Ian's Notes

This post assumes that: The target host is running Ubuntu 26.04 The source host is running MacOS with Homebrew installed Preparing the target host Find the interface (usually ethernet) you want to wake on.

I am a Senior PostgreSQL Engineer at Adyen.

If you’re switching disks while the machine is running, the LVM bits might not be detected when the disk is added.

If you see both of these errors, make sure that your /etc/hosts file contains a line for your domain name, pointing towards localhost, for example: 127.0.1.1 ivdl.co.za

This script does the following: Provides a Swiftbar plugin with connect/disconnect options 1Password integration to fetch the VPN password AppleScript popup to request the one time pin Set up passwordless sudo: Edit the sudoers file: sudo visudo Change `…

Introduction Generally, DQL works with entities and time series metrics.

The regex in this post, explained via Regex101 Some applications can log multiple lines per log entry.

If you see a message like the following when running dnf update: Problem: package gcc-8.5.0-24.el8_10.x86_64 from @System requires libgomp = 8.5.0-24.el8_10, but none of the providers can be installed - cannot install both libgomp-8.5.0-26.el8_10.i686 f…

Source In my case there were three matters preventing the drive from being detected: The BIOS version was too old The socket was not set to be recognised as a PCIe device (this requires a beta BIOS version) The drive was seated in the M2_1 socket instead…

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Photo by Kvistholt Photography on Unsplash It is common to run some commands via the postgres account as it is the de facto PostgreSQL super user.

Instead of copying (i.e. via scp or rsync), you can sudo cat the remote file, and pipe it (since pipes cross the SSH boundary) to a local file: ssh <remote host> sudo cat <remote path> > <local path> For example: ssh example.com sudo cat /etc/shadow > sh…

Last year, Mozilla announced that they’re developing native vertical tabs for Firefox, and that it’s available in the Nightly release channel.

This does not have an impact on the functionality, and frees up space in the menu bar for other things.

If you run either of the following queries on PostgreSQL 16 or higher: SHOW LC_COLLATE; SELECT CURRENT_SETTING('LC_COLLATE'); You’ll see the following error message: ERROR: unrecognized configuration parameter "lc_collate" The LC_COLLATE parameter was r…

Power management Some Radeon cards have aggresive power saving profiles switched on by default.

Working sensors!

*Masquerading as the elephant in the room* Introduction In Part 1 we implemented the server handshake in Python.

Photo by Namukolo Siyumbwa on Unsplash Running CloudNativePG (CNPG) allows you to run a replicated PostgreSQL cluster with similar characteristics to a production employment on your personal machine.

Photo by Rita Candeias on Unsplash Having moved to the Netherlands a while back and spending some time in Amsterdam, I was wondering about the origin of the name of the most famous park in the Netherlands, Vondelpark.

Ever wondered what happens if you switch an UNLOGGED PostgreSQL table to LOGGED while replication is active?

Photo by Caterina sanders on Unsplash “You know what’s weird?

The standard way of updating all fields on Windows is to select all and press F9.

Rather than checking the expiration of the certificate on disk, we’ll connect to the server and get the live certificate instead.

During a PostgreSQL backend failover, you might find that PgPool-II becomes unresponsive, and that a process listing shows one or more PgPool-II processes as being <defunct>: postgres 3683365 0.0 0.0 0 0 ?

Normally Ansible doesn’t allow for the following: --- webservers: hosts: web-01 web-02 Instead of using the hyphen in the YAML host key, you use the inventory name as an alias, and then have the actual hostname in the ansible_host field for SSH purpo…

If it has worked up until this point, there’s no need for re-learning remote settings (either on the TV or the Apple TV).

Let’s assume you have a username user_a, with a database name database_a.

Version 2.17 of Ansible was released on the 20th of May 2024.

These are the apps I install on every new Mac, and this post serves as my personal reference list (as with many other posts on this blog).

“How did it get late so soon?”

Photo by Jandira Sonnendeck on Unsplash If you find yourself in the position where you need a full vacuum, you’re probably already looking at the number of dead tuples to have reached that conclusion.

If you’re successfully authenticating with PgPool-II, but receive the following message: Unable to get session context It means that you’ve likely not specified the correct connection database.

Peeking into the janitor’s closet Photo by Richard Jacobs on Unsplash Tuning the PostgreSQL autovacuum concerns a delicate balance between the kind of workloads running and the performance characteristics of the system.

If you find that, for some reason, an INSERT with a sequence value fails with a duplicate key error, you need to resynchronise the sequence value with the contents of the table.

On the 8th of April, I requested a transfer of this domain from Gandi.net to EuroDNS, following the recent-ish changes Gandi made to mailbox services, and wanting to avoid future issues arising from the takeover of Gandi.net.

Die lirieke is nêrens elders korrek ingelees nie, dus skryf ek dit hier op. sit weg my kitaar en sluit die kroeg jaag die mense weg ek’s moeg gespeel ek het lank gewag vir dit wat verlore is ek moet nou huis toe laai die kar en sluit die boot sit vir Fokof

“No one is ever satisfied where he is.” – Antoine de Saint-Exupéry The classic issue with an unreachable Ansible node is that SSH authorisation is either not configured or configured incorrectly.

Timeouts?

“There’s never enough time to do all the nothing you want.” ― Bill Watterson While vMotion migrations are not explicitly logged on Linux VMWare guests, there is a log message which correlates with these events.

PgPool raises the following error when attempting to run <a href="https://www.pgpool.net/docs/latest/en/html/pcp-detach-node.html">pcp_detach_node</a>: ERROR: degenerate backend request for node_id: 0 from pid [5307] is canceled because failover is disall…

“It’s still magic even if you know how it’s done.” – Terry Pratchett There’s a litany of shortcuts when it comes to technical work.

On perpetrating protocol mimicry It's surprisingly tricky to decide where to put a moustache on an elephant Introduction Today we’ll have a look at the PostgreSQL message flow, and implement a minimum workable server in Python.

To most developers, interacting with an API endpoint via HTTP(s) is something they’ve always done via libraries written by other people.

The flags of Namibia and Norway, respectively These two countries have inherited a curse.

“Begin at the beginning," the King said, very gravely, “and go on till you come to the end: then stop.”

Consider the following, fairly standard Gunicorn unit file: [Unit] Description=gunicorn daemon Requires=gunicorn.socket After=network.target [Service] User=www-data Group=www-data WorkingDirectory=/var/www/app ExecStart=/var/www/app/production/bin/gunico…

Changes made to the schema definition on the primary will not automatically reflect in the secondary.

Querying the primary We can query pg_stat_replication, and map the documented strings to numeric values – Prometheus uses numeric metrics, we’ll map them back to strings in Grafana: SELECT slot_name, application_name, client_addr, CASE WHEN state = '…

After a recent NFS issue I saw the following warnings in my Telegraf logs, and the disk metrics stopped being collected: W!