Exuma parent
This is literally one of those topics I have to come back and read time and time and time again every time I need it like 2 times a year. Maybe this article will finally make it stick.
Possibly. I tried hard to have some memorable examples.
But I'll be honest: Every time I got review comments (or re-reviewed myself), it took a bit of time for my brain to warm up again into "transaction mode".
The big lesson may that concurrent transactions are pretty hard to reason about without external assistant like diagrams or test scenarios. I really like the system Postgres uses for transaction testing (AKA - deterministic simulation testing). Create scenario that match your business logic and then run them serially but with different ordering of statements and make sure the results are as you expect.
this! never sticks for long, and I like the way this article flows in explaining isolation levels. definitely bookmarking it to get back to it later when needed.
I've been dealing with transactions regularly in the past few years, but not constantly, as things work correctly most of the time. And I still need to refresh my memory pretty much every time I go back to revisit some transactional code, or to answer any non-trivial questions about it.
So I guess it's just the way it is :)