SQL Server進行Crash Recovery

我們看一下SQL Server的情況，使用DBCC fileheader命令來讀取file header page，編號為10是我的一個使用者庫SSS的資料庫ID

環境：SQL Server2012 64位

SELECT DB_ID('sss')DBCC fileheader(10)

（圖一）

（圖二）

（圖三）

（圖四）

從上面的圖大家應該發現一些規律

RecoveryForkLSN：Cash Recovery的時候需要呼叫的lsn，也是RedoStartLSN：27000000027100001
ReadOnlyLsn：只讀模式資料庫
ReadWriteLsn：讀寫模式資料庫

因為file header page是每個資料庫的mdf檔案的第一個頁面，啟動的過程裡面其實最重要也是最耗時就是資料庫redo和undo過程

所以把Redo Start LSN放在file header page也就不無道理了，資料庫一啟動馬上就讀取LSN資訊，然後到LDF檔案裡讀取日誌

資料庫第0頁:file header page

資料庫第1頁：PFS  (Page Free Space) ,也叫頁面自由空間

資料庫第2頁：GAM 全域性分配對映(Global Allocation Map，GAM)頁面 

資料庫第3頁：SGAM 共享全域性分配對映(Shared Global Allocation Map，SGAM)頁面 

第4頁沒有資料

第5頁沒有資料

資料庫第6頁：DCM 差異變更(Differential Changed Map，DCM)頁面

資料庫第7頁：BCM 批次更改對映（Bulk Changed Map）頁面

資料庫第8頁：sys.sysqnames 存在於每個資料庫中。

資料庫第9頁：boot page 資料庫根據這個頁面的資訊來啟動的

boot page是放在第9頁不是放在第0頁，為什麼呢？因為資料庫先要進行Cash Recovery才能啟動啊

--看一下file header pageDBCC TRACEON(3604,-1)GODBCC PAGE([sss],1,0,3)GO

DBCC 執行完畢。如果 DBCC 輸出了錯誤資訊，請與系統管理員聯絡。PAGE: (1:0)BUFFER:BUF @0x00000002FDABA800bpage = 0x00000002EFF88000          bhash = 0x0000000000000000          bpageno = (1:0)bdbid = 10                          breferences = 0                     bcputicks = 88bsampleCount = 1                    bUse1 = 36811                       bstat = 0x9blog = 0x15ab215a                   bnext = 0x0000000000000000          PAGE HEADER:Page @0x00000002EFF88000m_pageId = (1:0)                    m_headerVersion = 1                 m_type = 15m_typeFlagBits = 0x0                m_level = 0                         m_flagBits = 0x208m_objId (AllocUnitId.idObj) = 99    m_indexId (AllocUnitId.idInd) = 0   Metadata: AllocUnitId = 6488064Metadata: PartitionId = 0           Metadata: IndexId = 0               Metadata: ObjectId = 99m_prevPage = (0:0)                  m_nextPage = (0:0)                  pminlen = 0m_slotCnt = 1                       m_freeCnt = 7029                    m_freeData = 7551m_reservedCnt = 0                   m_lsn = (878:901:1)                 m_xactReserved = 0m_xdesId = (0:0)                    m_ghostRecCnt = 0                   m_tornBits = -582568961DB Frag ID = 1                      Allocation StatusGAM (1:2) = ALLOCATED               SGAM (1:3) = NOT ALLOCATED          PFS (1:1) = 0x44 ALLOCATED 100_PCT_FULLDIFF (1:6) = CHANGED                ML (1:7) = NOT MIN_LOGGED           File Header Data:Record Type = PRIMARY_RECORD        Record Attributes =  NULL_BITMAP VARIABLE_COLUMNSRecord Size = 1065                  Memory Dump @0x000000000D1BB9560000000000000000:   30000800 00000000 31000000 00000000 002e007f  0.......1...........0000000000000014:   007f0081 00830087 008b008f 0093009d 00a700b1  ....................0000000000000028:   00b100b5 00b900bd 00c100cb 00e700f1 00fb0005  ....................000000000000003C:   0115011f 012f0133 013d013d 01430153 01530153  ...../.3.=.=.C.S.S.S0000000000000050:   01530153 01530153 01630163 0163016d 01770193  .S.S.S.S.c.c.c.m.w..0000000000000064:   019d01ad 01c901d1 012904c5 cbddcf11 44c34889  .........)......D.H.0000000000000078:   52cc552b 3eba7601 00010080 c00500ff ffffff80  R.U+>.v.............000000000000008C:   00000000 00000000 00000000 00000000 00000000  ....................00000000000000A0:   00000000 00000000 00000000 00000000 00800100  ....................00000000000000B4:   00000000 00ffffff ff000200 001b0000 000f0100  ....................00000000000000C8:   0001001b 0000000f 01000001 00000053 d02a7787  ...............S.*w.00000000000000DC:   3ec94e97 926f64fe 3febf81b 000000c3 000000b2  >.N..od.?...........00000000000000F0:   00000000 00000000 0000006e 0300006d 0300002e  ...........n...m....0000000000000104:   00284a9c 892994c1 4692f4f1 e3c51d34 90000000  .(J..)..F......4....0000000000000118:   00000000 00000014 51b676d9 b1a34abc c0185ae9  ........Q.v...J...Z.000000000000012C:   6fccb108 0000001b 0000000f 01000001 00730073  o................s.s0000000000000140:   0073006a 49d8681b 194f469a 40c068d8 57651953  .s.jI.h..OF.@.h.We.S0000000000000154:   d02a7787 3ec94e97 926f64fe 3febf800 00000000  .*w.>.N..od.?.......0000000000000168:   00000000 00000000 00000000 00000000 00000000  ....................000000000000017C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000190:   0000001b 000000c3 000000b2 006a49d8 681b194f  .............jI.h..O00000000000001A4:   469a40c0 68d85765 19000000 00000000 00000000  F.