Re: playing with dbms_rowid

"Ed Stevens" <nospam_at_noway.nohow> wrote in message news:kaoj60l8iif2nikvapuk5vanp361s4qmme_at_4ax.com...
> Correction: Oracle 8.1.7.4
>
> On Tue, 30 Mar 2004 15:00:13 -0600, Ed Stevens <nospam_at_noway.nohow>
> wrote:
>
> >Oracle 8.1.4 on Win2k
> >
> >Created a test tablespace. LMT w/ uniform extents.
> >Created table and pk index in the new TS
> >Ran a PL/SQL loop to load the new table with test data.
> >
> >Then ran the following query:
> >
> >select supl_key "key",
> > dbms_rowid.rowid_block_number(rowid) "block",
> > dbms_rowid.rowid_row_number(rowid) "row"
> >from mytable
> >order by supl_key
> >/
> >
> >I was somewhat surprised to find that the lowest # block-id was 18.
> >Am I right in thinking that blocks 1 thru 17 are used for TS
> >management?

Let me guess. You are using 4K Oracle blocks?

You are close, but not quite.

One of those 17 blocks is the data file header block (SCNs and all that). The other 16 will indeed be the tablespace bitmap (16 blocks at 4K each makes 64K. All LMTs start out with 64K pinched for the bitmap in this way).

Regards
HJR

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