Category: Oracle

Oracle Linux in-place upgrade. Good, bad and the cloud. #JoelKallmanDay

Oracle Linux 7 was released in 2014 and the system is close to its sunset. The premier support for the system will be wrapped up by July 2024 and it is time to think about moving forward. All the new systems, as I can see, are using version 8 and some even version 9. So it is time for an upgrade. And when we speak about upgrading we usually have two options – in-place and out-of-place. The in-place upgrade modifies the system on the same box keeping all the users data intact and the second approach is more like a migration when you move all your app stack and data to a new box with a new version of the OS. So, how difficult is the in-place upgrade and when it makes sense?

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Sample Go application with database backend

Yes, this is one more sample app as there are probably thousands already on the internet. We have tons of sample apps from different vendors with various types of licenses available on different repositories. Nevertheless sometimes I struggle to find exactly what I need – a simple app with a database backend which can work with Oracle Autonomous databases and optionally with Postgres backend. In my everyday life I primarily use Go as a programming language and I would like to have such an app written using that language. So, eventually I gave up and created my own application with a simple frontend and two (as for now) options for backend databases – Oracle and Postgres.

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Oracle Apex on ATP with custom domain

If you have an Apex app on top of your Oracle Autonomous database you have the application URL like https://m5c5hpup7eqqydh-glebatp01.adb.us-ashburn-1.oraclecloudapps.com/ords/r/covid/covid-ontario/covid_ontario. This is already better than it used to be before and have a friendly path in the URL but what if you want to use your own domain address and custom URL? This blog is about how to set it up using reverse proxy. The way with a custom ORDS is a subject for another post.

So, you have your own domain registered in DNS, for example apex.gleb.ca and an application like I’ve listed above. What you want to do is to make the application URL as https://www.apex.gleb.ca/covid/ . What we are going to use is a virtual machine with a Nginx web server serving as a reverse proxy to your Apex application created on the Oracle Autonomous database.

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Oracle Database Service for Azure

Recently Oracle and Microsoft announced availability of their new service – Oracle Database Service for Azure. It raises the level of integration and interoperability between Oracle Cloud and Microsoft Azure. With the new service Microsoft’s customers are able to create and manage Oracle databases created in Oracle cloud and use them for applications located in Azure. That sounds great and moves us one step closer to a real multi-cloud environment. Before proceeding, let me clarify what I mean as the “real” multi-cloud. I mean an environment where different pieces of the same IT service are located in different clouds working as a whole.

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MongoDB on Oracle Autonomous

Earlier this year Oracle announced support for MongoDB API on the Oracle Autonomous database family. It has been recognized as a huge milestone by Forbes and multiple other analysts, technical and market experts. In my opinion it was logical and fully predicted one more step to the main idea of “Converged Database”. I didn’t coin that term – Oracle was using it for two or three years as of now. The main idea is to create a fully managed database platform supporting the most of APIs and interfaces and put the data together under the Oracle Autonomous Database umbrella. Here I will try to look inside and understand what it is, how it works, what is supported and what is not.

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Data Pump Export on Oracle Autonomous

The blog was supposed to be a small how-to but it has grown to a bigger one and hopefully might help to avoid some minor problems while exporting data from an Autonomous Database (ADB) in Oracle Cloud (OCI). It is about exporting data to the Oracle DataPump format to move data to another database or as a logical “backup”.

Oracle documentation provides sufficient information but I find it more and more difficult to navigate considering the number of options and flavours for Oracle databases. There are some new ways and tools around Oracle OCI ATP which can help in some cases. If you want you can jump directly to the end to read the summary.

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Blog on Oracle OCI ARM free tier.

This blog was primarily driven by questions from my peers and colleagues who wondered where my blog was hosted and how it was created. It might help to move from a hosting platform to your own website and where to start.

Like most bloggers I started my blog using one of the hosting platforms but soon after found some limitations in choosing appearance, plugins and was a bit annoyed by some commercial banners on my page. After a while I decided to move to my own site. I bought a domain name for myself and created my own environment using the WordPress software on a cloud VM. It didn’t cost me too much but it was not entirely for free. When Oracle introduced some additions to the always free set of resources. I decided to give it a try and move my blog entirely to the OCI free tier.

For those who would like to skip the reading and try, I have a set of Terraform scripts on GitHub. They haven’t been updated lately and use not the latest versions but can be a good place to start.

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Terraform modules simplified.

Terraform is probably already the de-facto standard for cloud deployment. I use it on a daily basis deploying and destroying my tests and demo setups in my Oracle cloud tenancy. Sometimes the deployment environment for a demo has too many files or some files inside are really big and hard to read due to the number of different resources and parameters included there. How can we make our configuration more usable? Let’s try Terraform modules and demonstrate how they work.
For our tests we are going to use terraform v1.0.3 and Oracle Cloud Infrastructure (OCI). You will need a working OCI and on your machine with terraform defined environment variables. The full list of required environment variables will be provided in the README file in the GitHub repository.
Let’s say we have a simple demo or test configuration with a dedicated network, internet gateway and a VM. And we want to assign multiple security rules using security lists and maybe one or two security groups. We can include all those rules to the configuration file for the network but maybe there is a better way. What if we want to reuse the similar set of the security rules and security groups not only to that deployment but share with some other stacks? We can try to use Terraform modules.

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Exadata Cloud at Customer – free space in ASM and adding a new database.

Some time ago I wrote a short blog about dependencies between the number of enabled CPUs and how many databases you could build. Today we got another error when we were trying to create a new database. Here is the screenshot of the error.

If you can’t read it on a small screen it says “Create Database operation failed due to an unknown error. Refer to work request ID 2580d3ff-064e-4e6f-ab06-1327fd02f40e when opening a Service Request at My Oracle Support.” and provide an error code which is “Error“

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Linux Hugepages and AUTO_ONLY in Oracle 19c.

Most Oracle DBA are sufficiently educated about benefits using large memory pages for Oracle database SGA to reduce overhead and improve performance. If you want to read more about it you can start from that Oracle blog or read it from other multiple articles and blogs. Oracle is using parameter use_large_pages to direct behaviour of an Oracle instance during startup.

In the previous versions before 19c we had three possible values – “TRUE”, “FALSE and “ONLY”. Since Oracle 11.2.0.3 the “TRUE” meant that the instance will allocate as many hugepages as free available in the system and get the rest from the normal small pages. The “FALSE” would tell it to not use the hugepages at all and the “ONLY” would be able to start an instance only if sufficient number of free hugepages is available in the system to fit all SGA in it. The “TRUE” was default for all databases. 

In the 19c version we got one more value – “AUTO_ONLY” and now it is the default value for Exadata systems running Oracle Database 19c. The description in documentation is not totally clear and sounds very similar to the description of “ONLY” value. Here is an excerpt from the documentation:

“It specifies that, during startup, the instance will calculate and request the number of large pages it requires. If the operating system can fulfill this request, then the instance will start successfully. If the operating system cannot fulfill this request, then the instance will fail to start.”

Let me show you how it works. Here is my sandbox with a 19c database and no hugepages is configured on the box by default. 

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