Re: increasing COMPATIBLE parameter
- From: "Mark J. Bobak" <mark@xxxxxxxxx>
- To: MARK BRINSMEAD <mark.brinsmead@xxxxxxxxx>
- Date: Wed, 25 Mar 2015 12:01:28 -0400
Also, if it becomes necessary, i.e., if setting compatible to 11.2.0.3.0
messes with some of your execution plans, you may be able to maintain
compatability at 11.2.0.3.0 and fix your optimizer issues with
optimizer_features_enabled...?
Just a thought....if it becomes necessary...
-Mark
On Wed, Mar 25, 2015 at 11:47 AM, MARK BRINSMEAD <mark.brinsmead@xxxxxxxxx>
wrote:
> I bet the database uses the optimizer though. :-)
>
> There are hundreds, maybe even thousands, of differences in the query
> optimizer between 10gR2 and 11gR2, and I expect the vast majority of those
> are suppressed when you run with COMPATIBLE=10.2.0.4
>
> You really should do a regression test before making this change,
> especially considering that it is a one-way thing. You can increase the
> value of COMPATIBLE, but you can *never* decrease it again. Not unless
> you are ready to do an export/import.
>
> Most likely, you will be perfectly okay. *LOTS* of people complete this
> upgrade without a hitch. But in the unlikely(?) case that you are not one
> of them, you'll probably want to show you did "due diligence" first.
>
> On Tue, Mar 24, 2015 at 5:15 PM, Sheehan, Jeremy <
> JEREMY.SHEEHAN@xxxxxxxxxxxxxxxxx> wrote:
>
>> It's been modified in a test instance for a few weeks but I didn't
>> change it. Someone else did and didn't document anything and they don't
>> remember if anything else was done. This is a very vanilla db. No ASM,
>> RAC.
>>
>> Thanks!
>>
>> Jeremy
>>
>> Sent from a phone
>>
>> *From:* Don Seiler <don@xxxxxxxxx>
>> *Sent:* Mar 24, 2015 4:55 PM
>> *To:* Sheehan, Jeremy
>> *Cc:* Oracle-L (oracle-l@xxxxxxxxxxxxx)
>> *Subject:* Re: increasing COMPATIBLE parameter
>>
>> This is an EXTERNAL email. Exercise caution. DO NOT open attachments
>> or click links from unknown senders or unexpected email.
>> ------------------------------
>>
>> I would be sure to test application behavior on a test/staging database
>> prior to doing this. But then again, that's solid advice for making any
>> change in a database.
>>
>> Sometimes behavior of various components can change with the compatible
>> parameter. I've seen it in ASM diskgroup compatible changes, for what its
>> worth.
>>
>> Don.
>>
>> On Tue, Mar 24, 2015 at 3:50 PM, Sheehan, Jeremy <
>> JEREMY.SHEEHAN@xxxxxxxxxxxxxxxxx> wrote:
>>
>>> Hello,
>>>
>>>
>>>
>>> I’m on 11.2.0.3 and am looking to update the COMPATIBLE parameter in a
>>> database from 10.2.0.4 to 11.2.0.3. I’ve searched pretty extensively (gone
>>> to page 3 of Google results and checked on MOS – 733987.1). Aside from
>>> taking a backup before making this change, are there any additional things
>>> I should look for or do after the change?
>>>
>>>
>>>
>>> Please let me know! Thanks in advance.
>>>
>>>
>>>
>>> Jeremy
>>>
>>
>>
>>
>> --
>> Don Seiler
>> http://www.seiler.us
>>
>
>
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