[adrianco]

I was a fly on the wall as this work was being done and it was super interesting to see the discussions. I was also surprised that Jepsen didn’t find critical bugs. Clarifying the docs and unusual (intentional) behaviors was a very useful outcome. It was a very worthwhile confidence building exercise given that we’re running a bank on Datomic…

[SOLAR_FIELDS]

Given that Rich Hickey designed this database the outcome is perhaps unsurprising. What a fabulous read - anytime I feel like I’m reasonably smart it’s always good to be humbled by a Jensen analysis

[nine_k]

A good design does not guarantee the absence of implementation bugs. But a good design can make introducing bugs harder / less probable. This must be the case, and then it's a case to study and maybe emulate.

[fiatjaf]

What bank is that, if I may ask?

[loevborg]

https://building.nubank.com.br/functional-programming-with-c...

[swah]

First brazilian fully digital bank, got pretty big in a decade.

I'd love to hear the story from the first engineers, how they got support for this, etc. They never did tech blog posts though...

[belter]

> I was also surprised that Jepsen didn’t find critical bugs.

From the report..."...we can prove the presence of bugs, but not their absence..."

[jupp0r]

In practical terms, if you are a database and Jepsen doesn't find any bugs, that's as much assurance as you are going to get in 2024 short of formal verification.

[vasco]

That's consistent with the usual definition of "finding" anything.

[cdchn]

"Absence of evidence is not evidence of absence."

[killingtime74]

Did you not do this work yourself before you started running the bank on it?

[cdchn]

I doubt any organization that isn't directly putting lives on the line are testing database technology as thoroughly and competently as Jepsen. Banks jobs are to be banks, not be Jepsen.