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From Jeremiah Jordan <JEREMIAH.JOR...@morningstar.com>
Subject RE: Write performance compared to Postgresql
Date Tue, 03 Apr 2012 16:08:02 GMT
So Cassandra may or may not be faster than your current system when you have a couple connections.
 Where it is faster, and scales, is when you get hundreds of clients across many nodes.

See:
http://techblog.netflix.com/2011/11/benchmarking-cassandra-scalability-on.html

With 60 clients running 200 threads each they were able to get 10K writes per second per server,
and as you added servers from 48-288 you still got 10K writes per second, so the aggregate
writes per second went from 48*10K to 288*10K

-Jeremiah

________________________________________
From: Jeff Williams [jeffw@wherethebitsroam.com]
Sent: Tuesday, April 03, 2012 10:09 AM
To: user@cassandra.apache.org
Subject: Re: Write performance compared to Postgresql

Vitalii,

Yep, that sounds like a good idea. Do you have any more information about how you're doing
that? Which client?

Because even with 3 concurrent client nodes, my single postgresql server is still out performing
my 2 node cassandra cluster, although the gap is narrowing.

Jeff

On Apr 3, 2012, at 4:08 PM, Vitalii Tymchyshyn wrote:

> Note that having tons of TCP connections is not good. We are using async client to issue
multiple calls over single connection at same time. You can do the same.
>
> Best regards, Vitalii Tymchyshyn.
>
> 03.04.12 16:18, Jeff Williams написав(ла):
>> Ok, so you think the write speed is limited by the client and protocol, rather than
the cassandra backend? This sounds reasonable, and fits with our use case, as we will have
several servers writing. However, a bit harder to test!
>>
>> Jeff
>>
>> On Apr 3, 2012, at 1:27 PM, Jake Luciani wrote:
>>
>>> Hi Jeff,
>>>
>>> Writing serially over one connection will be slower. If you run many threads
hitting the server at once you will see throughput improve.
>>>
>>> Jake
>>>
>>>
>>>
>>> On Apr 3, 2012, at 7:08 AM, Jeff Williams<jeffw@wherethebitsroam.com> 
wrote:
>>>
>>>> Hi,
>>>>
>>>> I am looking at cassandra for a logging application. We currently log to
a Postgresql database.
>>>>
>>>> I set up 2 cassandra servers for testing. I did a benchmark where I had 100
hashes representing logs entries, read from a json file. I then looped over these to do 10,000
log inserts. I repeated the same writing to a postgresql instance on one of the cassandra
servers. The script is attached. The cassandra writes appear to perform a lot worse. Is this
expected?
>>>>
>>>> jeff@transcoder01:~$ ruby cassandra-bm.rb
>>>> cassandra
>>>> 3.170000   0.480000   3.650000 ( 12.032212)
>>>> jeff@transcoder01:~$ ruby cassandra-bm.rb
>>>> postgres
>>>> 2.140000   0.330000   2.470000 (  7.002601)
>>>>
>>>> Regards,
>>>> Jeff
>>>>
>>>> <cassandra-bm.rb>
>


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