FWIW - I think this is actually more of a question about Thrift than about Cassandra. If I understand you correctly, you're looking for a async client. Cassandra "lives" on the other side of the thrift service. So, you need a client that can speak Thrift asynchronously.
You might check out the new async Thrift client in Java for inspiration: http://blog.rapleaf.com/dev/2010/06/23/fully-async-thrift-client-in-java/ Or, even better, port the Thrift async client to work for python and other languages. Dave Viner On Tue, Jul 27, 2010 at 8:44 AM, Peter Schuller <peter.schul...@infidyne.com > wrote: > > The idea is rather than calling a cassandra client function like > > get_slice(), call the send_get_slice() then have a non blocking wait on > the > > socket thrift is using, then call recv_get_slice(). > > (disclaimer: I've never used tornado) > > Without looking at the generated thrift code, this sounds dangerous. > What happens if send_get_slice() blocks? What happens if > recv_get_slice() has to block because you didn't happen to receive the > response in one packet? > > Normally you're either doing blocking code or callback oriented > reactive code. It sounds like you're trying to use blocking calls in a > non-blocking context under the assumption that readable data on the > socket means the entire response is readable, and that the socket > being writable means that the entire request can be written without > blocking. This might seems to work and you may not block, or block > only briefly. Until, for example, a TCP connection stalls and your > entire event loop hangs due to a blocking read. > > Apologies if I'm misunderstanding what you're trying to do. > > -- > / Peter Schuller >
