At 01:14 PM 12/4/2003, you wrote:
Hi Justin
Didn't know you were on the list
I'm usually about a week behind, so I don't get to participate very
often...
A properly formed hint will
cause the CBO to consider the
hinted path to be
less costly than it would otherwise consider it, but hints
Title: Message
I could notget Outlook to prefix your message properly -
grrr. Comments are at the top which may make reading them hard.I have
tried to setup a simple demo that hints are not 'suggestions' sorry if this
becomes long - this is all 9.2 but should apply to 8i and later versions
Hi Justin
Didn't know you were on the list
A properly formed hint will cause the CBO to consider the
hinted path to be
less costly than it would otherwise consider it, but hints do
not force a
query to use that particular plan. For a moderately
complicated query,
you'd potentially
Btw, the one good use for plan stability stored outlines are poorly
written 3rd party applications, where you can't even add a hint to code. I
these cases you can compose a good execution plan yourself and set your
statement to use it.
Tanel.
- Original Message -
To: Multiple
Thanks for hint, I didn't know there's something like this bundled. Unfortunately,
when I tried to create outline I got error
The outline could not be viewed.
ORA-01405: fetched column value is NULL
I have create/alter/drop any outline privilege, I even tried it as dba, but no luck.
So, there
What is complicated about stored outlines? If you don't like those you
can always go back to the RBO.
Gudmundur
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Wartiak Rastislav
Sent: 2. desember 2003 08:44
To: Multiple recipients of list ORACLE-L
At 01:44 AM 12/2/2003, Wartiak Rastislav wrote:
my question is about the same, but more general. How can i force Oracle to
use my prefered way of explain plan and not use CBO's. I mean, apart from
stored outlines, it somehow seems to complicated. I would like to say what
order and join types
What's the objection to using stored outlines? That's the
Oracle-provided mechanism for forcing queries to use a particular
plan.
The problem is that I have to first analyze tables with real data for CBO to create
plan I find useful (like using specific indexes etc.) and then to store it.
AFAIK RBO cannot be used for partitioned tables, not talking about the fact that RBO
might not be supported in future versions.
What is complicated about stored outlines? If you don't like those
you can always go back to the RBO.
Gudmundur
-Original Message-
From: [EMAIL
] [mailto:[EMAIL PROTECTED] On
Behalf Of Wartiak Rastislav
Sent: 2. desember 2003 09:39
To: Multiple recipients of list ORACLE-L
Subject: RE: Plan stability
AFAIK RBO cannot be used for partitioned tables, not talking
about the fact that RBO might not be supported in future versions
, the best way I know of to force the CBO to use your
plan is stored outlines.
Gudmundur
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of Wartiak Rastislav Sent: 2. desember 2003 09:39
To: Multiple recipients of list ORACLE-L
Subject: RE: Plan
ORACLE-L
Subject: RE: Plan stability
AFAIK RBO cannot be used for partitioned tables, not talking
about the fact that RBO might not be supported in future versions.
What is complicated about stored outlines? If you don't like those
you can always go back to the RBO.
Gudmundur
Notes in-line
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
The educated person is not the person
who can answer the questions, but the
person who can question the answers -- T. Schick Jr
One-day tutorials:
http://www.jlcomp.demon.co.uk/tutorial.html
Three-day seminar:
see
The biggest problem with hints is that you cannot
specify a full set - in particular there is no effective
way to handling unnesting of subqueries.
For simple cases, you can put the tables in the
main query in the 'correct' order and use the
ORDERED hint, then name the indexes and
join
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