Die wunderbare Welt von Isotopp

Pizza, People, Projects and Processes

- June 15, 2020
An older talk from 2 years ago, which for some reason I was not able to find in the blog. For reasons that do not need exploration at this junction I had to explain Processes and Process Maturity some time ago, and a colleague asked me to put my thinking into a talk. So this is going to be boring, because you are likely to know most of this already, but on the other hand, it is good to be on the same page when it comes to models and vocabulary.

Where do the JOINs go?

- June 10, 2020
I was asking on Twitter: Are you a Developer and understand (Micro-) Services? I am a database person and a bit simple, and I have a genuine Question: When moving to a services architecture, where do the JOINs go? I gave the following context: A simple shop So you sell stuff, that is, you have an orders table o with an oid, which stores a customer id cid from a customers c table, and an article id aid, from an articles table a and a count cnt.

Sonos just got complicated

- June 9, 2020
So this morning the 08:10 alarm in the living room did not go off. It was set to remind the son that it is time to get going for school. We noticed in time, but when I looked into the “Why?” things got interesting. That alarm is a chime from the household Sonos system, and when I investigated, I got this: Sonos did the split and upgraded/rebranded their controller operating system to S1.

Cloud and Energy

- June 8, 2020
In Data Centers and Energy I wrote about Hyperscaler Data Centers and Open Compute, and how they bring down the PUE of data centers, making them more efficient, and in Streaming and Energy I followed up on this, explaining how Netflix energy usage fits into this. Now the Uptime Institute has released a study that claims “Data center energy efficiency gains have flattened out”. It is summarized as: The average power usage effectiveness (PUE) ratio for a data center in 2020 is 1.

Waffle House Index of Tooling

- June 8, 2020
Charity Majors was on fire and on target, again : What is a Waffle House Index ? The Waffle House Index is an informal metric named after the Waffle House restaurant chain and is used by the Federal Emergency Management Agency (FEMA) to determine the effect of a storm and the likely scale of assistance required for disaster recovery. A “Waffle House Index for Tooling” would be an indicator how bad the situation on the ground in an IT department is.

Fixing "ip netns" for docker

- June 7, 2020
So I want to monitor my Jitsi Videobridge to get some useful statistics. The instructions say to enable Videobridge statistics and then grab stuff from port 8080. Ok, I think I did that, but it did not work. Time to dig into the container network config. And while I have a lot of network namespaces, they are unknown to ip netns, as can be seen when asking for a list. When we define a network namespace with ip netns, it will symlink the assigned name from /var/run/netns/<name> to /proc/<pid>/ns/net of the process that leads that namespace.

Optimistic locking

- June 4, 2020
A question from Reddit’s /r/mysql: Hey, I was planning to make a dashboard, where Users are subjected to make edits on their profiles every now and then, and I expect a high volume of requests to the database. Having worked previously with MySQL for another Dashboard, I encountered errors for: Maximum user connections - when I connected to the database only while query was to be executed

Fertig gelesen: Rolf Ulrici

- June 3, 2020
Als ich noch ein ganz kleiner Kris war, habe ich die Schülerbüchereien von mehreren Schulen durchgelesen und mich dann über die Gemeindebücherei hergemacht. Es ist jetzt mehr als 40 Jahre her, daß ich da im Schülerteam mitgearbeitet habe, aber die Chefin, die damals gerade angefangen hatte und die auch das Schülerteam begründet hat, ist immer noch da und macht ihren Job. Das ist unglaublich großartig. Groß geworden bin ich unter anderem mit den Büchern von Rolf Ulrici , Raumschiff Monitor und Erdschiff Giganto.

MySQL store_result and use_result

- June 1, 2020
A question from Reddit’s /r/mysql led to a longer discussion of cursors and how they are implemented in MySQL, and what the advantages and drawbacks are. The OP probably had a slow query, but was misphrasing the question: I am having performance problems where my cursor is taking 6-8 seconds to go through a hundred rows. I think this is because I am also using while loops to loop through JSON objects to pull information.

Time Machine Editor

- May 26, 2020
I have an embedded Mac mini, it drives the local TV screen by doing OpenVPN to Germany, Netflix, Amazon and the local Subsonic . It does not really do much with the local disk, and it does not need to wake up every hour to make a Time Machine backup over the network. To change the backup interval, install Time Machine Editor . Time Machine Editor can change the Time Machine Backup interval.

