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Date: Tue, 30 Mar 2010 14:48:21 +0600
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Subject: Re: Poor performance; PHP & Thrift to blame
From: Rauan Maemirov <rauan@maemirov.com>
To: user@cassandra.apache.org
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What about APC? Did you turn it on?

2010/3/30 Julian Simon <jsimon@jules.com.au>:
> Hi,
>
> I've been trying to benchmark Cassandra for our use case and have been
> seeing poor performance on both writes and (extremely) poor
> performance on reads.
>
> Using Cassandra 0.51 stable & thrift-0.2.0.
>
> It turns out all the CPU time is going to the PHP client process - the
> JVM operating the Cassandra server isn't breaking much of a sweat.
>
> For reads the latency is often up to 1 second to fetch a row
> containing ~2000 columns, or around 300ms to fetch a 500-column wide
> row. =A0This is with get_slice(), and a predicate specifying the start &
> finish range.
>
> Using cachegrind and inspecting the code inside the Thrift bindings
> makes it pretty clear why the performance is so bad, particularly on
> reads. The biggest culprit is the translation code which casts data
> back and forth into binary representations for sending over the wire
> to the Cassandra server.
>
> There seems to be some 32-bit specific code which iterates heavily
> apparently due to a limitation in PHPs implementation of LONGs.
>
> However, testing on a 64-bit host doesn't yield any performance improveme=
nt.
>
> More surprisingly, if I compile and enable the PHP native thrift
> bindings (following this guide
> https://wiki.fourkitchens.com/display/PF/Using+Cassandra+with+PHP)
> read performance actually degrades by another 50%. =A0I have verified
> that the Thrift code is recognizing and using the native PHP functions
> provided by the library.
>
> I've tested all of this on both 32-bit and 64-bit installations of
> both PHP 5.1 & 5.2. =A0Results are the same in all cases.
>
> My environment is on vanilla CentOS 5.4 server installations inside
> VMWare on a 4 core 64bit host with plenty of RAM and fast disks.
>
> Has anyone been able to produce decent performance with PHP &
> Cassandra? =A0If so, how have you done it?
>
> Thanks,
> Jules
>