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Database

Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.

OCI : How to change VCN Name?

Starting my first experience with Oracle Cloud Infrastructure, I played with my lab and wanted to change my VCN name. I thought it might be more than easily with the Web Console, but could realise this was not possible. I find out that the only way to do it was through the command line. So great opportunity to start learning… 

SEHA on ODA?

SEHA means Standard Edition High Availability. SEHA is fully integrated with Oracle Grid Infrastructure starting with Oracle Grid Infrastructure 19c, and more specifically since RU 19.7. SEHA provides then cluster-based failover for single-instance Standard Edition Oracle Databases using Oracle Clustware. It is important to mention that Oracle removed Oracle RAC from SE2 Edition since 19c. Most important things to know… 

Upgrade OEM 13c from R4 to R5

By Mouhamadou Diaw Upgrading Enterprise Manger Cloud Control can be tricky. In this blog I am describing an upgrade I did for a client. The source version is OEM13c R4 And the target version will be EM13c R5 Before starting I did following tasks -Copy the key in the repository -set the parameter “_allow_insert_with_update_check” to true You can now stop… 

How to submit a talk for a conference

I already did some talks at conferences and I had already the honor to select talks for a conference. During this talk selection I found some excellent examples on how to do to a proposal, but unfortunately also some examples that could be improved. Also my own learnings from proposals will run into this post, because I know, it’s not… 

Configuring a SMTP relay on Oracle Linux Server v8

For some internal DMK (https://www.dbi-services.com/fr/produits/dmk-management-kit/) development I had to configure a SMTP relay on my VM. Purpose of the SMTP relay is to send the email locally from DMK without any authentication. This Email will be transferred to the SMTP server created by one of my colleague on our AWS Cloud. This SMTP server is of course using authentication. To… 

SQL Server: Heap page deallocation and IndexOptimize

Introduction HEAP tables are a type of data structure that, unlike a clustered index table, does not have a specific ordering of its rows, making them faster to insert and delete data. They are often used for temporary “staging” tables. This is all fine. But, if your table is never dropped and reused over time for data loading, you need… 

PostgreSQL 16: reserved_connections

The maximum number of connections that PostgreSQL will allow, is controlled by the max_connections parameter. By default this allows a maximum of one hundred connections: In reality not one hundred connections are allowed for normal users, because some of those connections are reserved for superusers. This is controlled by the superuser_reserved_connections parameter which, by default, is limited to three: This… 

Converting from Unix timestamps to “real” timestamps in PostgreSQL

Recently we’ve been asked how an application can be changed from using Unix timestamps to PostgreSQL timestamps. It is still not so uncommon to store dates and times in numeric data types, but if you want to work with timestamps you should use the timestamp (with timezone) data type, and not abuse other data types for that. Lets do a… 

Patching ODA HA from 19.10 to 19.17

By Mouhamadou Diaw In this blog I am describing an ODA HA (serveroda1 and serveroda2) patch from 19.10 to 19.17. The process is the same that patching a non-HA ODA. Few tasks may need to be done on both servers, otherwise all steps are done from one node. If there are some tasks needed on both nodes, we will specify.…