SQL SERVER 2008 R2 DBCC PAGE PUZZLED

Question

i did a test about DBCC IND and DBCC page . Engine: SQL Server 2008

Script:

CREATE TABLE dbo.t2
(
ID int,
Col1 varchar(10),
Col2 varchar(20)
);


INSERT INTO dbo.t2 SELECT 1,REPLICATE('a',10),REPLICATE('b',10)


DECLARE @DBID int,@TableID int;
SELECT @DBID=DB_ID(),@TableID=OBJECT_ID('dbo.t2');
DBCC IND(@DBID,@TableID,-1)

--this shows : 1 274 1 278 1307151702 0 1 72057594039107584 In-row data 1

DBCC TRACEON (3604)
--DBCC PAGE (@DBID, 1,22,3)
--then dump the page info
DBCC PAGE(@DBID, 1,274,1)

shows:

DATA:

Slot 0, Offset 0x60, Length 51, DumpStyle BYTE

Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP VARIABLE_COLUMNS VERSIONING_INFO Record Size = 51 Memory Dump @0x000000000F7EA060

0000000000000000: 70000800 01000000 03000002 001b0025 †p..............% 0000000000000010: 00616161 61616161 61616162 62626262 †.aaaaaaaaaabbbbb 0000000000000020: 62626262 62000000 00000000 00310000 †bbbbb........1.. 0000000000000030: 00000†††††††††††††††††††††††††††††††...

OFFSET TABLE:

Row - Offset 0 (0x0) - 96 (0x60) i try to explain:

byte one 0x70 01110000

BIT 0: SQL SERVER 2005/2008

BIT 1-3 :PRIMARY DATA

BIT 4 : HAS NULL

BIT 5:HAS VAR

BIT 6:NOT USED

BIT 7: NOT GHOST

Second Byte

0x00 : NOT USED

Thrid Byte

0x0008 :offset 8

the fix length int ,i got value 1

then next byte

0300 : 3 columns

00 : not null

0002 :2 columns

var column endoffset 0x001B (i got value aaa....)

var column end offset 0x0025 (i got value bbbb...)

but ,i don's know the meaning about last bytes....

please help me ,thks a lot

Answer 1

It's the 14-byte versioning tag [timestamep, pointer into tempdb].