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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Network latency on Cassandra 0.7 (TFramedTransport)
Date Sat, 18 Sep 2010 08:43:46 GMT
Created https://issues.apache.org/jira/browse/THRIFT-904

On Fri, Sep 17, 2010 at 12:16 PM, Michael Greene
<michael.greene@gmail.com> wrote:
> This is the correct cause.  Reproducing your test gives 38-45ms in each of
> 10 runs.  If you run a profiler against it, you can see that the time is
> entirely spent blocking on receive in TStreamTransport.Read.
> Your test can be modified with the following line:
> coreTransport.TcpClient.NoDelay = true;
> After disabling Nagle's each test runs in < 1ms.
> Michael
> On Fri, Sep 17, 2010 at 9:57 AM, Peter Schuller
> <peter.schuller@infidyne.com> wrote:
>>
>> > The latency is about 200 ms on every request when I'm connected to
>> > another
>>
>> My first thought here was that maybe you're seeing the effects of
>> nagle[1] + delayed acks on the other side. On Unix, normally something
>> like a thrift client would set TCP_NODELAY on its socket to avoid the
>> problem. I'm not sure whether or not this is a reasonable hypothesis
>> with C# + Thrift on Windows. Sorry, I don't know what the easy fix is
>> either but perhaps it might help dig further.
>>
>> [1] http://en.wikipedia.org/wiki/Nagle's_algorithm
>>
>> --
>> / Peter Schuller
>
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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