[amw-zero]

Hello, I wrote the post.

I don’t claim to be a banking expert, but I did work at a payment processor that handled real money, and we used “select for update” extensively.

We also (obviously) used a ledger, but “just let everyone overdraft whenever” wasn’t something that the executives of the company thought was a good idea. So we did try and prevent insufficient funds errors as much as possible.

I personally witnessed several scenarios where the company lost a notable amount of money, (not only rated to concurrency bugs of course) and it’s a pretty bad feeling.

Anyway, I’m legitimately curious to know from people who worked at larger banks perhaps. How is weak transaction isolation not a problem for banks?