4 ms·

The rules haven't changed, its just that its always about the details. Most services, short of financial ones, choose to sacrifice consistency for availabilty.

The rules haven't changed, its just that its always about the details. Most services, short of financial ones, choose to sacrifice consistency for availabilty. Example being social networks, it doesn't matter if I get "inconsistent" social media feeds depending on where I am because my European friends posts haven't had time to propogate across the database shard. OTOH financial systems, you best believe they are going to choose consistency 9 times out of 10. Exceptions being being very small amounts. I don't want someone to exploit network/node downtime in order to steal millions of dollars. But the reality is that network outages, rarely last very long. Then its just a matter of making sure the nodes themselves are reliable.

marcosdumay 3y ago
Financial systems have been exchanging coerence for availability for milenia. It's just recently that anybody started to care about instantaneus coerence, instead of eventual.
- erikerikson 3y ago
  > coerence Did you mean coherence? As in consistency? I'd have autocorrected in reading except that you wrote it twice which implies intention. However a quick search didn't turn up a definition.
  - marcosdumay 3y ago
    Yep, English is not my first language.
    - erikerikson 3y ago
      No problem, thanks for learning it.
- SJC_Hacker 3y ago
  Like I said, depends on the amount. But I remember the days when you had to wait sometimes several days for a check to clear before the funds were available in your account. Of course you could always write bad checks - but payee was on the hook for the fraud, not the bank ...
jasonwatkinspdx 3y ago
There are situations that social networks need to worry about, consistency wise. Imagine a newly battered spouse unfriends their partner before making a post explaining why they're getting a divorce. If these two events get mixed up the perpetrator can end up reading the post. Also, ironically enough, most of the global financial system actually operates very inconsistently. It can take days for transactions to clear, and there's a bazillion quirks based on local law and bank policy. So in practice banks use double entry accounting with reconciliation. If something got messed up they issue a new compensating transaction.

marcosdumay 3y ago

Financial systems have been exchanging coerence for availability for milenia. It's just recently that anybody started to care about instantaneus coerence, instead of eventual.

erikerikson 3y ago
> coerence Did you mean coherence? As in consistency? I'd have autocorrected in reading except that you wrote it twice which implies intention. However a quick search didn't turn up a definition.
- marcosdumay 3y ago
  Yep, English is not my first language.
  - erikerikson 3y ago
    No problem, thanks for learning it.
SJC_Hacker 3y ago
Like I said, depends on the amount. But I remember the days when you had to wait sometimes several days for a check to clear before the funds were available in your account. Of course you could always write bad checks - but payee was on the hook for the fraud, not the bank ...

jasonwatkinspdx 3y ago

There are situations that social networks need to worry about, consistency wise. Imagine a newly battered spouse unfriends their partner before making a post explaining why they're getting a divorce. If these two events get mixed up the perpetrator can end up reading the post. Also, ironically enough, most of the global financial system actually operates very inconsistently. It can take days for transactions to clear, and there's a bazillion quirks based on local law and bank policy. So in practice banks use double entry accounting with reconciliation. If something got messed up they issue a new compensating transaction.