Re: Create 12c or 18c database in traditional architecture
Date: Wed, 29 Aug 2018 13:23:51 +0000
Message-ID: <AM0PR10MB24500A9ECAC2AFB325CF21DA85090_at_AM0PR10MB2450.EURPRD10.PROD.OUTLOOK.COM>
Personally I think multi-tenant a decent feature but it is cost prohibitive for what you get in return.
There's not enough compelling functional reasons to migrate to the single-PDB model... except for 2 items:
- What are Oracle using in the Cloud? PDB's. It's only a small percentage of the Oracle installed base at present but that will grow and become the norm.
- What do Oracles regression tests run against? I don't know the answer to this but I suspect that they mostly run against PDB's now. It's like the old Block Size argument - which block size should you use (answer: 8k only - unless you have a proven case to change size). Oracle regression tests run against 8k and 16k block sizes. There are few (if any) regressions against 32k block sizes in a normal regression run, although that's changing apparently.
I'd imagine its the same with PDB's (and I'm now going to try to find out, unless someone on here knows?) If all of the regressions run against the multi-tenant code path, you should be using the single-PDB model as it'll have fewer bugs.
I see about a 20% adoption rate at my clients of single PDB at the moment, and nobody rushing to embrace it except Tim 😎
Neil Chandler
Database Guy.
From: oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> on behalf of niall.litchfield_at_gmail.com <niall.litchfield_at_gmail.com> Sent: 29 August 2018 12:21
Cc: ORACLE-L
Subject: Re: Create 12c or 18c database in traditional architecture
Hi Yong
We've gone with the traditional architecture so far, the primary reason for this is that administration scripts and utilities that use ORACLE_SID and/or TWO_TASK will all require rewriting to ensure they continue to work. Frankly, we have an incomplete handle on all the available scripts on our several hundred Oracle servers and almost no view of the ad-hoc etc scripts that development teams may have placed on our DB servers. Certifying and communicating the change is also a not insignificant effort for a pretty small Engineering team. That said our aim is definitely to migrate to the PDB architecture the 12.2 "family" of releases timescale. We absolutely do not want to be in a position where we *have* to move faster than we actually can! Similarly, we've not looked yet at FlexASM but we will do in a potential feature release.
I don't see single PDB being buggier than the traditional release (I can see that there will be bugs around the new features of multi-tenant) and its not true that there's no MGMTDB in a traditional architecture (and from 12.1.0.2 it will be a single instance pdb ! ).
On Tue, Aug 28, 2018 at 5:02 PM Yong Huang <dmarc-noreply_at_freelists.org<mailto:dmarc-noreply_at_freelists.org>> wrote: When creating a 12c or 18c database without the multitenancy license, I can (1) create the database with one CDB and only one PDB, or (2) create the database in the traditional or non-CDB architecture. The advantage of (2) is possibly less buggy, less overhead (no mgmtdb on RAC for instance), and slightly easier management. But the disadvantage is that Oracle does not recommend it and that "(t)he non-CDB architecture was deprecated in Oracle Database 12c. It can be desupported and unavailable in a release after Oracle Database 19c."
Short of a formal survey, I'd like to know which option you all have chosen. Thank you!
Yong Huang
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Niall Litchfield
Oracle DBA
http://www.orawin.info
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http://www.freelists.org/webpage/oracle-l
Received on Wed Aug 29 2018 - 15:23:51 CEST