IDS Forum

Re: How to disable cache/buffer when running t....

Posted By: rroussey@comcast.net
Date: Wednesday, 8 April 2009, at 3:49 p.m.

In Response To: RE: How to disable cache/buffer when running t.... (Scott MacKenzie)

Just like a mathematical proof in college:

"assume the opposite is true. to prove it wrong......"

Bob

----- Original Message -----
From: "Scott MacKenzie" <scottm@dinecollege.edu>
To: ids@iiug.org
Sent: Wednesday, April 8, 2009 10:15:21 AM GMT -05:00 US/Canada Eastern
Subject: RE: How to disable cache/buffer when running t.... [15483]

To add a third solution: Run a MASSIVE select on other tables before your test
query - that way the buffer cache will fill with other tables' data first. And
your query will be facing the same up-hill battle every time you run it!

-ScottM

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
Andreas.KUTSCHE@spar.at
Sent: Wednesday, April 08, 2009 3:28 AM
To: ids@iiug.org
Subject: AW: How to disable cache/buffer when running t.... [15479]

Hi,

IDS doesn't cache a result set but it caches the data/index pages needed to
create the result (if the buffer cache is reasonable large).

If you run a query for the first time (and no other query has requested that
data too) IDS has to read the tables/indexes from disk. The following query
executions will find all or some of the needed tables/indexes in the buffer
cache (memory).

There are two solutions:
1)
Run all of your test queries at least two times and compare only the second
run times.
2)
Start IDS with a very small buffer cache.

Regards,
Andreas

-------------------------------------------
SPAR sterreichische Warenhandels-AG
Hauptzentrale
A - 5015 Salzburg, Europastrasse 3
FN 34170 a

Tel: +43 662 4470 24223
Mobile: +43 664 6259575
E-Mail: Andreas.KUTSCHE@spar.at
Internet: http://www.spar.at

Wichtiger Hinweis: Der Inhalt dieser E-Mail kann vertrauliche und rechtlich
geschtzte Informationen, insbesondere Betriebs- oder Geschftsgeheimnisse,
enthalten, zu deren Geheimhaltung der Empfnger verpflichtet ist. Die
Informationen in dieser E-Mail sind ausschlielich fr den Adressaten
bestimmt. Sollten Sie die E-Mail irrtmlich erhalten haben so ersuchen wir
Sie, die Nachricht von Ihrem System zu lschen und sich mit uns in Verbindung
zu setzen.
ber das Internet versandte E-Mails knnen leicht manipuliert oder unter
fremdem Namen erstellt werden. Daher schlieen wir die rechtliche
Verbindlichkeit der in dieser Nachricht enthaltenen Informationen aus. Der
Inhalt der E-Mail ist nur rechtsverbindlich, wenn er von uns schriftlich
besttigt und gezeichnet wird.
Sollte trotz der von uns verwendeten Virus-Schutzprogramme durch die Zusendung
von E-Mails ein Virus in Ihre Systeme gelangen, haften wir nicht fr evtl.
hieraus entstehende Schden.
Wir danken fr Ihr Verstndnis.

Important notice: The contents of this e-mail may contain confidential and
legally protected information that is in particular related to operational and
trade secrets, which the recipient is obliged to treat as confidential. The
information in this e-mail is made available exclusively for use by the
addressee. In the event that the e-mail may have been sent to you in error, we
would ask you to kindly delete this communication from your system and to
contact us.
E-mails sent via the Internet can be easily manipulated or sent out under
someone else's name. We therefore do not accept legal liability for the
information contained in this communication. The contents of the e-mail are
only legally binding if they have been confirmed and signed by us in writing.
If, in spite of our using Antivirus protection software, a virus may have
penetrated your system through the sending of this e-mail, we do not accept
liability for any damage that may possibly arise as a result of this.
We trust that you appreciate our position.

-------------------------------------------
-----Ursprngliche Nachricht-----

Von: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] Im Auftrag von jak aka
Gesendet: Mittwoch, 8. April 2009 11:19
An: ids@iiug.org
Betreff: How to disable cache/buffer when running the s.... [15478]

Hello ,

When I run a query , for the 1st time the query will take xx minute (ex. 10
minute) but if I run this query again , it will take only y minute (ex. 1
minute). I think IDS keep the result set in buffer/cache . When I run again ,
IDS map this query to the buffer/cache and retrieve the pre-run result set to
me.

My question is "how to disable this feature or to disable buffer/cache" ?

Because I 'd like to tune query and want to get the actual time using by this
query (after changing something such as index, statistics) but I cannot get
the actually time if I run this query again (not first time).

Best regards,
Jakkrit A.

Messages In This Thread

• How to disable cache/buffer when running the same
  jak aka -- Wednesday, 8 April 2009, at 5:18 a.m.
  • AW: How to disable cache/buffer when running the s
    Andreas.KUTSCHE@spar.at -- Wednesday, 8 April 2009, at 5:27 a.m.
    • RE: How to disable cache/buffer when running t....
      Scott MacKenzie -- Wednesday, 8 April 2009, at 10:15 a.m.
      • Re: How to disable cache/buffer when running t....
        rroussey@comcast.net -- Wednesday, 8 April 2009, at 3:49 p.m.
  • RE: How to disable cache/buffer when running the s
    Mark Tyrer -- Wednesday, 8 April 2009, at 5:37 a.m.
  • Re: How to disable cache/buffer when running the s
    Art Kagel -- Wednesday, 8 April 2009, at 11:36 a.m.

IDS Forum is maintained by Administrator with WebBBS 5.12.