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Do you practice database downgrades?

BPeaslandDBAJan 28 2016 — edited Feb 24 2016
Do you practice database downgrades?
Yes: 95
No: 580

Comments

my comment did not approved by some one

unknown-1040115 Feb 24 2016

If your answer is yes, please leave comment on which version you downgraded to and why. @"BPeaslandDBA"

BPeaslandDBA Feb 24 2016

If your answer is yes, please leave comment on which version you downgraded to and why. @"BPeaslandDBA"

I haven't had a need to perform an actual database downgrade, but I have practiced plenty. Practicing database downgrades is all about risk management. You can read more of my thoughts here. Complacency leads to: Risk Becomes Reality » Peasland Database Blog

While I haven't needed to downgrade a prod database, I was close to it last year after upgrading from 11.2.0.4 to 12.1.0.2 due to numerous performance issues. I documented those here: http://www.peasland.net/2015/11/16/dynamic-sampling-killing-me-in-12c/

and here: Adaptive Dynamic Stats Kills Performance in 12.1.0.2 RAC » Peasland Database Blog

Hemant K Chitale Feb 24 2016

I haven't had a need to perform an actual database downgrade, but I have practiced plenty. Practicing database downgrades is all about risk management. You can read more of my thoughts here. Complacency leads to: Risk Becomes Reality » Peasland Database Blog

While I haven't needed to downgrade a prod database, I was close to it last year after upgrading from 11.2.0.4 to 12.1.0.2 due to numerous performance issues. I documented those here: http://www.peasland.net/2015/11/16/dynamic-sampling-killing-me-in-12c/

and here: Adaptive Dynamic Stats Kills Performance in 12.1.0.2 RAC » Peasland Database Blog

Unfortunate that this poll hasn't received a sufficient (statistically significant in relation to the number of DBAs on community.oracle.com who might have done upgrades in the past 1 year ?) number of responses.

Hemant K Chitale

Pavan Kumar Feb 24 2016

Hi,

To be honest ,some times I do - due some issues the downgraded from 12c to 11.2.0.4 (recursive testing of upgrade performance path- which was taking huge time)

Way back in 10 to 11 ( I did tested), from their on-wards I tried to test downgrade when time permits

Couple of times grid downgrade (due to issues)

- Pavan Kumar N

Richard Harrison . Feb 26 2016

Similar to Brian we've tested a few downgrades but never had to actually do it.

It's not something we do all the time - its mainly aimed at the first few upgrades of a certain version we do to prove that its possible rather than testing every single one that could be done - it's a balance between the amount of effort and the risk of something going wrong.

For example we'd check 12.1->11.2, 11.2-> 11.1 etc - we wouldn;t really bother with checking 11.2.0.4->11.2.0.3 so much

spiderwoman Mar 23 2016

I haven't had a need to perform an actual database downgrade, but I have practiced plenty. Practicing database downgrades is all about risk management. You can read more of my thoughts here. Complacency leads to: Risk Becomes Reality » Peasland Database Blog

While I haven't needed to downgrade a prod database, I was close to it last year after upgrading from 11.2.0.4 to 12.1.0.2 due to numerous performance issues. I documented those here: http://www.peasland.net/2015/11/16/dynamic-sampling-killing-me-in-12c/

and here: Adaptive Dynamic Stats Kills Performance in 12.1.0.2 RAC » Peasland Database Blog

"due to numerous performance issues."

So before upgrade there was no extensive testing in loadtest environment?

Typically we go from dev-uat-loadtest-prod, so kinks are sorted out before "go", "no-go"

Thanks,

spiderwoman Mar 23 2016

Unfortunate that this poll hasn't received a sufficient (statistically significant in relation to the number of DBAs on community.oracle.com who might have done upgrades in the past 1 year ?) number of responses.

Hemant K Chitale

"Unfortunate that this poll hasn't received a sufficient (statistically significant in relation to the number of DBAs on community"

At least we got to vist peasland and view the blog

BPeaslandDBA Mar 23 2016

"due to numerous performance issues."

So before upgrade there was no extensive testing in loadtest environment?

Typically we go from dev-uat-loadtest-prod, so kinks are sorted out before "go", "no-go"

Thanks,

Yes, it was loadtested by another team. However, no issues were reported by them. And now its too late to know for sure if those issues showed up and no one noticed or if they didn't show up at all.

Hi,

Most of the people have done it for testing purpose only , even i did the same , In organization , never saw this type of requirement , either they are in non supported version by Oracle eg:- Oracle 9i, Oracle8i or They are upgraded due to support expired.

Regards,

Shivendra Narain Nirala

ZeeShan Ali Shoban Apr 1 2016

No

oraLaro Apr 5 2016

testing a lot,  we're going to 12 from 11.2.0.4 in a test environment in prep for the 12 upgrade.    Very time consuming.   lot of bugs encountered once we go back.  And theyre new bugs as we can see from this thread, very few practice them.

Geert Gruwez Apr 21 2016

i've actually done a prod downgrade from 11.2.0.4.10 to 11.2.0.4.8

noticing a patch is removed from the downloads after an upgrade can be a sign for an upcoming downgrade

rcc50886 May 25 2016

I recently tested the downgrade of 12.1.0.2 to 11.2.0.4. We encountered multiple bugs and ended up reconfiguring the 11.2.0.4 GI. It was a good learning experience.

Mudasir Hakak Jul 12 2016

Did the dowgrade as part of rollback plan, didnt really need it though.

wbriceno Jul 12 2016

Yes, I did downgrade one time because an application is not certified to work with an Oracle Database version; and have done some only for practice.

regards

William Robertson Nov 25 2016

This poll has been here since January. It's now almost December. How much longer will it take up the front page?

Geert Gruwez Nov 25 2016

This poll has been here since January. It's now almost December. How much longer will it take up the front page?

until Jezus Christ answers ?

Geert Gruwez Jun 30 2017 — edited on Jun 30 2017

well, i'm not gonna practice this, i'm actually having to do it for 12.1.0.2 on windows

downgrading to 161018

why ?

we experienced complete hangs on 170117

we have to use deprecated procedures cause the non-deprecated procedures seem not to work on patch in 170418

Not downgraded to an older version, but just worked with the compatible parameter. One time we fund out that performance downgraded dramaticaaly after upgrade in case of different sort actions. After changing the compatible setting, this issue was resolved and still working on a supported database engine.

user13030215 Jul 18 2017

I would never bother with that. Remove and re-do, or upgrade later.

Laury Nov 1 2018

I have been involved only once, just after an upgrade. No new functionality was added on it. I used the owngrade script, and it was OK.

The reason for the decision of the downgrade was not related to the database itself, but rather one of the underlying application.

mariam.kupa Jun 14 2019

Only once. In 10g database. Because of the bug in newer version.

In other cases, I always do my best to resolve the issue instead of doing downgrade and it always works. 

Only once. In oracle 12c, because of performance issues.

Unfortunately, One of my customers was forced to go to a single environment for a short time due to a performance problem in ORACLE RAC 12c.

After improving query performance so back to oracle RAC 12c.

Hi,

Yes i did the upgrade from Oracle 11g(11.2.0.1) to Oracle 11g(11.2.0.4) by using the manual method upgrade instead of DBUA.

Which one do you recommend to do for production database as best practice.

Warm Regards,

Mir Sayeed Hassan

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Added on Jan 28 2016
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