LINUX AS 4 2.6.9
ORACLE 9.2.0.4
SQL> select file_id,block_id,blocks from dba_extents where segment_name='I_TEST' and owner='DBLU';
FILE_ID BLOCK_ID BLOCKS
---------- ---------- ----------
16 2609769 8
问个BMB结构问题,为什么是这样的顺序:FIRST LEVEL BITMAP BLOCK->SECOND LEVEL BITMAP BLOCK->PAGETABLE SEGMENT HEADER,
而不是PAGETABLE SEGMENT HEADER->SECOND LEVEL BITMAP BLOCK->FIRST LEVEL BITMAP以下是跟踪文件:
*** SESSION ID
55.24913) 2010-08-24 17:06:46.714
Start dump data blocks tsn: 15 file#: 16 minblk 2609769 maxblk 2609769buffer tsn: 15 rdba: 0x0427d269 (16/2609769)
scn: 0x0023.593588a2 seq: 0x02 flg: 0x00 tail: 0x88a22002
frmt: 0x02 chkval: 0x0000 type: 0x20=FIRST LEVEL BITMAP BLOCK
Dump of First Level Bitmap Block
--------------------------------
nbits : 2 nranges: 1 parent dba: 0x0427d26a poffset: 0
unformatted: 0 total: 8 first useful block: 3
owning instance : 1
instance ownership changed at 08/24/2010 17:00:28
Last successful Search 08/24/2010 17:00:28
Freeness Status: nf1 0 nf2 2 nf3 0 nf4 0
Extent Map Block Offset: 4294967295
First free datablock : 4
Bitmap block lock opcode 0
Locker xid: : 0x0000.000.00000000
Highwater:: 0x0427d271 ext#: 0 blk#: 8 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 5
mapblk 0x00000000 offset: 0
HWM Flag: HWM Set
--------------------------------------------------------
DBA Ranges :
--------------------------------------------------------
0x0427d269 Length: 8 Offset: 0
0:Metadata 1:Metadata 2:Metadata 3:FULL
4:25-50% free 5:FULL 6:FULL 7:25-50% free
--------------------------------------------------------
End dump data blocks tsn: 15 file#: 16 minblk 2609769 maxblk 2609769
Start dump data blocks tsn: 15 file#: 16 minblk 2609770 maxblk 2609770
buffer tsn: 15 rdba: 0x0427d26a (16/2609770)
scn: 0x0023.593588a0 seq: 0x01 flg: 0x00 tail: 0x88a02101
frmt: 0x02 chkval: 0x0000 type: 0x21=SECOND LEVEL BITMAP BLOCK
Dump of Second Level Bitmap Block
number: 1 nfree: 1 ffree: 0 pdba: 0x0427d26b
opcode:0
xid:
L1 Ranges :
--------------------------------------------------------
0x0427d269 Free: 3 Inst: 1
--------------------------------------------------------
End dump data blocks tsn: 15 file#: 16 minblk 2609770 maxblk 2609770
Start dump data blocks tsn: 15 file#: 16 minblk 2609771 maxblk 2609771
buffer tsn: 15 rdba: 0x0427d26b (16/2609771)
scn: 0x0023.593588a0 seq: 0x02 flg: 0x00 tail: 0x88a02302
frmt: 0x02 chkval: 0x0000 type: 0x23=PAGETABLE SEGMENT HEADER
Extent Control Header
-----------------------------------------------------------------
Extent Header:: spare1: 0 spare2: 0 #extents: 1 #blocks: 8
last map 0x00000000 #maps: 0 offset: 2716
Highwater:: 0x0427d271 ext#: 0 blk#: 8 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 5
mapblk 0x00000000 offset: 0
Unlocked
--------------------------------------------------------
Low HighWater Mark :
Highwater:: 0x0427d271 ext#: 0 blk#: 8 ext size: 8
[ 本帖最后由 microsoft_fly 于 2010-8-24 17:28 编辑 ]
