【YashanDB知识库】如何dump数据文件，转换rowid，查询对应内容

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问题现象

客户环境有时候会遇到文件损坏的情况，需要dump文件，根据rowid查询数据情况。

问题的风险及影响

熟练掌握崖山数据文件dump操作，并识别rowid，在故障的情况下可以快速确认相应的数据情况，查找需要的数据。

问题影响的版本

YashanDB版本所有版本

问题分析和处理过程

1、在故障情况下，直接查询表数据，会遇到YAS-02147的错误。

2、崖山提供dump命令，可以dump出db数据文件，但不包含数据内容。

详细说明见dump | YashanDB Doc (yasdb.com)

3、确认文件id和blockid

在上述命令中，dump的时候需要文件id和blockid。

文件id对应V$datafile表空间所在的文件id，如下面users表空间文件id是4。

表block对应dba_segments中block起始位置及数量，如下面CUSTOMER从block 131开始，有8个block。

根据上面分析，执行dump命令ALTER SYSTEM DUMP DATAFILE 4 MINBLOCK 131 MAXBLOCK 140，结果如下：

点击查看代码

SQL> ALTER SYSTEM DUMP DATAFILE 4 MINBLOCK 131 MAXBLOCK 140;

Succeed.

SQL> exit

[cod@6c5c2b1ac6f0 trace]$ ls -l

total 8

-rw-rw-r-- 1 cod cod 5541 Jul 30 10:18 yashan_yas_21.trc

[cod@6c5c2b1ac6f0 trace]$ cat yashan_yas_21.trc

*** 2024-07-30 10:17:52.212

Start dump data blocks TS#: 4 FILE#: 4 minblk 132 maxblk 132

Block dump from disk:

warning: disk dump block information is incompleted, file#: 4 blk#: 132 ts#: 4

*** 2024-07-30 10:18:53.922

Start dump data blocks TS#: 4 FILE#: 4 minblk 131 maxblk 140

Block dump from cache:

BUFFER CTRL DUMP

  FILE#: 4 BLK#: 131 TS#: 4

  bucketId: 29579 crNext: 4294967295 hashNext:4294967295

  lruListId: 2 lru: [7546, 7537]

  resStatus: 0 refCount: 1 pcFlag: 0

  scn: 0 ext: 0 node: 0 xsn: 0 ssn: 0

  lastLfn: 0 dtyList: [NULL, NULL]

  truncPoint: [0, 0, 0, 0]

BUFFER CTRL DUMP END

DISK BLOCK DUMP

segment

head: id 0-131, type 33, instance id 0 lsn 5031, checksum: 0, change num 4, isEncrypted 0, isCompressed 0

segType: heap

dataOid: 2486

ssm tree: search entry: 0-129, level: 1

level[0]: ssm block count: 1, current block: 0-128

level[1]: ssm block count: 1, current block: 0-129

level[2]: ssm block count: 1, current block: 0-130

hwm L1: 0-128

hwm L1 node: 7

extents lhwm: block id: 0-136, extent idx: 0, map block: 0-131, offset: 0, blkIdx: 8, used block count: 8. lhwmL1: 0-128

extent ctrl: extent count: 1, block count: 8, map count: 0 , extent map offset: 380

last map block: 63-67108863, offset: 0, extents change number: 0

extents hwm: block id: 0-136, extent idx: 0, offset: 0, unformatted block count: 0, used block count: 8, map block: 63-67108863

extents map: extent count: 1, capacity: 487, next map: 63-67108863, map nodes:

id: 0-128 size: 8

0. L1 block id: 0-128 data block id: 0-132

tail: change num: 4

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from disk:

warning: disk dump block information is incompleted, file#: 4 blk#: 132 ts#: 4

*** 2024-07-30 10:18:53.922

Block dump from cache:

BUFFER CTRL DUMP

  FILE#: 4 BLK#: 133 TS#: 4

  bucketId: 29581 crNext: 4294967295 hashNext:4294967295

  lruListId: 2 lru: [7548, 7546]

  resStatus: 0 refCount: 1 pcFlag: 0

  scn: 0 ext: 0 node: 0 xsn: 0 ssn: 0

  lastLfn: 0 dtyList: [NULL, NULL]

  truncPoint: [0, 0, 0, 0]

BUFFER CTRL DUMP END

DISK BLOCK DUMP

heap data

head: id 0-133, type 4, instance id 0 lsn 5029, checksum: 0, change num 1, isEncrypted 0, isCompressed 0

dataOid: 2486, extent change number: 0

block scn: 0, map block: 0-128, slot: 5, freeness: 5

rows: 0, dirs: 0, xslots: 0, si xslots: 0, free size: 8108, free begin: 80, free end: 8188 free dir: 4095

tail: change num: 1

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from cache:

