Top 60 Oracle Blogs

Recent comments


18.2 patch… painless for me

18.2 was released a few days ago, so I thought I’d throw it against my 18c instance and see how things played out.  This was just a single instance database, running with a single pluggable.

When you screw up … make it positive for your users

Yesterday I was caught up in an interesting SNAFU at my local Supermarket.  All of the checkout registers shut down, thus making it impossible to pay for groceries.  Later on Twitter, the company apologized as we discovered it was actually a nationwide outage!


Concurrency … the path to success and the path the failure

Let’s face it. Concurrency is a good thing when it comes to database applications.

Data Hashing

Here’s a little-known feature that has been around since at least Oracle 10, though I don’t think I had ever seen it in the wild until today when someone reported on the ODC (OTN) database forum that they had a problem getting repeatable results.  It’s always possible, of course, that failure to get repeatable results is the natural consequence of running queries against a multi-user system, but if we assume that this was not the cause in this case we have to ask why a special hashing function that Oracle supplies to allow you to check that a set of data hasn’t changed gives you different results when “the data hasn’t changed”.


Some members of the Oracle community got well and truly into the April Fools Day spirit this year.

There were plenty of very earnest looking blog posts about a new 18c function – “TO_DOG_YEAR”.  You can read their posts here

New day….new month….New AskTOM

It’s a big day here at AskTOM HQ !

Hybrid histograms

Just a quick post here so I could consolidate some information about histograms in 12c.

Trip down memory lane

I did a little video for St Patricks day, but it also brought back memories of my first computer experiences.  A Sinclair ZX80, a Commodore 64, and many other machines that I thought were so cool for their time.

Feel free to share your experiences in comments.

Text indexes for numbers

We had an AskTOM question recently about being able to search for numbers within a concatenated list. The particular issue was a list of mobile phone numbers, but this is really just about tackling the larger issue of finding numbers within list.

Let’s create a simple example to see where things can break down (and how we can fix them).

Deferred Invalidation

I was going to write an article on the way 12.2 has introduced the option for “deferred invalidation” for a number of DDL operations, but I did a quick google search before I started writing and found that both Franck Pachot and Richard Foote (yes, rebuild index is one of the operations) had got there long ago, so here are a couple of links – as much for my own benefit as anything else:

Richard Foote:

Franck Pachot: