Correct -- this is totally routine in fraud situations. (I spent much of the past five years working on fraud-detection code. The biggest thing I learned is that the financial system isn't even *remotely* as atomic as any modern programmer would expect. It isn't just that there are race conditions in the overall architectures -- it is that those races are often *days* long...)
On Mon, Mar 10, 2014 at 5:16 PM, Haoyi Li <[email protected]> wrote: > > Bank account transfers are not implemented using (distributed) > transactions by real banks, that is just an academic ivory tower example > ;-) In reality the bank will create a transfer command which is passed from > system to system, using safe hand-off techniques (i.e. the money really is > "in flight" for a while). If things go wrong, compensating commands are > injected which put the money back into the original account. > > In fact, when you "roll back" a bank account transaction, the bank may > just give you money out of its own pocket if the guy you transacted to has > taken the money out of an ATM in cash and fled the country. > > > On Mon, Mar 10, 2014 at 2:09 PM, Roland Kuhn <[email protected]> wrote: > >> >> 10 mar 2014 kl. 21:39 skrev Rob Nikander <[email protected]>: >> >> On Monday, March 10, 2014 5:21:48 AM UTC-4, Björn Antonsson wrote: >> >>> >>> The reason that Akka is moving away from transactions and doesn't >>> provide out of the box support for distributed transactions is that they >>> perform poorly in real life and promote a thinking that leads to a non >>> scaling design. >>> >>> To build systems without distributed transactions you need to apply a >>> different way of thinking about your systems. A good read on the subject is >>> this Position Paper by Pat Helland: Life beyond Distributed >>> Transactions<http://www-db.cs.wisc.edu/cidr/cidr2007/papers/cidr07p15.pdf> >>> . >>> >> >> Is there an example somewhere of how to do a bank account transfer, using >> this different way of thinking? Or should I just stay away from Akka if I >> need transactions of this sort? >> >> >> Bank account transfers are not implemented using (distributed) >> transactions by real banks, that is just an academic ivory tower example >> ;-) In reality the bank will create a transfer command which is passed from >> system to system, using safe hand-off techniques (i.e. the money really is >> "in flight" for a while). If things go wrong, compensating commands are >> injected which put the money back into the original account. >> >> In the end there is no way to stay away from the principles which make >> Akka seem different to you: distributed transactions do not really exist, >> they are always a slightly leaky illusion; that lies in the nature of >> distributed systems. You might want to check the CAP theorem (don't trust >> the wikipedia page) and Eric Brewer's follow-on >> article<http://www.infoq.com/articles/cap-twelve-years-later-how-the-rules-have-changed> >> (he >> discusses ATMs as well). >> >> Regards, >> >> Roland >> >> >> Rob >> >> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: >> http://doc.akka.io/docs/akka/current/additional/faq.html >> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >> --- >> You received this message because you are subscribed to the Google Groups >> "Akka User List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/d/optout. >> >> >> >> >> *Dr. Roland Kuhn* >> *Akka Tech Lead* >> Typesafe <http://typesafe.com/> - Reactive apps on the JVM. >> twitter: @rolandkuhn >> <http://twitter.com/#!/rolandkuhn> >> >> -- >> >>>>>>>>>> Read the docs: http://akka.io/docs/ >> >>>>>>>>>> Check the FAQ: >> http://doc.akka.io/docs/akka/current/additional/faq.html >> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user >> --- >> You received this message because you are subscribed to the Google Groups >> "Akka User List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/akka-user. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > >>>>>>>>>> Read the docs: http://akka.io/docs/ > >>>>>>>>>> Check the FAQ: > http://doc.akka.io/docs/akka/current/additional/faq.html > >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user > --- > You received this message because you are subscribed to the Google Groups > "Akka User List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/akka-user. > For more options, visit https://groups.google.com/d/optout. > -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