BUFFER CTRL DUMP

  FILE#: 4 BLK#: 134 TS#: 4

  bucketId: 29582 crNext: 4294967295 hashNext:4294967295

  lruListId: 2 lru: [4294967295, 7547]

  resStatus: 0 refCount: 1 pcFlag: 0

  scn: 0 ext: 0 node: 0 xsn: 0 ssn: 0

  lastLfn: 0 dtyList: [NULL, NULL]

  truncPoint: [0, 0, 0, 0]

BUFFER CTRL DUMP END

DISK BLOCK DUMP

heap data

head: id 0-134, type 4, instance id 0 lsn 5029, checksum: 0, change num 1, isEncrypted 0, isCompressed 0

dataOid: 2486, extent change number: 0

block scn: 0, map block: 0-128, slot: 6, freeness: 5

rows: 0, dirs: 0, xslots: 0, si xslots: 0, free size: 8108, free begin: 80, free end: 8188 free dir: 4095

tail: change num: 1

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from cache:

BUFFER CTRL DUMP

  FILE#: 4 BLK#: 135 TS#: 4

  bucketId: 29583 crNext: 4294967295 hashNext:4294967295

  lruListId: 1 lru: [4294967295, 7543]

  resStatus: 0 refCount: 1 pcFlag: 0

  scn: 0 ext: 0 node: 0 xsn: 0 ssn: 0

  lastLfn: 0 dtyList: [NULL, NULL]

  truncPoint: [0, 0, 0, 0]

BUFFER CTRL DUMP END

DISK BLOCK DUMP

heap data

head: id 0-135, type 4, instance id 0 lsn 5030, checksum: 0, change num 4, isEncrypted 0, isCompressed 0

dataOid: 2486, extent change number: 0

block scn: 581620909456666624, map block: 0-128, slot: 7, freeness: 1

rows: 1, dirs: 1, xslots: 2, si xslots: 0, free size: 2022, free begin: 6116, free end: 8138 free dir: 4095

row[0]: size: 6036 xslot id: 0 columns: 3 format/link/migr/deleted/compact:1/0/0/0/0

xslot[0]: xid: 25-11349-1 active: 0 owscn: 0 fastcommit: 1 ura: block: 0-15758, ver: 0, dir: 1 ssn: 3055202304 fsc: 21794 mfb: 2066 scn: 581620909456666624

xslot[1]: xid: 0-0-0 active: 0 owscn: 0 fastcommit: 0 ura: block: 0-0, ver: 0, dir: 0 ssn: 0 fsc: 0 mfb: 0 scn: 0

tail: change num: 4

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from disk:

DISK BLOCK DUMP

unknown

head: id 0-136, type 0, instance id 0 lsn 9, checksum: 999298229, change num 0, isEncrypted 0, isCompressed 0

unknown type 0

tail: change num: 0

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from disk:

DISK BLOCK DUMP

unknown

head: id 0-137, type 0, instance id 0 lsn 9, checksum: 3105528825, change num 0, isEncrypted 0, isCompressed 0

unknown type 0

tail: change num: 0

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from disk:

DISK BLOCK DUMP

unknown

head: id 0-138, type 0, instance id 0 lsn 9, checksum: 996768988, change num 0, isEncrypted 0, isCompressed 0

unknown type 0

tail: change num: 0

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from disk:

DISK BLOCK DUMP

unknown

head: id 0-139, type 0, instance id 0 lsn 9, checksum: 3118723984, change num 0, isEncrypted 0, isCompressed 0

unknown type 0

tail: change num: 0

DISK BLOCK DUMP END

*** 2024-07-30 10:18:53.922

Block dump from disk:

DISK BLOCK DUMP

unknown

head: id 0-140, type 0, instance id 0 lsn 9, checksum: 979551335, change num 0, isEncrypted 0, isCompressed 0

unknown type 0

tail: change num: 0

DISK BLOCK DUMP END

分析数据发现135的块中存在数据：

4、转换ROWID，查询数据内容

查看ROWID说明：ROWID UROWID | YashanDB Doc (yasdb.com)

对应：

dataoid 为2486

spaceid为4

fileid为0（同个表空间可能有多个数据文件）

blockid为135

dir为0

最终拼接的rowid为2486:4:0:135:0，根据rowid查询结果如下：