 00 0010 00 00 00 0011 00 00 00 0012 D9 05 C0 0313   HEADER scn: 0x0000.00951bf1 seq: 0x01 flg: 0x04 tail: 0x1bf11001
20 01 00 00 0014 C5 00 00 0015 26 06 00 0016 20 0417 00 00   frmt: 0x02 chkval: 0x291e type: 0x10=DATA SEGMENT HEADER - UNLIMITED
30 C4 00 00 0018 08 00 00 0019 08 00 00 0020 D9 09 C0 0321   HWM  
40 D9 05 C0 0322 4B 00 00 0023 26 06 00 0024 26 06 00 0025   Extent Control Header
50 00 00 00 00 00 00 00 00 00 00 00 00 79 00 00 0026   Map Header -----------------------------------------------------------------
60 E9 03 C0 0327 B9 7A 00 0028 00 00 00 4029 22 00 C0 0330   Extent Header:: spare1: 0 spare2: 0 #extents: 197 #blocks: 1574
70 07 00 00 0031 51 00 C0 03 08 00 00 00 59 00 C0 03   last map 0x03c005d9 #maps: 1 offset: 1056
80 08 00 00 00 69 00 C0 03 08 00 00 00 71 00 C0 03   Highwater:: 0x03c009d9 ext#: 196 blk#: 8 ext size: 8
90 08 00 00 00 81 00 C0 03 08 00 00 00 89 00 C0 03  
A0 08 00 00 00 99 00 C0 03 08 00 00 00 A1 00 C0 03   #blocks below: 1574
B0 08 00 00 00 A9 00 C0 03 08 00 00 00 B9 00 C0 03   mapblk 0x03c005d9 offset: 75
C0 08 00 00 00 C1 00 C0 03 08 00 00 00 D1 00 C0 03   Unlocked
D0 08 00 00 00 D9 00 C0 03 08 00 00 00 E1 00 C0 03   Map Header:: next 0x03c005d9 #extents: 121 obj#: 31417 flag: 0x40000000
E0 08 00 00 00 F1 00 C0 03 08 00 00 00 F9 00 C0 03   Extent Map
F0 08 00 00 00 01 01 C0 03 08 00 00 00 11 01 C0 03   -----------------------------------------------------------------
100 08 00 00 00 19 01 C0 03 08 00 00 00 29 01 C0 03   0x03c00022 length: 7
110 08 00 00 00 31 01 C0 03 08 00 00 00 39 01 C0 03   0x03c00051 length: 8
120 08 00 00 00 49 01 C0 03 08 00 00 00 51 01 C0 03   0x03c00059 length: 8
130 08 00 00 00 61 01 C0 03 08 00 00 00 69 01 C0 03   0x03c00069 length: 8
140 08 00 00 00 71 01 C0 03 08 00 00 00 81 01 C0 03   Extent Map 0x03c00071 length: 8
150 08 00 00 00 89 01 C0 03 08 00 00 00 99 01 C0 03   0x03c00081 length: 8
160 08 00 00 00 A1 01 C0 03 08 00 00 00 A9 01 C0 03   0x03c00089 length: 8
170 08 00 00 00 B9 01 C0 03 08 00 00 00 C1 01 C0 03   0x03c00099 length: 8
180 08 00 00 00 D1 01 C0 03 08 00 00 00 D9 01 C0 03   0x03c000a1 length: 8
190 08 00 00 00 E1 01 C0 03 08 00 00 00 F1 01 C0 03   0x03c000a9 length: 8
1A0 08 00 00 00 F9 01 C0 03 08 00 00 00 01 02 C0 03   0x03c000b9 length: 8
1B0 08 00 00 00 11 02 C0 03 08 00 00 00 19 02 C0 03   0x03c000c1 length: 8
1C0 08 00 00 00 21 02 C0 03 08 00 00 00 31 02 C0 03   0x03c000d1 length: 8
1D0 08 00 00 00 39 02 C0 03 08 00 00 00 49 02 C0 03   0x03c000d9 length: 8
1E0 08 00 00 00 51 02 C0 03 08 00 00 00 59 02 C0 03   0x03c000e1 length: 8
1F0 08 00 00 00 69 02 C0 03 08 00 00 00 71 02 C0 03   0x03c000f1 length: 8
200 08 00 00 00 79 02 C0 03 08 00 00 00 89 02 C0 03   0x03c000f9 length: 8
210 08 00 00 00 91 02 C0 03 08 00 00 00 99 02 C0 03   0x03c00101 length: 8
220 08 00 00 00 A9 02 C0 03 08 00 00 00 B1 02 C0 03   0x03c00111 length: 8
230 08 00 00 00 B9 02 C0 03 08 00 00 00 C9 02 C0 03   0x03c00119 length: 8
240 08 00 00 00 D1 02 C0 03 08 00 00 00 D9 02 C0 03   0x03c00129 length: 8
250 08 00 00 00 E1 02 C0 03 08 00 00 00 F1 02 C0 03   0x03c00131 length: 8
260 08 00 00 00 F9 02 C0 03 08 00 00 00 01 03 C0 03   0x03c00139 length: 8
270 08 00 00 00 11 03 C0 03 08 00 00 00 19 03 C0 03   0x03c00149 length: 8
280 08 00 00 00 21 03 C0 03 08 00 00 00 31 03 C0 03   0x03c00151 length: 8
290 08 00 00 00 39 03 C0 03 08 00 00 00 49 03 C0 03   0x03c00161 length: 8
2A0 08 00 00 00 51 03 C0 03 08 00 00 00 59 03 C0 03   0x03c00169 length: 8
2B0 08 00 00 00 69 03 C0 03 08 00 00 00 71 03 C0 03   0x03c00171 length: 8
2C0 08 00 00 00 79 03 C0 03 08 00 00 00 89 03 C0 03   0x03c00181 length: 8
2D0 08 00 00 00 91 03 C0 03 08 00 00 00 A1 03 C0 03   0x03c00189 length: 8
2E0 08 00 00 00 A9 03 C0 03 08 00 00 00 B1 03 C0 03   0x03c00199 length: 8
2F0 08 00 00 00 C1 03 C0 03 08 00 00 00 C9 03 C0 03   0x03c001a1 length: 8
300 08 00 00 00 D9 03 C0 03 08 00 00 00 E1 03 C0 03   0x03c001a9 length: 8
310 08 00 00 00 E9 03 C0 03 08 00 00 00 F9 03 C0 03   0x03c001b9 length: 8
320 08 00 00 00 01 04 C0 03 08 00 00 00 09 04 C0 03   0x03c001c1 length: 8
330 08 00 00 00 19 04 C0 03 08 00 00 00 21 04 C0 03   0x03c001d1 length: 8
340 08 00 00 00 31 04 C0 03 08 00 00 00 41 04 C0 03   0x03c001d9 length: 8
350 08 00 00 00 49 04 C0 03 08 00 00 00 59 04 C0 03   0x03c001e1 length: 8
360 08 00 00 00 69 04 C0 03 08 00 00 00 79 04 C0 03   0x03c001f1 length: 8
370 08 00 00 00 89 04 C0 03 08 00 00 00 91 04 C0 03   0x03c001f9 length: 8
380 08 00 00 00 A1 04 C0 03 08 00 00 00 B1 04 C0 03   0x03c00201 length: 8
390 08 00 00 00 C1 04 C0 03 08 00 00 00 D1 04 C0 03   0x03c00211 length: 8
3A0 08 00 00 00 D9 04 C0 03 08 00 00 00 E9 04 C0 03   0x03c00219 length: 8
3B0 08 00 00 00 F9 04 C0 03 08 00 00 00 09 05 C0 03   0x03c00221 length: 8
3C0 08 00 00 00 11 05 C0 03 08 00 00 00 21 05 C0 03   0x03c00231 length: 8
3D0 08 00 00 00 31 05 C0 03 08 00 00 00 41 05 C0 03   0x03c00239 length: 8
3E0 08 00 00 00 49 05 C0 03 08 00 00 00 59 05 C0 03   0x03c00249 length: 8
3F0 08 00 00 00 69 05 C0 03 08 00 00 00 79 05 C0 03   0x03c00251 length: 8
400 08 00 00 00 81 05 C0 03 08 00 00 00 91 05 C0 03   0x03c00259 length: 8
