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Re: How can I selec rows in physical order?

From: <sergey_s_at_my-deja.com>
Date: 2000/06/22
Message-ID: <8its47$l11$1@nnrp1.deja.com>#1/1

I am trying to go against a 2.5 billion row table and get a sample for some testing (maybe about a 100 rows). I wanted to get the first 100 rows and get them fast. The table is partitioned, there are some bitmap indexes, but getting stuff out of the table is not quick. I guess I can use hints (like FIRST_ROWS or something), but I don't know how much of an improvement in speed that will create. ROWNUM doesn't help in this situation because the rows are not in the rownum order, and going that route with 2.5 billion row table - you get tired of waiting.

So, that's where I am coming from. Hope this clarifies things.

Thank you for your help!

Sergey

In article <395257A9.E729E0A_at_euclidsys.com>,   Randy DeWoolfson <randy_at_euclidsys.com> wrote:
> if you do a select without any order by clause then you will get the
> rows as retrieved from the tablespace - is this what you mean by
> physical order?
>
> It would be a real chore (i think) to decode the ROWID psuedocolumn
 into
> some disk mapping of sectors (blocks really) and then order those
> somehow within tablespaces...
>
> hope this helps.
> randy
>
> sergey_s_at_my-deja.com wrote:
>
> > Does ROWNUM guarantee physical order of the rows in a table?
> > If not, how can I get rows out in their physical order?
> >
> > Thanks!
> >
> > Sergey
> >
> > Sent via Deja.com http://www.deja.com/
> > Before you buy.
>
>

Sent via Deja.com http://www.deja.com/
Before you buy. Received on Thu Jun 22 2000 - 00:00:00 CDT

Original text of this message

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