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A mostly academic post about startup triggers and when they fire in Real Application Clusters

Out of curiosity I wanted to figure out when and how often startup triggers fire in RAC 19c. Do they fire when all instances of the database are up (e.g. only once), or do they fire for once each instance? A little experiment reveals the behaviour. As the title reads this is mostly academic, I hope it’ll save me 5 minutes some time in the future. Maybe it saves you 5 minutes right now?

I am using Oracle 19.8.0 RAC in a two node configuration, with the database created as a container database (CDB). To figure out what happens with the startup trigger I created a little bit of infrastructure, like so:

Video : Vagrant Oracle Real Application Clusters (RAC) Build

In today’s video we’ll discuss how to build a 2-node RAC setup using Vagrant.

This video is based on the OL8 19c RAC build, but it’s similar to that of the OL7 19c RAC build also. If you don’t have access to the patches from MOS, stick with the OL7 build, as it will work with the 19.3 base release. The GitHub repos are listed here.

If you need some more words to read, you can find descriptions of the builds here, as well as a beginners guide to Vagrant.

Direct Path

Here’s a note that I might have written once already – but I can’t find it and I’ve just been reminded about what it (might have) said by a posting that came up on the Oracle database forum in the last few days.

The posting in question is asking why, after setting the hidden parameter _serial_direct_read to ‘always’ a particular query is now taking hours to complete when it used to complete in a minute or so.

Oracle MAA reference architecture and HA, DR, RTO, RPO

By Franck Pachot

I may have mentioned in some previous blog post that, in my opinion, the names of Oracle Database features make sense on the vendor product management context more than in a user context. I’m not saying that it is good or bad. There are so many features, that can be combined, and that evolved for many years. The possible use cases is unlimited. What I see customers doing in Europe is very different from what I have seen in US companies or in Africa for example. What I’m saying is that most of the time you need a vendor-to-user dictionary when reading Oracle documentation and presentations. I’ll focus here on the MAA reference architecture. Yes, acronyms add to the complexity. MAA means Maximum Availability Architecture. Because when you have High Availability features for decades, you need another name when you bring an “higher” High Availability.

JDBC & the Oracle Database: if you want Transparent Application Failover you need the OCI driver

This is the second article in the series of JDBC articles I’m about to publish. It covers an old technology that’s surprisingly often found in use: Transparent Application Failover (TAF). It’s a client side feature for clustered Oracle databases allowing sessions (and to some extent, select statements) to fail over to a healthy node from a crashed instance.

I would wager a bet that you probably don’t want to use Transparent Application Failover in (new) Java code. There are many better ways to write code these days. More posts to follow with my suggestions ;)

Well, then, why bother writing this post? Simple! There is a common misconception about the requirement: since Transparent Application Failover relies on the Oracle client libraries, you cannot use it with the thin driver. The little tool I have written demonstrates exactly that. And besides, I had the code more or less ready, so why not publish it?

Oracle Database 19c RAC On OL8 Using Vagrant

On Sunday 17th May I started the process of putting together a Vagrant build of Oracle 19c RAC on Oracle Linux 8 (OL8.2 + EUK). I figured it would take me about 20 minutes to amend my existing OL7 build, but it took the whole of that Sunday, every evening for the following week, and the whole of the following Saturday and Sunday to complete it. There were some late nights, so from an hours perspective it well over 5 days of work. Most of that time would have been completely unnecessary if I wasn’t an idiot.

First things first. The result of that effort was this build on GitHub, with an associated article on my website describing the build in more detail.

Data Guard and RAC on Docker : Perhaps I was wrong?

I’ve talked a lot about Docker and containers over the last few years. With respect to the Oracle database on Docker, I’ve given my opinions in this article.

Over the weekend Sean Scott tweeted the following.

“A while back @oraclebase said Data Guard didn’t make sense on Docker.

RAC on Azure- Link to Microsoft Tech Blog

Some folks stated they were having trouble finding this, so I’m posting a link here for the blog I wrote on the Microsoft Tech Community Blog on my opinion about building out RAC on Azure.


Creating a RAC 12.1 Data Guard Physical Standby environment (3b)

Huh, what is this I hear you ask? Part 3b? Oracle 12.1? Well, there’s a bit of a story to this post. Back in December 2016 I started to write a series of blog posts (part 1 | part 2 | part 3 | part 4) about how I created a standby database on RAC 12.1. For some reason I forgot to post this part. Up until now the step where I am creating the broker configuration was missing. Thanks to a friend I discovered my mistake.

That demned elusive PQ slave

With apologies to Emma Orczy for stealing a line from “The Scarlet Pimpernel” … </p />

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