5.2.4 数据文件头部信息的奥秘

DBCC TRACEON(3604)
GO
DBCC PAGE(master,1,0,3)
GO

/*页面ID，为第1个文件的ID为0的页面*/
PAGE: (1:0)
/*内存缓冲区中的头部信息*/
BUFFER:
BUF @0x02D06620
bpage = 0x03490000
bhash = 0x00000000
bpageno = (1:0)
bdbid = 1
breferences = 0
bUse1 = 31003
bstat = 0x1c00109
blog = 0x32159
bnext = 0x00000000
/*页面头部信息*/
PAGE HEADER:
Page @0x03490000
m_pageId = (1:0)
m_headerVersion = 1 
m_type = 15
m_typeFlagBits = 0x0    
m_level = 0
m_flagBits = 0x8
m_objId (AllocUnitId.idObj) = 99
m_indexId (AllocUnitId.idInd) = 0
Metadata: AllocUnitId = 6488064
Metadata: PartitionId = 0
Metadata: IndexId = 0
Metadata: ObjectId = 99
m_prevPage = (0:0)
m_nextPage = (0:0) 
pminlen = 0
m_slotCnt = 1
m_freeCnt = 7937
m_freeData = 3059
m_reservedCnt = 0
m_lsn = (149:448:1)
m_xactReserved = 0
m_xdesId = (0:0) 
m_ghostRecCnt = 0 
m_tornBits = -1073741694
/*数据文件主要管理页面分配信息*/
Allocation Status
GAM (1:2) = ALLOCATED
SGAM (1:3) = NOT ALLOCATED
PFS (1:1) = 0x44 ALLOCATED 100_PCT_FULL
DIFF (1:6) = CHANGED
ML (1:7) = NOT MIN_LOGGED            
/*数据文件头部信息*/
File Header Data:
Record Type = PRIMARY_RECORD
Record Attributes =  NULL_BITMAP VARIABLE_COLUMNS
Memory Dump @0x24BCCB56
00000000:   30000800 00000000 17000000 0016004b †..............K         
00000010:   004b004d 004f0053 0057005b 005f005f †K.M.O.S.W.[._._         
00000020:   00690069 0069006d 00710075 00790079 †i.i.i.m.q.u.y.y         
00000030:   00790079 0083008d 009d004c 3f4c23ac †y.y.......L?L#.         
00000040:   53f24583 29615c2f 5ddaba01 00010000 †.E.)a\/].......         
00000050:   020000ff ffffff0a 00000000 0000007b †..............{         
00000060:   000000d8 0000000a 00000200 00000010 †...............         
00000070:   00ffffff ff001000 00000000 00000000 †...............         
00000080:   00000000 00000000 00000000 00000000 †...............         
00000090:   00000000 00000000 00000000 00† ?† ?† ?† ?.............            
/*数据文件头部存储的数据转换后的值*/
BindingID = 234c3f4c-53ac-45f2-8329-615c2f5ddaba 
FileGroupId = 1
FileIdProp = 1
Size = 512
MaxSize = 65535
Growth = 10
Perf = 0 
BackupLsn = [NULL]
MaxLsn = [NULL]
FirstLsn = [NULL]
OldestRestoredLsn = [NULL]
FirstUpdateLsn = (123:216:10)
FirstNonloggedUpdateLsn = [NULL]
CreateLsn = (0:0:0)
DifferentialBaseLsn = (0:0:0)
DifferentialBaseGuid = 00000000-0000-0000-0000-000000000000
MinSize = 512
Status = 0
UserShrinkSize = 65535