410 08 00 00 00 A1 05 C0 03 08 00 00 00 B1 05 C0 03   0x03c00269 length: 8
420 08 00 00 00 B9 05 C0 03 08 00 00 00 C9 05 C0 0332   0x03c00271 length: 8
430 08 00 00 0033 0234 0035 01 0036 01 0037 0138 00 0139 00 00 00   0x03c00279 length: 8
440 00 00 00 00 8E 01 00 0040 22 00 C0 0341 55 00 C0 0342   Freelists 0x03c00289 length: 8
450 0143 00 00 00 0244 00 09 00 E6 1F 00 00 D5 09 C0 0345   0x03c00291 length: 8
460 56 00 C0 0346 0147 00 00 00 0148 00 12 00 E8 1F 00 00   0x03c00299 length: 8
470 27 00 C0 0349 23 00 C0 0350 00 00 00 00 00 00 00 00   0x03c002a9 length: 8
480 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002b1 length: 8
490 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002b9 length: 8
4A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002c9 length: 8
4B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002d1 length: 8
4C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002d9 length: 8
4D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002e1 length: 8
4E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002f1 length: 8
4F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c002f9 length: 8
500 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00301 length: 8
510 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00311 length: 8
520 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00319 length: 8
530 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00321 length: 8
540 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00331 length: 8
550 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00339 length: 8
560 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00349 length: 8
570 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00351 length: 8
580 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00359 length: 8
590 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00369 length: 8
5A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00371 length: 8
5B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00379 length: 8
5C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00389 length: 8
5D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00391 length: 8
5E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003a1 length: 8
5F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003a9 length: 8
600 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003b1 length: 8
610 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003c1 length: 8
620 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003c9 length: 8
630 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003d9 length: 8
640 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003e1 length: 8
650 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003e9 length: 8
660 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c003f9 length: 8
670 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00401 length: 8
680 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00409 length: 8
690 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00419 length: 8
6A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00421 length: 8
6B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00431 length: 8
6C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00441 length: 8
6D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00449 length: 8
6E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00459 length: 8
6F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00469 length: 8
700 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00479 length: 8
710 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00489 length: 8
720 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00491 length: 8
730 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004a1 length: 8
740 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004b1 length: 8
750 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004c1 length: 8
760 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004d1 length: 8
770 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004d9 length: 8
780 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004e9 length: 8
790 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c004f9 length: 8
7A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00509 length: 8
7B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00511 length: 8
7C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00521 length: 8
7D0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00531 length: 8
7E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   0x03c00541 length: 8
7F0 00 00 00 00 00 00 00 00 00 00 00 00 01 10 F1 1B51   0x03c00549 length: 8
0x03c00559 length: 8
0x03c00569 length: 8
0x03c00579 length: 8
0x03c00581 length: 8
0x03c00591 length: 8
0x03c005a1 length: 8
0x03c005b1 length: 8
0x03c005b9 length: 8
0x03c005c9 length: 8
nfl = 1, nfb = 1 typ = 1 nxf = 2 ccnt = 398
SEG LST:: flg: USED lhd: 0x03c00022 ltl: 0x03c00055
XCT LST:: flg: USED lhd: 0x03c009d5 ltl: 0x03c00056 xid: 0x0002.009.00001fe6
XCT LST:: flg: USED lhd: 0x03c00027 ltl: 0x03c00023 xid: 0x0001.012.00001fe8

