> (and if the message is being decoded on the server site as a complete > message, then presumably the same resident memory consumption applies there > too). Yerp. And every row mutation in your batch becomes a task in the Mutation thread pool. If one replica gets 500 row mutations from one client request it will take a while for the (default) 32 threads to chew through them. While this is going on other client request will be effectively blocked.
Depending on the number of clients, I would start with say 50 rows per mutation and keep and eye of the *request* latency. Hope that helps. ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 9/12/2012, at 7:18 AM, Ben Hood <0x6e6...@gmail.com> wrote: > Thanks for the clarification Andrey. If that is the case, I had better ensure > that I don't put the entire contents of a very long input stream into a > single batch, since that is presumably going to cause a very large message to > accumulate on the client side (and if the message is being decoded on the > server site as a complete message, then presumably the same resident memory > consumption applies there too). > > Cheers, > > > Ben > > On Dec 7, 2012, at 17:24, Andrey Ilinykh <ailin...@gmail.com> wrote: > >> Cassandra uses thrift messages to pass data to and from server. A batch is >> just a convenient way to create such message. Nothing happens until you send >> this message. Probably, this is what you call "close the batch". >> >> Thank you, >> Andrey >> >> >> On Fri, Dec 7, 2012 at 5:34 AM, Ben Hood <0x6e6...@gmail.com> wrote: >> Hi, >> >> I'd like my app to stream a large number of events into Cassandra that >> originate from the same network input stream. If I create one batch >> mutation, can I just keep appending events to the Cassandra batch until I'm >> done, or are there some practical considerations about doing this (e.g. too >> much stuff buffering up on the client or server side, visibility of the data >> within the batch that hasn't been closed by the client yet)? Barring any >> discussion about atomicity, if I were able to stream a largish source into >> Cassandra, what would happen if the client crashed and didn't close the >> batch? Or is this kind of thing just a normal occurrence that Cassandra has >> to be aware of anyway? >> >> Cheers, >> >> Ben >>
