Re: Full table scan: what order?

On Sat, 12 Jan 2002 17:32:10 GMT, j.w.vandijk_at_hetnet.nl (Jaap W. van Dijk) wrote:

>I've written a script (or at least tried) that shows me how far a full
>table scan has progressed for a session. I can determine the block the
>session is currently reading by retrieving p1 (file_id) en p2
>(blocknumber) from v$session_wait in case of event 'db file scattered
>read'. But in which order does Oracle read the blocks?
>- file_id,extent_id?
>- extent_id?
>Is there a difference between Oracle 7 and Oracle 8?
>I've tried both assumptions but the result my script is giving is
>never a steady increasing value.

In physical order, as far as I know. As you can verify in dba_extents the extent_id is unique across the object, and doesn't start numbering again for a new file.
The only other alternative looks like file_id, block_id You can easily check that of course

Apart from the rowid having changed there shouldn't be any difference between 7 and 8 in this respect.

Hth

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Sat Jan 12 2002 - 12:21:37 CST