@.h.We............00000000000001B8:   00000000 00000000 00000000 00000000 00000000  ....................00000000000001CC:   00000000 00000000 00000000 00000000 00000000  ....................00000000000001E0:   00000000 00000000 00000000 00000000 00000000  ....................00000000000001F4:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000208:   00000000 00000000 00000000 00000000 00000000  ....................000000000000021C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000230:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000244:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000258:   00000000 00000000 00000000 00000000 00000000  ....................000000000000026C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000280:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000294:   00000000 00000000 00000000 00000000 00000000  ....................00000000000002A8:   00000000 00000000 00000000 00000000 00000000  ....................00000000000002BC:   00000000 00000000 00000000 00000000 00000000  ....................00000000000002D0:   00000000 00000000 00000000 00000000 00000000  ....................00000000000002E4:   00000000 00000000 00000000 00000000 00000000  ....................00000000000002F8:   00000000 00000000 00000000 00000000 00000000  ....................000000000000030C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000320:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000334:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000348:   00000000 00000000 00000000 00000000 00000000  ....................000000000000035C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000370:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000384:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000398:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003AC:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003C0:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003D4:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003E8:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003FC:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000410:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000424:   00000000 00                                   .....  BindingID = cfddcbc5-4411-48c3-8952-cc552b3eba76                         FileIdProp = 1FileGroupId = 1                     Size = 49280                        MaxSize = 65535Growth = 128                        Perf = 0                            BackupLsn = (0:0:0)FirstUpdateLsn = (0:0:0)            OldestRestoredLsn = (0:0:0)         FirstNonloggedUpdateLsn = [NULL]MinSize = 384                       Status = 0                          UserShrinkSize = 65535SectorSize = 512                    MaxLsn = (27:271:1)                 FirstLsn = (27:195:178)CreateLsn = (0:0:0)                 DifferentialBaseLsn = (878:877:46)  DifferentialBaseGuid = 899c4a28-9429-46c1-92f4-f1e3c51d3490              FileOfflineLsn = (0:0:0)FileIdGuid = 76b65114-b1d9-4aa3-bcc0-185ae96fccb1                        RestoreStatus = 8RestoreRedoStartLsn = (27:271:1)    RestoreSourceGuid = 68d8496a-191b-464f-9a40-c068d8576519HardenedSkipLsn = [NULL]            ReplTxfTruncationLsn = [NULL]       TxfBackupLsn = [NULL]FstrContainerSize = [NULL]          MaxLsnBranchId = 772ad053-3e87-4ec9-9792-6f64fe3febf8SecondaryRedoStartLsn = [NULL]      SecondaryDifferentialBaseLsn = [NULL]ReadOnlyLsn = (0:0:0)               ReadWriteLsn = (0:0:0)              RestoreDifferentialBaseLsn = (27:195:178)                                RestoreDifferentialBaseGuid = 68d8496a-191b-464f-9a40-c068d8576519       RestorePathOriginhex (dec) = 0x00000000:00000000:0000 (0:0:0)                             m_guid = 00000000-0000-0000-0000-000000000000                            DatabaseEncryptionFileState.m_maxScannedPage = 0                         DatabaseEncryptionFileState.m_keyId = 0FCBFileDEKm_dbeStatusBits = 0                 m_dtCreated = 1900-01-01 00:00:00.000m_dtLastRegenerated = 1900-01-01 00:00:00.000                            m_dtLastModified = 1900-01-01 00:00:00.000                               m_dtLastSet = 1900-01-01 00:00:00.000m_dtOpened = 1900-01-01 00:00:00.000m_algId = 0                         m_algId = 0m_dwBitLen = 0                      m_cbThumbprint = 0                  m_rgbThumbprint = 0xDBCC 執行完畢。如果 DBCC 輸出了錯誤資訊，請與系統管理員聯絡。