1
Block types.
type:0x10
2
The format of the cache header was changed for Oracle8. Under Oracle8 and 9, the value is always 2. Previously, it was 1.
frmt:0x02
3
spare1
4
spare2
5
The tablespace relative database block address (RDBA). This is constructed from the tablespace relative file number (10 bits), and the block number of the data block within that file (22 bits) RDBA: 0x03C00021
6
The SCN at which the block was last changed. The low-order 4 bytes are called the SCN base, and the high-order 2 bytes are called the SCN wrap.
scn: 0x0000.00951BF1
7
A sequence number incremented for each change to a block at the same SCN. If the sequence number wraps, a new SCN must
be allocated. The value 0xff is reserved. When present it indicates that the block has been marked as corrupt by Oracle.
seq:0x01

8
Flag.
1 - virgin block
2 - last change to the block was for a cleanout operation
4 - checksum value is set
8 - temporary data
flg:0x04
9
An optional checksum of the block contents. When a block is written, the checksum is either cleared or set depending on the
setting of the db_block_checksum parameter. When a block is read, the checksum is verified if present and if the parameter is set
to TRUE. Checksums are always calculated and checked for blocks in the SYSTEM tablespace. The checksum is the XOR of all the
other 2-byte pairs in the block. Thus when a block with a checksum is checked, the XOR of all the 2-byte words in the block should be 0.
chkval:0x291E
10
spare3
11
spare1
12
spare2
13
RDBA of the last block of the extent map: 0x03C005D9
14
No. of maps.
#maps: 1

