Hi,

Packages like perfstats require timed_statistics to be set to true for
calculating wait times. I'm think of setting this value to true at the
instance level. But does it make sense to have this value set true all the
time? Does this have an impact on performance?? Should I only use this at
the session level when required?

Thanks for any info,
Cookie.

Hi

My experience ...
timed_statistics=true takes approx. 10% of the performance.

time_statistics is a dynamic init.ora parameter (since 8i) and you can
change this parameter "on the fly" for the database.

I don't know, if you change time_statistics on session level, you gather all
time statistics that could be needed for a performance analysis.

Kind regards
Hernan



"Cookie Monster" <cookie.monster@somewhere.com> schrieb im Newsbeitrag
news:c1v38r$1n78pt$1@ID-82797.news.uni-berlin.de...
> Hi,
>
> Packages like perfstats require timed_statistics to be set to true for
> calculating wait times. I'm think of setting this value to true at the
> instance level. But does it make sense to have this value set true all
the
> time? Does this have an impact on performance?? Should I only use this
at
> the session level when required?
>
> Thanks for any info,
> Cookie.
>
>

"Cookie Monster" <cookie.monster@somewhere.com> wrote in message news:<c1v38r$1n78pt$1@ID-82797.news.uni-berlin.de>...
> Hi,
>
> Packages like perfstats require timed_statistics to be set to true for
> calculating wait times. I'm think of setting this value to true at the
> instance level. But does it make sense to have this value set true all the
> time? Does this have an impact on performance?? Should I only use this at
> the session level when required?
>
> Thanks for any info,
> Cookie.


Yes
No, except for HP-UX
No

Sybrand Bakker
Senior Oracle DBA

"Cookie Monster" <cookie.monster@somewhere.com> wrote in message
news:c1v38r$1n78pt$1@ID-82797.news.uni-berlin.de...
> Hi,
>
> Packages like perfstats require timed_statistics to be set to true for
> calculating wait times. I'm think of setting this value to true at the
> instance level. But does it make sense to have this value set true all
the
> time?

Yes. if you want to reduce the time spent by processes, you need to measure
the time spent by the processes. If you want to use the wait interface then
again you need the timing info.

> Does this have an impact on performance??

Yes. it is impossible to monitor a process without adding overhead. The real
question is does this have an *unacceptable* overhead. For most systems the
answer to this is no, the figure 10% that you were given is at the high end
of figures that I have seen (but there have been port-specific bugs so
checking metalink for your platform and version would be advisable).

> Should I only use this at
> the session level when required?

I'd always have it set. I don't know ahead of time where my problems will
be...


--
Niall Litchfield
Oracle DBA
Audit Commission UK

> My experience ...
> timed_statistics=true takes approx. 10% of the performance.

10%?!?!? That seems pretty high.... I'd say less than 1% in my
experience. As part of the "standards" I have for my databases, I set
TIMED_STATISTICS=TRUE in all instances! And I haven't seen any noticable
affects.

HTH,
Brian


--
================================================== =================

Brian Peasland
dba@remove_spam.peasland.com

Remove the "remove_spam." from the email address to email me.


"I can give it to you cheap, quick, and good. Now pick two out of
the three"

"Niall Litchfield" <n-litchfield@audit-commission.gov.uk> wrote in message
news:40436142$0$22391$ed9e5944@reading.news.pipex. net...
>
> I'd always have it set. I don't know ahead of time where my problems will
> be...
>


Bugger! You don't watch your BCHR?....

--
Cheers
Nuno Souto
wizofoz2k@yahoo.com.au.nspam

I agree. I always set it, and it only seems to take less than 1%.

Mark Simmons
Sr. Oracle DBA
Sabre-Holdings, Southlake, TX

Brian Peasland <dba@remove_spam.peasland.com> wrote in message news:<404364E1.BB27F33E@remove_spam.peasland.com>. ..
> > My experience ...
> > timed_statistics=true takes approx. 10% of the performance.
>
> 10%?!?!? That seems pretty high.... I'd say less than 1% in my
> experience. As part of the "standards" I have for my databases, I set
> TIMED_STATISTICS=TRUE in all instances! And I haven't seen any noticable
> affects.
>
> HTH,
> Brian
>
>
> --
> ================================================== =================
>
> Brian Peasland
> dba@remove_spam.peasland.com
>
> Remove the "remove_spam." from the email address to email me.
>
>
> "I can give it to you cheap, quick, and good. Now pick two out of
> the three"