--看一下boot page的內容DBCC TRACEON(3604,-1)GODBCC PAGE([sss],1,9,3)GO

Page @0x00000002EA7DE000m_pageId = (1:9)                    m_headerVersion = 1                 m_type = 13m_typeFlagBits = 0x0                m_level = 0                         m_flagBits = 0x200m_objId (AllocUnitId.idObj) = 99    m_indexId (AllocUnitId.idInd) = 0   Metadata: AllocUnitId = 6488064Metadata: PartitionId = 0           Metadata: IndexId = 0               Metadata: ObjectId = 99m_prevPage = (0:0)                  m_nextPage = (0:0)                  pminlen = 0m_slotCnt = 1                       m_freeCnt = 6590                    m_freeData = 1600m_reservedCnt = 0                   m_lsn = (878:1345:2)                m_xactReserved = 0m_xdesId = (0:0)                    m_ghostRecCnt = 0                   m_tornBits = 2000067799DB Frag ID = 1                      Allocation StatusGAM (1:2) = ALLOCATED               SGAM (1:3) = NOT ALLOCATED          PFS (1:1) = 0x64 MIXED_EXT ALLOCATED 100_PCT_FULL                        DIFF (1:6) = CHANGEDML (1:7) = NOT MIN_LOGGED           Slot 0, Offset 0x60, Length 1504, DumpStyle BYTERecord Type = PRIMARY_RECORD        Record Attributes =                 Record Size = 1504Memory Dump @0x000000000D1BA0600000000000000000:   0000e005 c2026302 00000000 00000000 00000000  ......c.............0000000000000014:   00000000 00000000 00000000 00000000 08008100  ....................0000000000000028:   ae80847c bba19900 0ca30000 73007300 73002020  ...|........s.s.s.  000000000000003C:   20202020 20202020 20202020 20202020 20202020                      0000000000000050:   20202020 20202020 20202020 20202020 20202020                      0000000000000064:   20202020 20202020 20202020 20202020 20202020                      0000000000000078:   20202020 20202020 20202020 20202020 20202020                      000000000000008C:   20202020 20202020 20202020 20202020 20202020                      00000000000000A0:   20202020 20202020 20202020 20202020 20202020                      00000000000000B4:   20202020 20202020 20202020 20202020 20202020                      00000000000000C8:   20202020 20202020 20202020 20202020 20202020                      00000000000000DC:   20202020 20202020 20202020 20202020 20202020                      00000000000000F0:   20202020 20202020 20202020 20202020 20202020                      0000000000000104:   20202020 20202020 20202020 20202020 20202020                      0000000000000118:   20202020 20202020 20202020 20202020 20202020                      000000000000012C:   20202020 20202020 06000000 0a006e00 70170000          ......n.p...0000000000000140:   00000000 00000000 00000000 00000000 6e030000  ................n...0000000000000154:   6d030000 2e004000 6e030000 3a050000 0c000200  m.....@.n...:.......0000000000000168:   00000000 00000000 00000000 6e030000 3a050000  ............n...:...000000000000017C:   0c000000 c2271400 00000000 24d00000 00000000  .....'......$.......0000000000000190:   00000041 00000000 53d02a77 873ec94e 97926f64  ...A....S.*w.>.N..od00000000000001A4:   fe3febf8 00e67dbf 00000000 00000000 00000000  .?....}.............00000000000001B8:   00000000 1b000000 0f010000 01000000 d305e86e  ...................n00000000000001CC:   6e28d54a 892e8070 c5aec1fa 1b000000 0f010000  n(.J...p............00000000000001E0:   01000000 53d02a77 873ec94e 97926f64 fe3febf8  ....S.*w.>.N..od.?..00000000000001F4:   284a9c89 2994c146 92f4f1e3 c51d3490 14000000  (J..)..F......4.....0000000000000208:   01006302 00000000 00000000 00000000 22000000  ..c............."