Oracle

Franck Pachot's picture

ODA Lite: What is this ‘odacli’ repository?

When ODA Lite was introduced, with ODA X6-2 S/M/L, and now with ODA x7-2 S/M, a new ‘odacli’ was there to manage it. It will probably replace the oakcli for ODA HA as well in the future. One big difference: it uses a repository to record the configuration and the operations. I don’t really like it because when something fails you are blocked. Oracle Support can modify the directory, but they ask for an access to the machine for that and this is not easy in secured environments. Anyway, I really don’t understand why another repository has been introduced. We already have the Oracle Inventory, the Grid Infrastructure resources, the Linux /etc files,… And now we have a closed repository which controls everything, accessible only with the very limited odacli commands which are not the best example of automation code and error handling.

dbakevlar's picture

Scene and Cut. Training Days 2018

I’m recovering after a very successful RMOUG Training Days 2018 and now looking towards the next year.  The board elections come up in two months and I’m happy to say, that the goals that I hoped to achieve in my year as president, the board was able to achieve even as I worked on the conference and started as the president for the SQL Server User Group here in Denver, all in parallel.

dbakevlar's picture

RMOUG Training Days 2018, Day 2

So I survived the first day of RMOUG Training Day’s workshops, sessions and the VIP Reception ran a little later last night than we originally planned.  I had to present in the first session of the day at 8:30am, so I was a little worse for wear when I checked into my room for DevOps for the DBA.

I really appreciate all the attendees that came to the session, the great questions and feedback I received.  Its not easy to pay attention to a speaker that early in the morning!

kevinclosson's picture

A Word About Amazon EBS Volumes Presented As NVMe Devices On C5/M5 Instance Types.

If It Looks Like NVMe And Tastes Like NVMe, Well…

As users of the new Amazon EC2 C5 and M5 instance types are noticing, Amazon EBS volumes attached to C5 and M5 instances are exposed as NVMe devices. Please note that the link I just referred to spells this arrangement out as the devices being “exposed” as NVMe devices. Sometimes folks get confused over the complexities of protocol, plumbing and medium as I tend to put it. Storage implementation decisions vary greatly. On one end of the spectrum there are end-to-end NVMe solutions. On the other end of the spectrum there are too many variables to count. One can easily find themselves using a system where there interface for a device is, say, NVMe but the plumbing is, for example, ethernet.

Jonathan Lewis's picture

Interval Partition Problem

Assume you’ve got a huge temporary tablespace, there’s plenty of space in your favourite tablespace, you’ve got a very boring, simple table you want to copy and partition, and no-one and nothing is using the system. Would you really expect a (fairly) ordinary “create table t2 as select * from t1” to end with an Oracle error “ORA-1652: unable to extend temp segment by 128 in tablespace TEMP” . That’s the temporary tablespace that’s out of space, not the target tablespace for the copy.

Here’s a sample data set (tested on 11.2.0.4 and 12.1.0.2) to demonstrate the surprise – you’ll need about 900MB of space by the time the entire model has run to completion:

fritshoogland's picture

A look into into Oracle redo, part 4: the log writer null write

This is the fourth blogpost on a series of blogposts about how the Oracle database handles redo. The previous blogpost talked about the work cycle of the log writer: https://fritshoogland.wordpress.com/2018/02/12/a-look-into-oracle-redo-part-3-the-log-writer-work-cycle-overview/. This posts is looking into the execution of the kcrfw_redo_write_driver function executed in the ksbcti.

Jonathan Lewis's picture

Taking Notes – 2

[Originally written August 2015, but not previously published]

If I’m taking notes in a presentation that you’re giving there are essentially four possible reasons:

  • You’ve said something interesting that I didn’t know and I’m going to check it and think about the consequences
  • You’ve said something that I knew but you’ve said it in a way that made me think of some possible consequences that I need to check
  • You’ve said something that I think is wrong or out of date and I need to check it
  • You’ve said something that has given me a brilliant idea for solving a problem I’ve had to work around in the past and I need to work out the details

Any which way, if I’m taking notes it means I’ve probably just added a few more hours of work to my todo list.

Footnote

“Checking” can include:

Jonathan Lewis's picture

Philosophy

Here’s a note I’ve just re-discovered – at the time I was probably planning to extend it into a longer article but I’ve decided to publish the condensed form straight away.

In a question to the Oak Table a couple of years ago (May 2015) Cary Millsap asked the following:

If you had an opportunity to tell a wide audience of system owners, users, managers, project leaders, system architects, DBAs, and developers “The most important things you should know about Oracle” what would you tell them?

I imagine that since then Cary has probably discussed the pros and cons of some of the resulting thoughts in one of his excellent presentations on how to do the right things, but this was my quick response:

If I had to address them all at once it would be time to go more philosophical than technical.

Jonathan Lewis's picture

Assumptions

As the years roll on I’ve found it harder and harder to supply quick answers to “simple” questions on the Oracle-L list server and OTN/ODC forum because things are constantly changing and an answer that may have been right the last time I checked could now be wrong. A simple example of the consequences of change showed up recently on the OTN/ODC forum where one reply to a question started:

Just why do you need distinct in a subquery??? That’s the first thing that appears really shocking to me. If it’s a simple in (select …) adding a distinct to the subquery would just impose a sort unique(as you can see in the explain plan), which may be quite costly.

Franck Pachot's picture

18c Read Only Oracle Home

Capture18c000This is the big new feature of Oracle 18c about database software installation. Something that was needed for decades for the ease of software deployment. Piet de Visser raised this to Oracle a long time ago, and we were talking about that recently when discussing this new excitement to deploy software in Docker containers. Docker containers are by definition immutable images. You need a Read Only Oracle Home, all the immutable files (configuration, logs, database) being in an external volume. Then, to upgrade the software, you just open this volume with an image of the new database version.

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