Re: Tablespace Usage and Performance

On Nov 9, 1:25 pm, Robert Klemme <shortcut..._at_googlemail.com> wrote:
> On 08.11.2008 21:48, DA Morgan wrote:
>
>
>
>
>
> > Robert Klemme wrote:
> >> On 08.11.2008 02:49, DA Morgan wrote:
> >>> Dereck L. Dietz wrote:
> >>>> Oracle 10g 10.2.0.3
> >>>> Windows 2003 Server
>
> >>>> I have someone who made the following statement:
>
> >>>> "any time a tablespace is > 85% [ of capacity ] we experience
> >>>> performance degragation".
>
> >>>> Is there any validity in that or not?
>
> >>>> Thanks
>
> >>> Not!
>
> >> Hmm, I lean more towards Joel.  After all, the statement is just an
> >> observation, which we can't really question.  The interesting bit is
> >> to find out what caused this observation.  There may be a common root
> >> for both phenomena (for example, heavy insert activity at end of month
> >> just before old data is purged, leading to tablespaces filling up AND
> >> queries being slow).  But of course, there is by far too many detail
> >> to only start guessing about something like that.  We do not even know
> >> what "performance degradation" means.  Is it queries, inserts, backup
> >> etc.? Just one statement or multiple? ...
>
> > My point in the simplistic answer is that there may be other things
> > going on but there is no 1:1 relationship between available space
> > and performance. Could a lack of space mean that there are other
> > issues related to performance? Of course. But you can not draw a
> > straight line that corresponds with the question asked by the OP.
>
> I agree with regard to the straight line.  I just felt the answer was
> probably a bit too simplistic in this case and was trying to avoid
> subsequent miscommunications e.g.
>
> "any time a tablespace is > 85% [ of capacity ] we experience
> performance degragation".
>
> "Can't be."
>
> "Are you kidding me?  Look at these figures: " [EM pops up] "tablespace
> is full, query slow."
>
> ...
>
> And yes, I confess, I did enjoy the nitpicking.  But I felt it could
> help speak out the unspoken so I did not resist the "temptation". :-)
>
> Kind regards
>
>         robert- Hide quoted text -
>
> - Show quoted text -

>> " [EM pops up] "tablespace is full, query slow." <<

What this example proves is that too many of the programmers Oracle hires to write its applications do not understand how Oracle works.

HTH -- Mark D Powell -- Received on Wed Nov 12 2008 - 11:02:48 CST