Re: increasing COMPATIBLE parameter
- From: MARK BRINSMEAD <mark.brinsmead@xxxxxxxxx>
- To: JEREMY.SHEEHAN@xxxxxxxxxxxxxxxxx
- Date: Wed, 25 Mar 2015 11:47:57 -0400
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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