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From Dmitriy Lyubimov <dlie...@gmail.com>
Subject Re: 0.90 latency performance, cdh3b4
Date Fri, 22 Apr 2011 06:25:41 GMT
> I doubt that TCP doesn't perform well.  If you really believe so, can
> you provide a packet capture collected with:
> sudo tcpdump -nvi eth0 -s0 -w /tmp/pcap port 60020

Thanks, i will certainly try. However same class machine same data
same test locally vs. remote same subnet is de facto 100% difference.
I am just as puzzled. I did not expect this.

> Would you be open to trying asynchbase in your test case /
> application?  I haven't seen a case (yet) where you actually *need* to
> open multiple connections per RegionServer.  I expect that if the
> problem is an inefficiency in the HBase client, asynchbase might do
> better, and if it does not, its DEBUG logging level might shed some
> light on where the problem comes from.
> https://github.com/stumbleupon/asynchbase

I certainly would. Even more, i already read the code there  just a
bit although not enough to understand where the efficiency comes from.
Do you actually implement another version of RPC on non-blocking
sockets there?

Unfortunately i can't do much more than just 'try' any time soon as
the codebase is rather tightly coupled with current client. Migrating
code and tests would not be a one day effort. However, i certainly can
try with one test.
But if only i could solve the mysterious tcp lag in the datacenter, i
suspect my needs would be quite well covered with the standard client
as well.

Thank you very much for your help.

> --
> Benoit "tsuna" Sigoure
> Software Engineer @ www.StumbleUpon.com

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