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May 2018

FBIs don’t exist

This is a reprint (of a reprint) of a note I wrote more than 11 years ago on my old website. I’ve decided to republish it on the blog simply because one day I’ll probably decide to stop paying for the website given how old all the material is and this article makes an important point about the need (at least some of the time) for accuracy in the words you use to describe things.


There’s no such thing as a function-based index.

Well, okay, that’s what the manuals call them but it would be so much better if they were called “indexes with virtual columns” – because that’s what they are and that’s a name that would eliminate confusion.

Broadening Your Audience

I spent this week speaking at two conferences that may not be familiar to my usual crowd:
Techwell StarEast Testing Conference in Orlando, FL
Interop ITX Data Conference in Las Vegas, NV

ADWC – the hidden gem: Zepplin Notebook

In the previous blog posts I explained how to create, and stop/start the Autonomous Data Warehouse Cloud service. And I didn’t show yet how to connect to it. It is easy, from sqlplus or SQL Developer, or SQLcl.

But there’s something more exciting to run some SQL queries: the Oracle Machine Learning Notebooks based on Apache Zepplin. At first, I didn’t realize why the administration menu entry to create users in the ADWC service was named ‘Manage Oracle ML Users’, and didn’t realize that the ‘Autonomous Data Warehouse Cloud’ header was replaced by ‘Machine Learning’.

Free Conference (*) in May!

How do you fancy going to a full-day, five stream conference, for free? With a great agenda including Pete Finnigan talking on the hot topic of GDPR; Chris Saxon, Nigel Bayliss and Grant Ronald giving us the latest low-down on optimizer, 18C database features for developers and AI powered apps? Stalwarts of the Oracle community like Robin Moffat, Zahid Anwar and Andrew Clarke giving their real-world view?

FBI Limitation

A recent question on the ODC (OTN) database forum prompted me to point out that the optimizer doesn’t consider function-based indexes on remote tables in distributed joins. I then spent 20 minutes trying to find the blog note where I had demonstrated this effect, or an entry in the manuals reporting the limitation – but I couldn’t find anything, so I’ve written a quick demo which I’ve run on to show the effect. First, the SQL to create a couple of tables and a couple of indexes:

StarEast, InteropITX and GDPR

I’m getting ready to get on a plane between two events today and have been so busy, that there’s been a break in blogging.  That’s right folks, Kellyn has let a few things slide….

ADWC – a Docker container to start/stop Oracle Cloud services

In the previous post, I’ve explained how to start and stop the Autonomous Data Warehouse Cloud service from PSM (PaaS Service Manager). There’s a setup phase, and a run phase starting with service-start and ending with service-stop. And the setup is specific to an Oracle Cloud account, storing information in the local user home. You may want to run different setups, and even provide an easy way to start/stop an Oracle Cloud service without knowing the user, password and tenant name.

A Docker container is perfect to isolate this.

ODTUG Kscope18 Conference: Change of Presentation Times

For those of you that were planning to attend my presentations at the upcoming ODTUG Kscope18 Conference in Orlando (yes, I’m specifically talking to the two of you), both presentations have been allotted new times and locations. They are now confirmed as: New Indexing Features Introduced in Oracle 12c Release 2 (and 18c): When:  June […]

18c Scalable Sequences Part II (Watch That Man)

In Scalable Sequences Part I, I introduced this new 18c feature (although it was hidden and undocumented in previous releases). By adding a 6 digit prefix value that constitutes the first 3 digits for the Instance Id and the next 3 digits for the Session Id, it results in a sequence value that doesn’t always […]

ADWC: start/stop with PSM Command Line Interface

In the previous post, I explained how to create an Autonomous Data Warehouse with PSM (PaaS Service Manager Command Line Interface). The most common operation you want to do with it is starting and stopping the service. This is the best way to save credits for hourly billed services. And PSM is the easiest: run from everywhere (it is Python 3) and no need to provide credentials each time. In the previous post, I explained how to setup PSM for the ADWC service.

Unfortunately, for starting and stopping the instance you may realize that: