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From Carlos Alvarez <cbalva...@gmail.com>
Subject Re: New User: OSX vs. Debian on Cassandra 0.5.0 with Thrift
Date Sat, 24 Apr 2010 21:07:25 GMT
On Fri, Apr 23, 2010 at 4:29 PM, Heath Oderman <heath@526valley.com> wrote:
> Really interesting find.
> After Jonathan E. suggested py_stress and it seemed clear the problem was in
> my .net client I spent a few days debugging the client in detail.
> I ended up changing my CassandraContext instantiation to use a
>           TBuffferedProtocol(TSocket) instead of a
>           TSocket directly.
> The difference was *dramatic*.

Heath, thank you for this awesome tip. I also have a dotNet client and
I will make an experiment with your findings.

Do you mean TBufferedTransport(TSocket)? I was unable to find
TBufferedProtocol in Thrift generated code.

Looking inro the code of both classes (TBufferedTransport and TSocket)
I saw the former uses buffered streams and the latter doens't (which
is pretty clear taking into account its names :-) ).

Also, I've seen that a operation (for instance, a get) implies many
writes to the underlying stream: a WriteMessageBegin which in turns is
three writes to the stream, a WriteFieldBegin (2 writes) and so on. If
every of them is a actual roundtrip to the network and waits for the
ACK you could find a big difference between these two clases.

It explains the improvement but not the diference you experienced.
Assuming both boxes are in the same net, it could had been caused by
diferent quality network hardware/drivers. Even in the same net,
windows could assign diferent MTU size and Receive Window size
depending on the other end.

Again, thank you very much for pointing this direction (maybe,if the
test are sucessfull, it would deserve an update in the C# client
sample in the wiki).


Carlos.

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