Comments on: Pluggable 12c

By: Kirill Loifman

Kirill Loifman — Mon, 25 Feb 2013 15:01:05 +0000

If somebody are interested still in 12c Pluggable Database insights, read here a few articles:
http://www.dadbm.com/2013/02/oracle-12c-pluggable-database-plug-unplug-and-clone/

– Kirill

By: Jonathan Lewis

Jonathan Lewis — Thu, 13 Dec 2012 10:54:48 +0000

Jakub,

Again, a set of good questions to ask (either of the salesman, or as you design your proof of concept).
The SCN thing is interesting – but thinking about RAC and Distributed systems, they re-syncronize all the time anyway – having to put all the databases in one basket for a small improvement in synchronisation may be too much risk for too little reward. One thought that crosses my mind is that the first question should be “why did I have separate databases to start – so would I be happy with just one (container) database now?” (There are all sorts of good answers to that question, of course, but it should still be asked.)

By: Jonathan Lewis

Jonathan Lewis — Thu, 13 Dec 2012 10:50:53 +0000

Stefan,

Good questions. Both political and technical

Apart from the SaaS and Cloud stuff, there’s also the “consolidate everything onto a couple of Database Machines (formerly Exadata)” idea – and given the ever increasing number of background processes (something like 30 when I last checked 11.2.0.3), something needed to be done to massively long queues for CPUs even when the processes were doing virtually nothing when they got to a a CPU.

By: Jonathan Lewis

Jonathan Lewis — Thu, 13 Dec 2012 10:38:59 +0000

“does MS SQL server have AWR equivalent of Oracle?”
Not as far as I know – but they’ve been developing all sorts of monitoring and instrumentation that is going in the same direction. I’m fairly sure I’ve seen 3rd party applications that have then been supplied to sample and capture what’s available. (Remember bstat/estat ?)

One of the big issues of adding any enhancements to anything, anywhere, is the need to avoid breaking other bits that you didn’t realise were related. Some extensions are less likely to cause problems than others, but I wouldn’t particularly pick on the data dictionary as the killer problem.

By: Jonathan Lewis

Jonathan Lewis — Thu, 13 Dec 2012 10:35:43 +0000

“Not as flexible as MSSQL, though: that one can restore/recover and roll-forward each PDB because each set of logs is exclusive. Let’s hope the PDB in 12c whenever it comes out will allow something similar. Otherwise it’s won’t be very useful in true consolidation”

A related observation – that may give you some hope – was a comment (with the usual “safe harbor” slide) that you could upgrade by creating a new container database in the new version of Oracle, then unplug your databases one by one from the old container database and plug them into the new. This, surely, requires some interesting and significant engineering that could include the features necessary to allow differential recovery. (Bear in mind, you can recover a tablespace in situ, already).

By: Jakub Wartak

Jakub Wartak — Tue, 23 Oct 2012 16:11:41 +0000

Jonathan, I think there is additional option (benefit?) for using this “pluggable” databases(s): having a single redo stream provides SCN consistency across N separate database/IT systems. Reality shows (e.g. in deployments of multiple separate but interconnected systems) that having consistent replica for DR across 2+ systems from point datacenterA to datacenterB was almost impossible in real life without high end storage solutions (e.g. EMC consistent groups with SRDF or some other form of snapshot replication). With “PDB” it can be as simple as putting everything into “one” box… I’m just wondering how they are going to handle “PDB” with RMAN and so on? If i would like to intentionally perform TSPITR/Flashback db for just single of the container database, will it be possible at all?

By: Stefan K.

Stefan K. — Sun, 21 Oct 2012 10:43:20 +0000

Hi,
i wondered about a few things as i have heard of that new behavior and as i have seen the presentation:

* How many oracle databases/instances are running as a SaaS, so that the customers (mostly service providers) can get a benefit of it? Is this just to follow up the “Cloud hype”?
* Several “kind of” databases (OLTP and OLAP) were plugged together In the presentation. How should this work with one instance? Usually DW databases got a oppositional configuration (just think about dynamic sampling, etc.).
* How to protect one database from going crazy of the others? Today you can easily implement something like Solaris Resource Manager or other kind of OS features in a consolidated environment. With such a consolidated approach you have to use Oracle Resource Manager (??), which can make things more complex.

I guess there are so many pitfalls :-)) .. let’s see ..

Regards
Stefan

By: Noons

Noons — Thu, 18 Oct 2012 22:22:18 +0000

Thanks for that, Jonathan. If it ends up being like the RAC redo groups, that’s not half bad. In fact, it’s beginning to look like the PDB concept is similar to extending the “single-node RAC” idea.
Not as flexible as MSSQL, though: that one can restore/recover and roll-forward each PDB because each set of logs is exclusive. Let’s hope the PDB in 12c whenever it comes out will allow something similar. Otherwise it’s won’t be very useful in true consolidation.
One area where it could improve on MSSQL for example would be in keeping the access to multiple temp tablespaces. Which Oracle supports now and MSSQL doesn’t. It’s proven to be an invaluable feature in my efforts to consolidate the multiple fractional app dbs I had here into multiple schemas in a single instance: each gets its own temp and I never have to worry about one app causing another to exhaust temp space because some duhveloper decided to code a huge SELECT DISTINCT instead of joining tables!

By: Oracle Database 12c and its features… « musingdba

Oracle Database 12c and its features… « musingdba — Thu, 18 Oct 2012 19:21:20 +0000

[...] [thanks to Jonathan Lewis - Pluggable 12c] [...]

By: laimisnd

laimisnd — Thu, 18 Oct 2012 11:50:51 +0000

interesting… From the glance it looks like implementing one stream of redo is more difficult than keeping them separate (?)

btw: does MS SQL server have AWR equivalent of Oracle? Because if one starts thinkink about fundamental Oracle and MS SQL server differencies then the DD(data dictionary) and all SYSTEM packages come into mind. It’s no problem to have packages like SQL server has in the master database.
But packages operating over DD tables of attached (“plugged inn”) database would automatically be Data Dictionary version specific meaning they can not be upgraded by a simple plug-inn.
Now for the Data Dictionary… Well, some new features like say introducing new type of tables (subpartitioned tables for example) require DD upgrade. Can binaries be designed so that they work both for the new and old dictionary ? Hmmm, everything is possible but that is a legacy which will take it’s toll in development costs and bugs. On the other hand DD changes are not so frequent and complex, actually.