Re: Database Performance

Kasi:

    Oracle has changed their opinion on multiple extents being a problem. They no longer think it's much of an issue, although they once warned against throwing extents. Specifically, 7 to 10 extents in and of itself is not a problem. You'll have to look elsewhere. Have you checked chained rows?

Van

Brian Peasland <peasland_at_edcmail.cr.usgs.gov> wrote in message news:39575A7E.A767D30D_at_edcmail.cr.usgs.gov...
> Kasi,
>
> 7-10 extents for a segment is not that many extents. If you are doing
> full table scans, then you will search 50,000 records no matter if it is
> in one extent, or many extents. It's not uncommon for some of my tables
> to have around 1,000 extents without seriously impacting performance.
> Many DBAs are subscribing to the theory that multiple extents are not
> that serious of a problem. There are many reasons for this which I won't
> go into here.
>
> The first place that you should look into is to follow Jacques post and
> tune your SQL statements.
>
> HTH,
> Brian
>
>
> kskasi_at_hotmail.com wrote:
> >
> > Hello everyone
> >
> > The problem is that, the biggest table we have in our system has got
> > only about 50,000 records. But the system seems to be slow even with
> > those many records. Our DBA feels that enough space wern't alloted to
> > the tables and they might be sitting in multiple extends. I had a look
> > at the extends and I did notice that there are about 7 - 10 extends for
> > the big table and some of the indexes. According to him, if there are
> > more number of extends then oracle has to search through all the extends
> > which takes more time. I had a look at Oracle documentation and it
> > dosen't mention about this at all. I just want a second opinion on this
> > before I drop the tables and recreate them with enough space. I guess I
> > can rebuild the indexes with enough space but the tables has to be
> > dropeed and reloaded. Any help would be appreciated
> >
> > Cheers...kasi
>
> --
> ========================================
> Brian Peasland
> Raytheons Systems at
> USGS EROS Data Center
> These opinions are my own and do not
> necessarily reflect the opinions of my
> company!
> ========================================
Received on Mon Jun 26 2000 - 00:00:00 CDT