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Mouhamadou Diaw

Managing Refreshable Clone Pluggable Databases with Oracle 21c

By | Database Administration & Monitoring, Database management, Oracle | No Comments

A refreshable clone PDB is a way to refresh a single PDB instead of refreshing all PDBs in a container as in a Data Guard environment. It consists to make a clone of a source PDB and the clone PDB is updated with redo accumulated since the last redo log apply In this blog I did some tests of this feature Refreshable pluggable databases. I am doing my test with Oracle 21c but this feature…

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Stéphane Haby

SQL Server: Last duration for all SQL Server jobs in TIME format from HHmmss to HH:mm:ss

By | Database Administration & Monitoring, Database management | No Comments

For a customer, I want to see all last duration for a job and have a good format for it. The query to do it is very simple (at the beginning…) but when I try to have a better view it was more complicated. Let me try to explain you. As you now, to have the history of all jobs on SQL Server, we use system views dbo.sysjobhistory and dbo.sysjobs I use this query to…

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Mouhamadou Diaw

Character Sets and Oracle 21c PDBs : How It Works

By | Database Administration & Monitoring, Database management, Oracle | No Comments

When creating a database in a multitenant environment we must understand how character set works for CDB and PDBS. In Oracle documentation we can find following lines -When the character set of the CDB root is AL32UTF8, PDBs that are plugged into the CDB can have a different character set from the CDB root. PDBs that you create from PDB$SEED inherit the AL32UTF8 character set from it, but you can migrate the PDB to a…

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Marc Wagner

Creating KVM Database System on separate VLAN network on ODA

By | Oracle | No Comments

Oracle appliance is proposing various possibilities for creating databases either on the Bare Metal or using KVM DB System. Each DB System will host a single database in a separate VM. What about having each DB system running a separate network? In this blog I would like to share my tests and findings about how to create additional network on the ODA and how to create DB System on separate VLAN interface. The principle would…

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Alain Fuhrer

How to configure Linux Server to run Oracle Database 19c on Persistent Memory

By | Database Administration & Monitoring, Oracle | No Comments

Introduction to Persistent Memory In the last few years, storage media have become more and more advanced and faster. Today, SSD disks are almost standard as storage and if an Oracle database really has an I/O critical workload, nvme storage is often used. The latest evolution in database storage is persistent memory which improves latency and I/O throughput compared to nvme. Oracle has also recognized the advantage of PMEM, and it is also used in…

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Joan Frey

How to install a specific version of MariaDB

By | Database Administration & Monitoring | No Comments

Recently, we had to upgrade a MariaDB server from version 10.5.4 to 10.5.13. Before to do the upgrade on a production server, I wanted to test it on a personal VM. But first, I had to find how to install the specific version 10.5.4 of MariaDB. Today, I’m going to explain how to install a specific version of MariaDB and how to upgrade it to an other specific version.

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Olivier Spiesser

What is Variable Precedence in Ansible?

By | Ansible | No Comments

In Ansible, definition of variable precedence is often overlooked. Despite what I wrote in my previous blog (Use Ansible like a Programming Language), Ansible is not exactly a programming language. There is a difference, especially on the way variables are managed. At the beginning, as I am used to scripting, I was a bit confused by the way Ansible is handling variables. For example, let’s say you have a string variable defined in group_vars/all.yml: —…

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Karsten Lenz

Updating Password in PostgreSQL from md5 to scram-sha-256

By | Database Administration & Monitoring, Postgres | No Comments

Many installations have a history of many major PostgreSQL releases. With PostgreSQL 10 comes scram-sha-256 for hashing passwords, by installing from packages scram-sha-256 is the default setting for new installations since PostgreSQL 13. With this small blog I will describe how to update password from md5 to scram-sha-256. For the installation of PostgreSQL there are many blogs at dbi or articles from dbi. Blog at dbi-services.com Article at heise.de So I will not repeat this…

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