You have me thinking more. I wonder in practice if 3 sockets is any faster than 1 socket when doing nio. If your buffer sizes were small, maybe that would be the case. Usually the nic buffers are big so when the selector fires it is reading from 3 buffers for 3 sockets or 1 buffer for one socket. In both cases, all 3 requests are there in the buffers. At any rate, my belief is it probably is still basically parallel performance on one socket though I have not tested my theory…..My theory being the real bottleneck on performance being the work cassandra has to do on the reads and such.
What about 20 sockets then(like someone has a pool). Will it be any faster…not really sure as in the end you are still held up by the real bottleneck of reading from disk on the cassandra side. We went to 20 threads in one case using 20 sockets with astyanax and received no performance improvement(synchronous but more sockets did not improve our performance). Ie. It may be the case 90% of the time, one socket is just as fast as 10/20…..I would love to know the truth/answer to that though. Later, Dean From: Aaron Turner <synfina...@gmail.com<mailto:synfina...@gmail.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Monday, May 6, 2013 10:57 AM To: cassandra users <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: Re: hector or astyanax Just because you can batch queries or have the server process them out of order doesn't make it fully "parellel". You're still using a single TCP connection which is by definition a serial data stream. Basically, if you send a bunch of queries which each return a large amount of data you've effectively limited your query throughput to a single TCP connection. Using Thrift, each query result is returned in it's own TCP stream in *parallel*. Not saying the new API isn't great, doesn't have it's place or may have better performance in certain situations, but generally speaking I would refrain from making general claims without actual benchmarks to back them up. I do completely agree that Async interfaces have their place and have certain advantages over multi-threading models, but it's just another tool to be used when appropriate. Just my .02. :) On Mon, May 6, 2013 at 5:08 AM, Hiller, Dean <dean.hil...@nrel.gov<mailto:dean.hil...@nrel.gov>> wrote: I was under the impression that it is multiple requests using a single connectin PARALLEL not serial as they have request ids and the responses do as well so you can send a request while a previous request has no response just yet. I think you do get a big speed advantage from the asynchronous nature as you do not need to hold up so many threads in your webserver while you have outstanding requests being processed. The thrift async was not exactly async like I am suspecting the new java driver is, but have not verified(I hope it is) Dean From: Aaron Turner <synfina...@gmail.com<mailto:synfina...@gmail.com><mailto:synfina...@gmail.com<mailto:synfina...@gmail.com>>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>> Date: Sunday, May 5, 2013 5:27 PM To: cassandra users <user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>> Subject: Re: hector or astyanax On Sun, May 5, 2013 at 1:09 PM, Derek Williams <de...@fyrie.net<mailto:de...@fyrie.net><mailto:de...@fyrie.net<mailto:de...@fyrie.net>>> wrote: The binary protocol is able to multiplex multiple requests using a single connection, which can lead to much better performance (similar to HTTP vs SPDY). This is without comparing the performance of thrift vs binary protocol, which I assume the binary protocol would be faster since it is specialized for cassandra requests. Curious why you think multiplexing multiple requests over a single connection (serial) is faster then multiple requests over multiple connections (parallel)? And isn't Thrift a binary protocol? -- Aaron Turner http://synfin.net/ Twitter: @synfinatic http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Windows Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. -- Benjamin Franklin "carpe diem quam minimum credula postero" -- Aaron Turner http://synfin.net/ Twitter: @synfinatic http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Windows Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. -- Benjamin Franklin "carpe diem quam minimum credula postero"
