Database Administration & Monitoring

Magic Upgrade to 21c with Replay Upgrade Feature

Last week I did some upgrade tests from 19c to 21c. The plan was to copy a 19c PDB to a CDB 21c using Online Clone and then upgrade it to 21c. I have done this many times for 19c(…)

In which order do triggers fire in PostgreSQL?

When you are working with triggers it might be important to know in which order they fire. Of course, a "before" triggers fires before an "after" trigger. But what happens if you have two or more triggers for the same(…)

How much shared memory is PostgreSQL using? (2) – details

In the last post in this two post series we've briefly looked at configuring huge pages on Linux for PostgreSQL. It became clear, that calculating the number of huge pages purely based on the setting of(…)

How much shared memory is PostgreSQL using? (1) – basics

Have you ever wondered if the value of shared_buffers is the only setting which controls how much shared memory PostgreSQL is actually using? There was a nice addition committed to PostgreSQL 15 recently, which helps in answering(…)

After startup database with srvctl, sqlplus as sysdba results in ORA-12547: TNS:lost contact

A few days ago a customer called me, that he have a strange issue with a new created database in a oracle restart configuration with 19c. Problem The customer has patches his 19c Databases with the newest RU and(…)

MongoDB Monitoring using Nagios

The question comes frequently: How can I monitor my MongoDB cluster (ReplicaSet or Sharded) in a production environment? To answer this question we need first to get an overview of all potential monitoring solutions, and then compare them one by(…)

Temporal tables for PostgreSQL 15?

One of the features which is currently missing in PostgreSQL is Temporal Tables. Other database systems have that since a long time and many people want to have in PostgreSQL as well. If you don't know what it is,(…)

Parallel distinct for PostgreSQL 15

When parallel execution was introduced with PostgreSQL 9.6 it was quite limited and supported only a few operations to run in parallel. Over time more and more operations were enabled to run in parallel. When PostgreSQL 15(…)

What are those *_init files for in PostgreSQL?

Quite some time ago I've written about relation files in PostgreSQL and when they get created. In that post we talked about the files containing the actual data, the free space map (fsm) and the visibility map(…)

How to find the TLS used for the SQL Server connection

For a customer, I do some research to find which TLS is used on the SQL Server environment. The only way is to create an Extended Event. A big limitation is that the event used is only available on SQL(…)