Air Quality Sensors

- May 25, 2020
In an earlier episode I asked for Plugs with Wi-Fi and ended up with Gosund and Tasmota . Considering this to be a success, I asked the Twitters for Temperature and Humidity Sensors. Of course, this got complicated. Now that I have Powermeter Plugs everywhere: What are good sensors for temperature, humidity and CO2 that can be tasmotified? Wi-Fi, http or mqtt? I was pointed to Xiaomi Aqara , but these do not do Wi-Fi, but Zigbee - whatever that is, it is spoken by Zigbee USB Gateway Sticks and works with Raspi.

Gosund and Tasmota

- May 20, 2020
(continued from Plugs with Wi-Fi ) So the Gosund plugs came, as did the Raspi 4. I did cancel the Shelly plug and decomissioned the TP-Link Kaka, because Tasmota on Gosund is awesome and the Gosund hardware is dirt cheap. Power consumption of the local data grave, with too old a mainboard and CPU and way too much storage But lets start at the beginning: 4 Pack of Gosund SP111 V1.

Note to self: Archiving Discord Chats

- May 18, 2020
When the Coronacrisis began, a good friend of mine started a Discord server and brought the band back together. As with any of the Coronavirus Quarantine Chats, the initial discussion revolved around baking proper bread. I wanted to archive this, so I needed a way to download Discord chat histories for archive. The DiscordChatExporter can do that, and doing this was actually easy. I needed Docker my Discord User Token No Discord Bot Token The Discord Channel ID and then did a small starter script:

Deleting data from MySQL

- May 13, 2020
I have been pointed at the following question: »Has anyone ever used mySQL events to auto-delete rows from a table after set period? Wondering your experience of doing this.« There are two ends to this question: expiring data from a MySQL table doing this with the event scheduler Mass-deleting data from InnoDB You can of course delete data from a table using the SQL DELETE statement with an arbitrary WHERE-clause at any time:

Plugs with Wi-Fi

- May 12, 2020
So we are baking bread, and for that we have a Wiesheu minimat oven that comes in at a full 16A - supposedly it is using 3kW or more peak plus the condenser hood that comes in at another 500W top power draw. On the other hand, when running the thing is hardly lukewarm, it is running much cooler than the Neff household oven/microwave combo we have. Wiesheu minimat with condenser hood.

Data Access Programs and Pre-SQL systems

- May 1, 2020
Let’s have a look at very old database systems. Things like dBase or compatible systems (“xBases”) allowed to manipulate record based files (with indexes) in a procedural way. What does that mean? xBase The system allows developers to create files that contain a well defined (fixed size) record structure, basically an array of struct on disk, often together with the definition of on-screen masks designed to show a single record and a (searchable) list of records.

Fertig gelesen: Deathworlders

- May 1, 2020
In the foreword to his short story “With Friends Like These" , Alan Dean Foster writes HFY? My favorite writer of science fiction was, and still is, the inimitable Eric Frank Russell. When I was turning in short stories to the magazines instead of papers to my college professors and collecting rejection slips instead of credits and grades, I often wondered why Russell had stopped writing. I miss him.

Fertig gelesen: Delta-V and Space Barons

- May 1, 2020
A lot of super rich people are currently busy blowing their money into space. Who are these people, and what drives them? Space Barons , Christian Davenport, 10.99 Eur (Kindle) In Space Barons, Christian Davenport goes through the rather short list of super rich men who are trying to get private spacecraft flying, tells their history, successes and failures, and their motivations - or, in some cases, the story of the death of their dreams and how they drop out of the second, private space race.

Fertig gelesen: Die Krone der Sterne: Hexenmacht/Maschinengötter

- May 1, 2020
“Hexenmacht” (German Edition) and “Maschinengötter” (German Edition) are part 2 and 3 in the series “Die Krone der Sterne” (The Crown of Stars) by Kai Meyer. See Die Krone der Sterne for a review of part 1. Hexenmacht , Kai Meyer, 12.99 Eur (Kindle) Where part 1 spent a lot of time with world building and tourism, showing of the wonder and the atmosphere of the universe, part 2 is approaching from a different angle - we get a lot more action, and a lot less background.

Netflix does not bring down the Internet

- March 19, 2020
It’s Coronavirus Crisis and Netflix is killing us all, again. This time it’s not their excessive energy use , but their dreaded HD videos that are overloading the Internet. Or is it? It’s only Swisscom Supposedly Switzerland is considering Netflix shutdown to prevent Home Office workers from being disconnected. According to its own statements, on the first day of the quasi curfew in our neighboring country, Swisscom recorded an enormous increase in the load on the infrastructure.