Re: Strange: after TRUNCATE I noticed the obj# differs in a segment hdr dump

It's the data_object_id (if you look in dba_objects). or dataobj# in obj$. The obj# is indexed, and identifies an object logically, the dataobj# is not indexed, and identifies the physical storage of the data in the logical object.

For a simple table, the two start off the same, but if you move the table, or truncate the table, then a new data object id is generated for the effectively new physical location.

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"Spendius" <spendius_at_muchomail.com> wrote in message
news:aba30b75.0309180657.595cb7ee_at_posting.google.com...


> I've noticed that the line

> > Map Header:: next 0x... #extents: 1  obj#: 23896 flag:...

>

> in a trace file (resulting from an ALTER SYSTEM DUMP DATAFILE

> command) changes and that the value of obj# is incremented (yet

> nothing's changed in SYS.OBJ$ or DBA_OBJECTS -fortunately-).

>

> Does anyone know where does this value come from/where it's

> stored ? (when I do SELECT name FROM sys.obj$ WHERE obj#=newValue

> I get "no rows selected")

>

> Thanks.