Yeah, you’re right, if its a single writer, then your code is correct.
Why is it always the same people in KV DB topics 
. Happy new year btw!
Asd
garrison
There are dozens of us! I’m really a relational model enjoyer though, KV is just a means to an end 
I’ll edit my post. Happy new year!
3
lcabrini
lcabrini
Aha! Yes, a locking mechanism is a must. In Go I used a mutex to lock during a write. That is what I wanted to be able to achieve in Elixir, but I’m not quite there yet. So GenServer is the best path then?
0
lcabrini
I’m not against using a file, but I’m quite biased towards using a db table. Not for any deep philosophical reason, just power of habit, I guess.In the root post, I did mention that the settings are backed up together with a database backup. That may be a form of justification.
0
lcabrini
It should be the case that there is only one writer, but I always prefer to play it safe just in case.
0
garrison
Of course you must trust your own application code, so if you legitimately know that there is only ever going to be a single process that changes settings then you don’t need to worry about it. The purpose of the GenServer is to ensure that there is only going to be a single process that changes settings, i.e. the correctness is tautological.
There are other techniques that could improve concurrency, like per-row locks, but I doubt that would be necessary in your case. Better to keep it simple.
0
Asd
To be honest, it all sounds like XY problem. Changing configuration and settings in runtime is a strange approach. And making these changes persistent is even more strange. Other thing is that such configuration changes may be just read once, then cached or stored in process state, making any change to settings partial and inconsistent
So, what are these settings exactly? How do you use them?
2
dimitarvp
Yeah, you beat me to it. We never got told the concrete problem that made OP think they need a simple persistent key/value store for runtime-changeable configuration.
0
cmo
Is it really that unusual to have user configurable settings in an application? I can’t imagine asking my users to restart the app, that other people may be using at the time, just to change a setting.
0