(based on a conversation with a colleague, and a bit of Twitter)
Where I work, we are using MySQL a lot. The databases are being organized in replication hierarchies, and each hierarchy is a tree topology with a single primary and a number of intermediate replicas.
»If at all possible, we build databases so that the working set of the database fits into memory.« What does that even mean?
Das Kind möchte ein Programm zum Üben von Rechenaufgaben sehen. Nun gut. Hier ist eine Version in PyQt5.
When you insert data into a database and run COMMIT you expect things to be there: Atomically, Consistent, Isolated and Durable, like Codd commanded us 40 years ago, but also quickly. There is a surprising amount of sophistication being poured into this, but since I do not want to shame MongoDB and Redis developers in this post, I am not going to talk about that much in this place.
Where I work, we try to run databases in a memory saturated way. That is, we try to provide so much memory that the working set of the database is memory resident, or in other words, the number of disk reads after an initial warmup is no longer dependent on the database load.
The DBA experience at work suggests that every single schema at some point in its lifecycle holds a queue table. These are tables in which some processes (the “producers”) put rows, which a swarm of other processes (the “consumers”) lock and consume.
When people ask for my mail address, they usually get a personalized address from me. That is particularly true for all commercial email. So you don’t get to send mail to my main account, but to kris-yourbusiness@koehntopp.de, and that will end up going into INBOX.special.yourbusiness. At least until it leaks, receives spam or is otherwise burned. In which case I will short it out and route all incoming mail on that address to /dev/null. Here is how it is done.
Deutschland ist im Lockdown, die Schulen sind endlich geschlossen und es wird remote unterrichtet. Weil es Deutschland ist, passiert das in jedem Bundesland anders und uneinheitlich. In Baden-Württemberg verwendet man Moodle. Wer sich da drunter nichts vorstellen kann, kann es sich hier ansehen.
My son wants labyrinths. Ok, let’s make them like it’s the first semester.
Heise writes an introduction to bash programming (in german):
This is the english version of a 2007 article.
Olya Kudriavtseva has an ugly christmas sweater:
Kalenderwoche 51/2020: Lockdown mit Schulschließungen. Nachdem es im März schon einmal Schulschließungen wegen Corona gab, und dort die Defizite technischer und organisatorischer Natur offenbar wurden, hat man in Deutschland die Zeit genutzt und sich auf die vorhergesagte 2. Welle vorbereitet, die jetzt genau eingetroffen ist. Deutschland ist schließlich nicht nur das Land der Dichter und Denker, sondern auch ein Land der Ingenieure und Tüftler, und bekannt für seine funktionierende und effiziente Bürokratie.
So this happened: CentOS Project shifts focus to CentOS Stream
The tables in PERFORMANCE_SCHEMA (P_S) are not actually tables. You should not think of them as tables, even if your SQL works on them. You should not JOIN them, and you should not GROUP or ORDER BY them.
There was a question at work about MySQL backups and restore. I needed to explain more.
These installation notes are mostly a note to myself, documenting the installation process of a Gitlab Omnibus Container in Docker, plus Gitlab Runners.
At work, I am in an ongoing discussion with a number of people on the Observability of Outliers. It started with the age-old question “How do I find slow queries in my application?” aka “What would I want from tooling to get that data and where should that tooling sit?”
I have been asked to document my home sensor network. Being married to a person with a background in web security sets boundary conditions:
