Hi Kunai, On Thursday, September 15, 2016 at 7:49:18 AM UTC+2, Kunal Deshpande wrote: > > Few questions on back pressure > 1. While using Flows in akka-streams using .via will a downstream flow > apply back pressure to a flow upstream or is back pressure only signaled to > a Source? >
Backpressure is applied everywhere inside of akka-stream and also across boundaries using the more generic reactive-streams interfaces (Publisher, Subscriber). The details how much backpressure is exactly propagated (or which buffers are around) are not so easy to predict, though. Still everything in akka-stream should use bounded memory. > 2. Will exceptions in a Flow trigger back pressure > No, exceptions will kill the complete materialized flow. Note, that an exception propagating through the stream in downstream direction may also overtake elements which are buffered but may not have been delivered. (Maybe, the question was also "can exception propagation be delayed by backpressure" and the answer to that is "no". > 3. Is there a mathematical way to represent back pressure and is it > consistent across different reactive streams implementations? > I don't know whether someone has already come up with a mathematical model of reactive streams semantics. If you read the spec you can see that implementations have a lot of freedom of how to implement backpressure concretely. E.g. one detail of the akka-stream implementation is that akka-stream will request and buffer a few elements at the upstream side of an asynchronous boundary. Other implementations may choose other strategies how many elements to request in one go. HTH, Johannes -- >>>>>>>>>> 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 akka-user+unsubscr...@googlegroups.com. To post to this group, send email to akka-user@googlegroups.com. Visit this group at https://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
