Sundaramurthy Blog

June 15, 2010

Data file first block structure (DBA 4,1)

Filed under: Oracle Block,Oracle internals — sundar5 @ 6:32 pm

When you create any tablespace in the oracle environment, it reserves the first block of a data file for an  internal purpose. All information related to checkpoint, recovery status, SCN etc. are kept in the first block.  When you open the database, oracle always validates  the control file information with the first block of data files. Below is the structure of the first block.

Data file internal structure dba 4,1
UNIT       NAME OFFSET VALUE
struct kcvfh, 676 bytes @0
struct kcvfhbfh, 20 bytes @0
ub1 type_kcbh @0 0x0b
ub1 frmt_kcbh @1 0xa2
ub1 spare1_kcbh @2 0x00
ub1 spare2_kcbh @3 0x00
ub4 rdba_kcbh @4 0x01000001
ub4 bas_kcbh @8 0x00000000
ub2 wrp_kcbh @12 0x0000
ub1 seq_kcbh @14 0x01
ub1 flg_kcbh @15 0x04 (KCBHFCKV)
ub2 chkval_kcbh @16 0x8412
ub2 spare3_kcbh @18 0x0000
struct kcvfhhdr, 76 bytes @20
ub4 kccfhswv @20 0x00000000
ub4 kccfhcvn @24 0x0a200000
ub4 kccfhdbi @28 0x43f4c8dc
text kccfhdbn[0] @32 E
text kccfhdbn[1] @33 T
text kccfhdbn[2] @34 L
text kccfhdbn[3] @35 T
text kccfhdbn[4] @36 E
text kccfhdbn[5] @37 S
text kccfhdbn[6] @38 T
text kccfhdbn[7] @39
ub4 kccfhcsq @40 0x00000192
ub4 kccfhfsz @44 0x00006400
s_blkz kccfhbsz @48 0x00
ub2 kccfhfno @52 0x0004
ub2 kccfhtyp @54 0x0003
ub4 kccfhacid @56 0x00000000
ub4 kccfhcks @60 0x00000000
text kccfhtag[0] @64
text kccfhtag[1] @65
text kccfhtag[2] @66
text kccfhtag[3] @67
text kccfhtag[4] @68
text kccfhtag[5] @69
text kccfhtag[6] @70
text kccfhtag[7] @71
text kccfhtag[8] @72
text kccfhtag[9] @73
text kccfhtag[10] @74
text kccfhtag[11] @75
text kccfhtag[12] @76
text kccfhtag[13] @77
text kccfhtag[14] @78
text kccfhtag[15] @79
text kccfhtag[16] @80
text kccfhtag[17] @81
text kccfhtag[18] @82
text kccfhtag[19] @83
text kccfhtag[20] @84
text kccfhtag[21] @85
text kccfhtag[22] @86
text kccfhtag[23] @87
text kccfhtag[24] @88
text kccfhtag[25] @89
text kccfhtag[26] @90
text kccfhtag[27] @91
text kccfhtag[28] @92
text kccfhtag[29] @93
text kccfhtag[30] @94
text kccfhtag[31] @95
ub4 kcvfhrdb @96 0x00000000
struct kcvfhcrs, 8 bytes @100
ub4 kscnbas @100 0x0002a4da
ub2 kscnwrp @104 0x0000
ub4 kcvfhcrt @108 0x2ae967a3
ub4 kcvfhrlc @112 0x2ae9645c
struct kcvfhrls, 8 bytes @116
ub4 kscnbas @116 0x00000001
ub2 kscnwrp @120 0x0000
ub4 kcvfhbti @124 0x00000000
struct kcvfhbsc, 8 bytes @128
ub4 kscnbas @128 0x00000000
ub2 kscnwrp @132 0x0000
ub2 kcvfhbth @136 0x0000
ub2 kcvfhsta @138 0x0004 (KCVFHOFZ)
struct kcvfhckp, 36 bytes @484
struct kcvcpscn, 8 bytes @484
ub4 kscnbas @484 0x000cb354
ub2 kscnwrp @488 0x0000