15
Number of extents.
#extents:197
16
Number of blocks.
#blocks:1574
17
Freelists start offset.
offset: 1056

18
High water mark (HWM).
Highwater: extent no.
ext#: 196
19
High water mark (HWM) .
Highwater: block no. blk#: 8
20
High water mark (HWM).
Highwater: extent size:8
21
High water mark (HWM) is the pointer to the DBA of the last block to receive inserts. Blocks below this mark are maintained on free lists. Blocks
in extents above this mark have been allocated to the segment but haven't been used yet. Blocks above the HWM are available for SQL*Loader
direct-load operations, parallel DML, and for inserts after the free list has been exhausted and the HWM has been moved.
Highwater: RDBA: 0x03C009D9 => file- 15 block- 2521
22
Map block RDBA.
mapblk: 0x62916057
23
Offset:75
24
#blocks in seg. hdr's freelists:1574
25
#blocks below:1574
26
Number of extents in extent map.
Map Header: #extents:121

27
Contains DBA information of the next block containing extent map information
Map Header:next 0x:03C003E9
28
Map Header: obj#:31417
29
Map Header: flag: 0x:40000000
30
Beginning RDBA :
RDBA (extent#): 0x03C00022
31
Number of blocks associated with the extent
len : 7
32
RDBA (extent#): 0x03C005C9
33
len : 8
34
Freelists.
35
Number of transaction frelists.
nxf:2
36
Number of segment freelists.
nfl:1
37
Number of freelist blocks.
nfb:1
38
typ = 1
39
flg: USED
40
ccnt = 398
41
Segment freelist: first block
lhd: 0x03c00022

42
Segment freelist: last block
ltl: 0x03c00055
43
Transaction Freelists:
flg: USED
44
Transaction freelist: XID ( the pointer to the rollback segment transaction table slot - Undoseg#.slot#.wrap)
The Undoseg# is the rollback segment, the slot# refers to a slot in trunsaction table, and wrap refers to the number of
times that the slot has been used in a trunsaction.
xid: 0x0002.009.00001fe6
45
Transaction freelist: first block.
lhd: 0x03c009d5

46
Transaction freelist: last block.
ltl: 0x03c00056
47
flg: USED
48
xid: 0x0001.012.00001fe8
49
Transaction freelist: first block.
lhd: 0x03c00027

50
Transaction freelist: last block.
ltl: 0x03c00023
51
Tail is comprised of the low-order two bytes of the SCN base followed by the block type and the sequence number. The consistency of the header and
tail is checked whenever a block is read. This detects most block corruptions, in particular split blocks from hot backups.
tail:0x1BF11001