Where is underlying data for IDENT_CURRENT stored?

Question

Ok.. a silly litte question. Honestly, it's not important for what I'm doing, but I've just gotta know!

I created a table with an IDENTITY(1,1) column. I insert no rows. I used

DBCC CHECKIDENT(table, RESEED, 10000)

I run the following:

SELECT IDENT_CURRENT('table')
SELECT last_value, seed_value
FROM sys.identity_columns
WHERE [object_id] = OBJECT_ID('table');

The first returns 10000. The second returns NULL, 1 (the original seed value).

Where is 10000 stored?

Answer 1

This is not documented and is subject to change but it is stored in the left most X bytes of idtval in sys.syscolpars.

The value of X depends on the datatype of the underlying column. For an int it is 4.

Immediately after running

CREATE TABLE [table1](Foo int IDENTITY)

The following query (only can be executed using the DAC) ...

SELECT *,
       CAST(CAST(REVERSE(LEFT(idtval, 4)) AS BINARY(4)) AS INT)
FROM   sys.syscolpars
WHERE  id = OBJECT_ID('table1') 

... Returns

After running

DBCC CHECKIDENT([table1], RESEED, 10000)

It returns