Hint/Directive

Raymond Bell

Hint/Directive
Ah, I geddit now. Ta. A shame we've propagated the poor naming of
another DBMSs feature, but there you go. You could argue the marketing
of technology is more important than the technology itself; certainly
was the case for Betamax (which, I believe, is still used by TV
companies around the world), OS/2 and HD DVD. But that's a discussion
for another day/forum.

Cheers Troy,


Raymond
PS: Actually, maybe Hint isn't such a bad term. I mean, if the hint
coded can't actually be used (eg. use IX1 to access the data when
there's no such index) then DB2 can't do as instructed. Or, with
apologies to Mr. Kubrick, 'I'm sorry Hint, I'm afraid I can't do that'.

-----Original Message-----
From: DB2 Data Base Discussion List [mailto:[login to unmask email] On
Behalf Of Troy Coleman
Sent: 17 January 2009 06:27
To: [login to unmask email]
Subject: Re: [DB2-L] Avoid index usage

I assumed the name "hint" was given because that is what ORACLE uses.
From a marketing/sales view we want to make sure the customer can check

the feature off for DB2 and ORACLE.

Troy


<snip>
>

______________________________________________________________________

* IDUG 2009 Melbourne, Australia * 18-20 March * http://IDUG.ORG/Events
*
______________________________________________________________________




IDUG.org was recently updated requiring members to use a new password.
You should have gotten an e-mail with the temporary password assigned to
your account. Please log in and update your member profile. If you are
not already an IDUG.org member, please register at
http://www.idug.org/component/juser/register.html

______________________________________________________________________

* IDUG 2009 Denver, CO, USA * May 11-15, 2009 * http://IDUG.ORG/Events *
______________________________________________________________________




IDUG.org was recently updated requiring members to use a new password. You should have gotten an e-mail with the temporary password assigned to your account. Please log in and update your member profile. If you are not already an IDUG.org member, please register at http://www.idug.org/component/juser/register.html

Gerald Hodge

Re: Hint/Directive
(in response to Raymond Bell)
The person to ask is David Schwartz from IBM as he managed the project. He
is retired now.

Gerald Hodge
HLS Technologies, Inc.
www.hlstechnologies.com


-----Original Message-----
From: DB2 Data Base Discussion List [mailto:[login to unmask email] On Behalf
Of Bell, Raymond
Sent: Monday, January 19, 2009 6:16 AM
To: [login to unmask email]
Subject: Re: [DB2-L] Hint/Directive

Ah, I geddit now. Ta. A shame we've propagated the poor naming of
another DBMSs feature, but there you go. You could argue the marketing
of technology is more important than the technology itself; certainly
was the case for Betamax (which, I believe, is still used by TV
companies around the world), OS/2 and HD DVD. But that's a discussion
for another day/forum.

Cheers Troy,


Raymond
PS: Actually, maybe Hint isn't such a bad term. I mean, if the hint
coded can't actually be used (eg. use IX1 to access the data when
there's no such index) then DB2 can't do as instructed. Or, with
apologies to Mr. Kubrick, 'I'm sorry Hint, I'm afraid I can't do that'.

-----Original Message-----
From: DB2 Data Base Discussion List [mailto:[login to unmask email] On
Behalf Of Troy Coleman
Sent: 17 January 2009 06:27
To: [login to unmask email]
Subject: Re: [DB2-L] Avoid index usage

I assumed the name "hint" was given because that is what ORACLE uses.
From a marketing/sales view we want to make sure the customer can check

the feature off for DB2 and ORACLE.

Troy


<snip>
>

______________________________________________________________________

* IDUG 2009 Melbourne, Australia * 18-20 March * http://IDUG.ORG/Events
*
______________________________________________________________________




IDUG.org was recently updated requiring members to use a new password.
You should have gotten an e-mail with the temporary password assigned to
your account. Please log in and update your member profile. If you are
not already an IDUG.org member, please register at
http://www.idug.org/component/juser/register.html

______________________________________________________________________

* IDUG 2009 Denver, CO, USA * May 11-15, 2009 * http://IDUG.ORG/Events *
______________________________________________________________________




IDUG.org was recently updated requiring members to use a new password. You
should have gotten an e-mail with the temporary password assigned to your
account. Please log in and update your member profile. If you are not
already an IDUG.org member, please register at
http://www.idug.org/component/juser/register.html

______________________________________________________________________

* IDUG 2009 Denver, CO, USA * May 11-15, 2009 * http://IDUG.ORG/Events *
______________________________________________________________________




IDUG.org was recently updated requiring members to use a new password. You should have gotten an e-mail with the temporary password assigned to your account. Please log in and update your member profile. If you are not already an IDUG.org member, please register at http://www.idug.org/component/juser/register.html

Patrick Bossman

Re: Hint/Directive
(in response to Gerald Hodge)
Hello,
I asked my friend who developed optimization hints and he said he just
called them hints and that was that.

I've always thought optimization hints are a valuable tool to have in the
DBAs toolbox. I agree that ideally the access paths would be rechecked
periodically - such as when the physical design changes or when you upgrade
to a new release.

I have an old presentation on optimization hints here which documents some
scenarios where we recommend they are used.
One example: Skew which would require REOPT(ALWAYS) to recognize, but
REOPT(ALWAYS) overhead is prohibitive.

ftp://ftp.software.ibm.com/software/data/db2/zos/presentations/performance/optimization-hints-2006-bossman.pdf

We want customers to have efficient and stable performance and optimization
hints are one useful tool in this area.

Best regards,
Pat Bossman

______________________________________________________________________

* IDUG 2009 Melbourne, Australia * 18-20 March * http://IDUG.ORG/Events *
______________________________________________________________________




IDUG.org was recently updated requiring members to use a new password. You should have gotten an e-mail with the temporary password assigned to your account. Please log in and update your member profile. If you are not already an IDUG.org member, please register at http://www.idug.org/component/juser/register.html