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VirtualBox 6.1.12

The VirtualBox 6.1.12 maintenance release has appeared with all the Oracle quarterly patches.

The downloads and changelog are in the usual places.

I’ve installed it on Windows 10, macOS Catalina and Oracle Linux 7 hosts with no dramas. My Vagrant builds seem happy too…

Cheers

Tim…

Fetch First vs. Rownum

I’ve pointed out fairly frequently that if you’re running Standard Edition but would like to take advantage of a few features of the Partitioning option then you might be able to do something appropriate with Partition Views (but I’ve just discovered while searching my blog for a suitable item to link to that I haven’t published any of my PV notes on the blog).

I’ve also pointed out that while 12c allows you to use “fetch first N rows” instead of “where rownum <= N” there’s a hidden threat to using the feature because “fetch first N” turns into a hidden row_number() over() analytic function.

DBPod – le podcast Bases de Données

By Franck Pachot

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J’essaie quelque chose de nouveau. Je publie beaucoup en anglais (blog, articles, présentations) mais cette fois quelque chose de 100% francophone. En sortant du confinement, on reprend les transports (train, voiture,…) et c’est l’occasion de se détendre en musique mais aussi de s’informer avec des podcasts. J’ai l’impression que c’est un format qui a de l’avenir: moins contraignant que regarder une video ou ou lire un article ou une newsletter. Alors je teste une plateforme 100% gratuite: Anchor (c’est un peu le ‘Medium’ du Podcast).

19c: scalable Top-N queries without further hints to the query planner

By Franck Pachot

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The FETCH FIRST … ROWS ONLY syntax arrived in Oracle 12c and is much more convenient than using a subquery with ‘ORDER BY’ wrapped in a “WHERE ROWNUM < …” around it. But as I mentioned in a previous post it required the FIRST_ROWS() hint to get correct estimations. In SQL you don’t want to overload your code for performance, right? The RDBMS optimizer does the job for you. This was a bug with this new FETCH FIRST syntax, that is fixed (See Nigel Bayliss post about this) in 19c:

Vagrant and Docker Builds : ORDS 20.2 and SQLcl 20.2 Updates

https://oracle-base.com/blog/wp-content/uploads/2019/12/ords-2-258x300.png 258w" sizes="(max-width: 191px) 85vw, 191px" />

The recent Oracle REST Data Services (ORDS) 20.2 release prompted my usual reaction. I’ve gone through my Vagrant and Docker builds, and updated them to use ORDS 20.2 and SQLcl 20.2.

The Vagrant database builds, which include ORDS, can be found here.

The Docker ORDS builds can be found here.

Min/Max costing

A question about the min/max index scan appeared on the Oracle Developer Community forum recently. The query supplied in the thread was a little odd – you might ask why anyone would run it as it stands – and I’ve modified it to make it even stranger to demonstrate a range of details.

I’ll start with a simple data set, not bothering to collect stats because that will be done automatically on create for my versions:

Linux Containers (LXD) and Oracle 18cXE – installation

There’s a lot of articles about installing Oracle XE 18c on Docker. But Docker is not the only containerization technology on the market.

In this article, we are going to create Oracle XE 18c installation in Linux Containers (LXD)

A bit of history – LXC vs LXD

When we start our adventure with Linux Containers we might get confused by 2 different naming conventions – LXC and LXD. To clarify let’s talk about some history.

In the year 2000 FreeBSD developers introduced the jail command, which was used to isolate an application process from the main operating system space, but it was not very intuitive and functional.

Video : Resource Manager : Runaway Query Management

In today’s video we give a quick demonstration of using Resource Manager to cancel a long running SQL statement.

This video is based on a series of articles from Oracle 8i to the present day. There is an example here.

Although there are aspects of it throughout most of the Resource Manager articles on the website.

Two Years at Microsoft

This is commonly the time at any company I discuss how I’m about to move on…

Nope, not planning on going anywhere… I know, it’s odd for everyone involved, but we’ll all get used to it.

Massive Deletes

One of the recurrent questions on the Oracle Developer Commuity forum is:

What’s the best way to delete millions of rows from a table?

There are an enormous number of relevant details that you need to know before you can give the “right” answer to this question, e.g.