ub4 kcvcptim @492 0x2b0044ee
ub2 kcvcpthr @496 0x0001
union u, 12 bytes @500
struct kcvcprba, 12 bytes @500
ub4 kcrbaseq @500 0x0000000a
ub4 kcrbabno @504 0x00000002
ub2 kcrbabof @508 0x0010
ub1 kcvcpetb[0] @512 0x02
ub1 kcvcpetb[1] @513 0x00
ub1 kcvcpetb[2] @514 0x00
ub1 kcvcpetb[3] @515 0x00
ub1 kcvcpetb[4] @516 0x00
ub1 kcvcpetb[5] @517 0x00
ub1 kcvcpetb[6] @518 0x00
ub1 kcvcpetb[7] @519 0x00
ub4 kcvfhcpc @140 0x00000010
ub4 kcvfhrts @144 0x00000000
ub4 kcvfhccc @148 0x0000000f
struct kcvfhbcp, 36 bytes @152
struct kcvcpscn, 8 bytes @152
ub4 kscnbas @152 0x00000000
ub2 kscnwrp @156 0x0000
ub4 kcvcptim @160 0x00000000
ub2 kcvcpthr @164 0x0000
union u, 12 bytes @168
struct kcvcprba, 12 bytes @168
ub4 kcrbaseq @168 0x00000000
ub4 kcrbabno @172 0x00000000
ub2 kcrbabof @176 0x0000
ub1 kcvcpetb[0] @180 0x00
ub1 kcvcpetb[1] @181 0x00
ub1 kcvcpetb[2] @182 0x00
ub1 kcvcpetb[3] @183 0x00
ub1 kcvcpetb[4] @184 0x00
ub1 kcvcpetb[5] @185 0x00
ub1 kcvcpetb[6] @186 0x00
ub1 kcvcpetb[7] @187 0x00
ub4 kcvfhbhz @312 0x00000000
struct kcvfhxcd, 16 bytes @316
ub4 space_kcvmxcd[0] @316 0x00000000
ub4 space_kcvmxcd[1] @320 0x00000000
ub4 space_kcvmxcd[2] @324 0x00000000
ub4 space_kcvmxcd[3] @328 0x00000000
word kcvfhtsn @332 4
ub2 kcvfhtln @336 0x000d
text kcvfhtnm[0] @338 P
text kcvfhtnm[1] @339 O
text kcvfhtnm[2] @340 C
text kcvfhtnm[3] @341 T
text kcvfhtnm[4] @342 A
text kcvfhtnm[5] @343 B
text kcvfhtnm[6] @344 L
text kcvfhtnm[7] @345 E
text kcvfhtnm[8] @346 S
text kcvfhtnm[9] @347 P
text kcvfhtnm[10] @348 A
text kcvfhtnm[11] @349 C
text kcvfhtnm[12] @350 E
text kcvfhtnm[13] @351
text kcvfhtnm[14] @352
text kcvfhtnm[15] @353
text kcvfhtnm[16] @354
text kcvfhtnm[17] @355
text kcvfhtnm[18] @356
text kcvfhtnm[19] @357
text kcvfhtnm[20] @358
text kcvfhtnm[21] @359
text kcvfhtnm[22] @360
text kcvfhtnm[23] @361
text kcvfhtnm[24] @362
text kcvfhtnm[25] @363
text kcvfhtnm[26] @364
text kcvfhtnm[27] @365
text kcvfhtnm[28] @366
text kcvfhtnm[29] @367
ub4 kcvfhrfn @368 0x00000004
struct kcvfhrfs, 8 bytes @372
ub4 kscnbas @372 0x00000000
ub2 kscnwrp @376 0x0000
ub4 kcvfhrft @380 0x00000000
struct kcvfhafs, 8 bytes @384
ub4 kscnbas @384 0x00000000
ub2 kscnwrp @388 0x0000
ub4 kcvfhbbc @392 0x00000000
ub4 kcvfhncb @396 0x00000000
ub4 kcvfhmcb @400 0x00000000
ub4 kcvfhlcb @404 0x00000000
ub4 kcvfhbcs @408 0x00000000
ub2 kcvfhofb @412 0x0000
ub2 kcvfhnfb @414 0x0000
ub4 kcvfhprc @416 0x00000000
struct kcvfhprs, 8 bytes @420
ub4 kscnbas @420 0x00000000
ub2 kscnwrp @424 0x0000
struct kcvfhprfs, 8 bytes @428
ub4 kscnbas @428 0x00000000
ub2 kscnwrp @432 0x0000
ub4 kcvfhtrt @444 0x00000000
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