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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Oracle position on hints (talking about bind variables)
My first consideration with regards to bind variables is to consider the
cost of parsing the query. After all the benefit of bind variables (or at
least a major one) is to reduce the number of parses required. If the
query is going to be executed so rarely that the parse cost (a fraction of
a second typically) isn't significant then there appears to be little
benefit.
I think bind variables are most useful in OTLP where the same query gets fired again and again (especially when you have hundreds of client connections). At the other extreme (a batch query executed once per day) they aren't required. Therefore my approach tends to be "is the query going to be executed very frequently - if so then look at using bind variables on the values that will change".
Regards,
Mark.
Jared.Still_at_ra
disys.com To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
Sent by: cc:
root_at_fatcity.c Subject: RE: Oracle position on hints
om
11/03/2003
05:09
Please respond
to ORACLE-L
Well, I wouldn't say you should *always* use bind variables.
Many situations in a database warehouse preclude that.
Potentially long running queries may need to have literals to help the CBO make the right choice.
Star transforms don't work with bind variables, and histograms can't be used with bind variables.
Jared
"Nicoll, Iain" <IAIN.D.NICOLL_at_saic.com>
Sent by: root_at_fatcity.com
03/08/2003 06:23 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
cc:
Subject: RE: Oracle position on hints
Given the attitude of most dba's that you should always use bind variables
where possible I can't see how you'd cope with skewed data without them.
Most developers should know a databases's data better than the optimiser
and
certainly when building queries it's always worthwhile seeing where data
is
being most effectively filtered.
There are lots of mature systems out there where the data characteristics are unlikely to change much and for most in-house developers you're never going to have to think about portability but always about performance.
Iain Nicoll
-----Original Message-----
Sent: 07 March 2003 16:04
To: Multiple recipients of list ORACLE-L
Hi,
Does Oracle have an official position on hints ? Will they go away as the optimiser is becoming bettre or they are there to stay ?
TIA Stephane Paquette
Administrateur de bases de donnees
Database Administrator
Standard Life
www.standardlife.ca
Tél. (514) 925-7187
stephane.paquette_at_standardlife.ca <mailto:stephane.paquette_at_standardlife.ca
>
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Nicoll, Iain INET: IAIN.D.NICOLL_at_saic.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: Jared.Still_at_radisys.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<---->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Privileged/Confidential information may be contained in this message. If you are not the addressee indicated in this message (or responsible for delivery of the message to such person), you may not copy or deliver this message to anyone. In such case, you should destroy this message and kindly notify the sender by reply e-mail or by telephone on (61 3) 9612-6999. Please advise immediately if you or your employer does not consent to Internet e-mail for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of Transurban City Link Ltd shall be understood as neither given nor endorsed by it. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<---->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Mark Richard INET: mrichard_at_transurban.com.au Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Mon Mar 10 2003 - 21:18:36 CST
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