...000000000000021C:   d0000000 03000400 80000000 00000000 00000000  ....................0000000000000230:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000244:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000258:   00000000 00000000 00000000 00000000 00000000  ....................000000000000026C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000280:   c9020000 1e000000 e3000000 c3f9a100 bda30000  ....................0000000000000294:   00000000 00000000 00000000 00000000 553cda00  ................U<..00000000000002a8:>.]J.K00000000000002BC:   b9a2abb7 5245120c 00000000 00000000 00000000  ....RE..............00000000000002D0:   00000000 00000000 00000000 00000000 96010000  ....................00000000000002E4:   00010000 00000000 00000000 00000000 02000000  ....................00000000000002F8:   00000000 00000000 00000000 00000000 00000000  ....................000000000000030C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000320:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000334:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000348:   00000000 00000000 00000000 00000000 00000000  ....................000000000000035C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000370:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000384:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000398:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003AC:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003C0:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003D4:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003E8:   00000000 00000000 00000000 00000000 00000000  ....................00000000000003FC:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000410:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000424:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000438:   00000000 00000000 00000000 00000000 00000000  ....................000000000000044C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000460:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000474:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000488:   00000000 00000000 00000000 00000000 00000000  ....................000000000000049C:   00000000 00000000 00000000 00000000 00000000  ....................00000000000004B0:   00000000 00000000 00000000 00000000 00000000  ....................00000000000004C4:   00000000 00000000 00000000 00000000 00000000  ....................00000000000004D8:   00000000 00000000 00000000 00000000 00000000  ....................00000000000004EC:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000500:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000514:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000528:   00000000 00000000 00000000 00000000 00000000  ....................000000000000053C:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000550:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000564:   00000000 00000000 00000000 00000000 00000000  ....................0000000000000578:   00000000 00000000 00000000 00000000 00000000  ....................000000000000058C:   00000000 00000000 00000000 00000000 00000000  ....................00000000000005A0:   00000000 00000000 00000000 20000000 78000000  ............ ...x...00000000000005B4:   43000000 00000000 00000000 00000000 00000000  C...................00000000000005C8:   00000000 00000000 00000000 00000000 00000000  ....................00000000000005DC:   00000000                                      ....   