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.
By Mouhamadou Diaw 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…
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…
By Mouhamadou Diaw 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…
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…
This post gives a short intro to directory naming, shows how to import from tnsnames.ora to an LDAP directory. Finally, as an alternative, you get an example how a TNS connection string looks like in ldif file format. LDIF can be used universally to export and importing data to LDAP directories. What is directory naming? In order to connect to…
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…
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…
Another nice feature was just committed for PostgreSQL 15: Add UNIQUE null treatment option (discussion here, commit details here). What is it about? The answer is quite easy if we do a little example which shows the effect of this new feature. Consider the following table and unique index: postgres=# create table t ( a int ); CREATE TABLE postgres=#…
The aim of that blog is to look into Oracle REST Data Services (ORDS) DB connection with TNS. This is following some experience at a customer who wanted to move to latest version of ORDS with APEX 21.2, in late 2021, and run into an issue. For general presentation about ORDS installation please see the blog of my colleague Lazhar…
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…
As development of PostgreSQL 15 is on its way, more and more features get committed. Today we’ll look at a new feature which is not a hammer feature, but a nice thing to have and to know about. If you take a look at how many settings PostgreSQL comes with as of today, there are 353 (This is PostgreSQL 15dev):…
For a customer, I had to check if partitioning improves performance of massive and concurrent inserts. The goal is to execute several Inserts in parallel via dbms_parallel_execute package (my previous blog “parallelize your Oracle Insert with DBMS_PARALLEL_EXECUTE” explains how to use dbms_parallel_execute). The idea is to insert more than 20 millions of rows in 2 tables : One table not…