ORACLE 9.2.0.4
SQL> select file_id,block_id,blocks from dba_extents where segment_name='I_TEST' and owner='DBLU';
FILE_ID BLOCK_ID BLOCKS
---------- ---------- ----------
16 2609769 8
问个BMB结构问题,为什么是这样的顺序:FIRST LEVEL BITMAP BLOCK->SECOND LEVEL BITMAP BLOCK->PAGETABLE SEGMENT HEADER,
而不是PAGETABLE SEGMENT HEADER->SECOND LEVEL BITMAP BLOCK->FIRST LEVEL BITMAP以下是跟踪文件:
*** SESSION ID

Start dump data blocks tsn: 15 file#: 16 minblk 2609769 maxblk 2609769buffer tsn: 15 rdba: 0x0427d269 (16/2609769)
scn: 0x0023.593588a2 seq: 0x02 flg: 0x00 tail: 0x88a22002
frmt: 0x02 chkval: 0x0000 type: 0x20=FIRST LEVEL BITMAP BLOCK
Dump of First Level Bitmap Block
--------------------------------
nbits : 2 nranges: 1 parent dba: 0x0427d26a poffset: 0
unformatted: 0 total: 8 first useful block: 3
owning instance : 1
instance ownership changed at 08/24/2010 17:00:28
Last successful Search 08/24/2010 17:00:28
Freeness Status: nf1 0 nf2 2 nf3 0 nf4 0
Extent Map Block Offset: 4294967295
First free datablock : 4
Bitmap block lock opcode 0
Locker xid: : 0x0000.000.00000000
Highwater:: 0x0427d271 ext#: 0 blk#: 8 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 5
mapblk 0x00000000 offset: 0
HWM Flag: HWM Set
--------------------------------------------------------
DBA Ranges :
--------------------------------------------------------
0x0427d269 Length: 8 Offset: 0
0:Metadata 1:Metadata 2:Metadata 3:FULL
4:25-50% free 5:FULL 6:FULL 7:25-50% free
--------------------------------------------------------
End dump data blocks tsn: 15 file#: 16 minblk 2609769 maxblk 2609769
Start dump data blocks tsn: 15 file#: 16 minblk 2609770 maxblk 2609770
buffer tsn: 15 rdba: 0x0427d26a (16/2609770)
scn: 0x0023.593588a0 seq: 0x01 flg: 0x00 tail: 0x88a02101
frmt: 0x02 chkval: 0x0000 type: 0x21=SECOND LEVEL BITMAP BLOCK
Dump of Second Level Bitmap Block
number: 1 nfree: 1 ffree: 0 pdba: 0x0427d26b
opcode:0
xid:
L1 Ranges :
--------------------------------------------------------
0x0427d269 Free: 3 Inst: 1
--------------------------------------------------------
End dump data blocks tsn: 15 file#: 16 minblk 2609770 maxblk 2609770
Start dump data blocks tsn: 15 file#: 16 minblk 2609771 maxblk 2609771
buffer tsn: 15 rdba: 0x0427d26b (16/2609771)
scn: 0x0023.593588a0 seq: 0x02 flg: 0x00 tail: 0x88a02302
frmt: 0x02 chkval: 0x0000 type: 0x23=PAGETABLE SEGMENT HEADER
Extent Control Header
-----------------------------------------------------------------
Extent Header:: spare1: 0 spare2: 0 #extents: 1 #blocks: 8
last map 0x00000000 #maps: 0 offset: 2716
Highwater:: 0x0427d271 ext#: 0 blk#: 8 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 5
mapblk 0x00000000 offset: 0
Unlocked
--------------------------------------------------------
Low HighWater Mark :
Highwater:: 0x0427d271 ext#: 0 blk#: 8 ext size: 8
[ 本帖最后由 microsoft_fly 于 2010-8-24 17:28 编辑 ]
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