alt Hacker NewsFresh reader here. I am very interested to learn more about your sentence
> We spent a lot of money finding out that a lock is more performant.
I want to hear about that journey.
> Besides, it's a btree.
I guess it's not a hash table, but I think the point of Vincent's post is still worth exploring. You and he both say that essentially a key/value store is mutexed, and the user's code runs inside that mutex. That is fascinating. Why would that be better? Clearly it is, or you wouldn't have spent the money. What controls did you put in place to ensure user code didn't blow up the performance, or did you even feel the need for such controls? Is WASM VM execution fast enough for this? Is there even a market for that? Who pays to put their code inside that mutex and why? I want to know more.
I don't have the whole story for you, but the key is that SpacetimeDB transactions are not interactive. The TigerBeetle team talks about this a lot as well.
The TL;DR is that because you're not holding locks across the network (as is the case in Postgres), your server code can complete transactions in single digit microseconds, rather than milliseconds. And the practical effect is you can do many more transactions per second as a result.