DBINFO @0x000000000D1BA060dbi_version = 706                   dbi_createVersion = 611             dbi_SEVersion = 0dbi_dvSplitPoint = 0:0:0 (0x00000000:00000000:0000)                      dbi_dbbackupLSN = 0:0:0 (0x00000000:00000000:0000)                       dbi_LastLogBackupTime = 1900-01-01 00:00:00.000                          dbi_nextseqnum = 1900-01-01 00:00:00.000                                 dbi_status = 0x00810008dbi_crdate = 2014-04-13 09:19:21.370dbi_dbname = sss                    dbi_dbid = 10dbi_cmptlevel = 110                 dbi_masterfixups = 0                dbi_maxDbTimestamp = 6000dbi_dbbackupLSN = 0:0:0 (0x00000000:00000000:0000)                       dbi_RebuildLogs = 0dbi_differentialBaseLSN = 878:877:46 (0x0000036e:0000036d:002e)          dbi_RestoreFlags = 0x0040dbi_checkptLSN = 878:1338:12 (0x0000036e:0000053a:000c)                  dbi_dbccFlags = 2dbi_COWLastLSN = 0:0:0 (0x00000000:00000000:0000)                        dbi_DirtyPageLSN = 878:1338:12 (0x0000036e:0000053a:000c)                dbi_RecoveryFlags = 0x00000000dbi_lastxact = 0x1427c2             dbi_collation = 53284               dbi_relstat = 0x41000000dbi_familyGUID = 772ad053-3e87-4ec9-9792-6f64fe3febf8                    dbi_maxLogSpaceUsed = 3212699136dbi_recoveryForkNameStackentry 0hex (dec) = 0x0000001b:0000010f:0001 (27:271:1)                          m_guid = 6ee805d3-286e-4ad5-892e-8070c5aec1fa                            entry 1hex (dec) = 0x0000001b:0000010f:0001 (27:271:1)                          m_guid = 772ad053-3e87-4ec9-9792-6f64fe3febf8                            dbi_differentialBaseGuid = 899c4a28-9429-46c1-92f4-f1e3c51d3490          dbi_firstSysIndexes = 0001:00000014dbi_oldestBackupXactLSN = 0:0:0 (0x00000000:00000000:0000)               dbi_versionChangeLSN = 34:208:3 (0x00000022:000000d0:0003)               dbi_mdUpgStat = 0x0004dbi_category = 0x0000000000000080   dbi_safetySequence = 0              dbi_dbMirrorId = 00000000-0000-0000-0000-000000000000                    dbi_pageUndoLsn = 0:0:0 (0x00000000:00000000:0000)                       dbi_pageUndoState = 0dbi_disabledSequence = 0            dbi_dbmRedoLsn = 0:0:0 (0x00000000:00000000:0000)dbi_dbmOldestXactLsn = 0:0:0 (0x00000000:00000000:0000)                  dbi_CloneCpuCount = 0dbi_CloneMemorySize = 0             dbi_updSysCatalog = 1900-01-01 00:00:00.000dbi_LogBackupChainOrigin = 713:30:227 (0x000002c9:0000001e:00e3)         dbi_dbccLastKnownGood = 2014-10-07 09:49:44.117                          dbi_roleSequence = 0dbi_dbmHardenedLsn = 0:0:0 (0x00000000:00000000:0000)                    dbi_localState = 0dbi_safety = 0                      dbi_modDate = 2014-04-06 13:14:34.310dbi_verRDB = 184552376              dbi_lazyCommitOption = 0            dbi_svcBrokerGUID = 953e1259-4a5d-4b11-b9a2-abb75245120c                 dbi_svcBrokerOptions = 0x00000000dbi_dbmLogZeroOutstanding = 0       dbi_dbmLastGoodRoleSequence = 0     dbi_dbmRedoQueue = 0dbi_dbmRedoQueueType = 0            dbi_rmidRegistryValueDeleted = 0    dbi_dbmConnectionTimeout = 0dbi_fragmentId = 0                  dbi_AuIdNext = 1099511628182        dbi_MinSkipLsn = 0:0:0 (0x00000000:00000000:0000)                        dbi_commitTsOfcheckptLSN = 2dbi_dbEmptyVersionState = 0         dbi_CurrentGeneration = 0           dbi_EncryptionHistoryScan 0hex (dec) = 0x00000000:00000000:0000 (0:0:0)                             EncryptionScanInfo:ScanId = 0       Scan 1hex (dec) = 0x00000000:00000000:0000 (0:0:0)                             EncryptionScanInfo:ScanId = 0       Scan 2hex (dec) = 0x00000000:00000000:0000 (0:0:0)                             EncryptionScanInfo:ScanId = 0       dbi_latestVersioningUpgradeLSN = 32:120:67 (0x00000020:00000078:0043)    dbi_splitAGE = 0dbi_PendingRestoreOutcomesId = 00000000-0000-0000-0000-000000000000      dbi_ContianmentState = 0