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From "B. Todd Burruss" <bburr...@real.com>
Subject Re: Tuning Cassandra
Date Mon, 10 May 2010 17:17:45 GMT
have you put your commit log on a disk by itself?  not a logical 
partition shared by oracle or cassandra "data".  this will make a 
difference, as you don't want the cassandra commit logs competing with 
other OS and oracle I/O.  look in storage-conf.xml and see if you can 
move this.

also check "MemtableThroughputInMB".  if you are doing a _lot_ of writes 
you probably want to jack this up a bunch to get through the migration, 
then put it back down for normal operation.  the default out of the box 
is too low i believe.

On 05/10/2010 02:05 AM, David Boxenhorn wrote:
> I read something like 80,000 rows from Oracle and write them to 
> Cassandra in chunks of 1000 rows - so I'm supposedly working to 
> Cassandra's strength and Oracle's weakness.
>
> Reading 1000 rows from Oracle is "instantaneous", writing them takes 
> maybe 30 seconds. Not too much data per row, maybe 1K.
>
>
>
> On Mon, May 10, 2010 at 11:48 AM, Ran Tavory <rantav@gmail.com 
> <mailto:rantav@gmail.com>> wrote:
>
>     Hector uses tsocket. not sure what you mean by "buffered" - is
>     that framed? Hector by default does not use framed.
>     The code is here if you'd like to have a look
>     http://github.com/rantav/hector/blob/master/src/main/java/me/prettyprint/cassandra/service/CassandraClientFactory.java#L77
>
>     However, I find it hard to believe that the actual connection is
>     the slowing factor.
>
>     Roughly speaking, cassandra is fast on writes and slow on reads.
>     Exact numbers are per-scenario so it's hard to say, but if you
>     only write and objects are small then from my experience you
>     should expect a few k writes per second on a single host. How much
>     do you see?
>
>     There are many configuration factors and they all depend on
>     expected usage and available h/w.
>
>
>     On Mon, May 10, 2010 at 11:27 AM, vd <vineetdaniel@gmail.com
>     <mailto:vineetdaniel@gmail.com>> wrote:
>
>         What is the complete code string you are using to connect with
>         cassandra from Java code
>
>
>
>
>         On Mon, May 10, 2010 at 1:49 PM, David Boxenhorn
>         <david@lookin2.com <mailto:david@lookin2.com>> wrote:
>
>             I don't know what "TSocket or the buffered one" means.
>             Maybe I should know?
>
>             I'm using Hector. Does that explain anything?
>
>             On Mon, May 10, 2010 at 11:15 AM, vd
>             <vineetdaniel@gmail.com <mailto:vineetdaniel@gmail.com>>
>             wrote:
>
>
>                 Hi
>
>                 what is it that you are using to connect with
>                 cassnadra TSocket or the buffered one ?
>
>
>                 ____________________________________
>
>                 _______________________________________
>
>
>
>
>                 On Mon, May 10, 2010 at 1:29 PM, David Boxenhorn
>                 <david@lookin2.com <mailto:david@lookin2.com>> wrote:
>
>                     I'm running Java on the client, jdbc queries on
>                     Oracle, Hector on Cassandra.
>
>                     The Cassandra and Oracle database designs are
>                     radically different, as you might guess.
>
>                     I have no doubt that Cassandra can be tuned, in a
>                     multiple-server cluster, to have superior
>                     throughput (that's why I'm doing it!). But for
>                     now, it's really frustrating my development effort
>                     that Cassandra is so slow. Can't I get it up to
>                     twice as slow as Oracle in my configuration?
>
>                     On Mon, May 10, 2010 at 10:47 AM, vd
>                     <vineetdaniel@gmail.com
>                     <mailto:vineetdaniel@gmail.com>> wrote:
>
>                         Hi David
>
>                         If I may ask...how do you plan to import data
>                         from oracle to cassandra ?
>                         As answer AFAIK cassandra's true ability comes
>                         into play when running on more than one
>                         machine...and please share how you are making
>                         comparisons like on writes or reads from
>                         cassandra.
>
>
>
>                         _______________________________________
>                         _______________________________________
>
>
>
>
>
>                         On Mon, May 10, 2010 at 1:04 PM, David
>                         Boxenhorn <david@lookin2.com
>                         <mailto:david@lookin2.com>> wrote:
>
>                             I'm running Oracle and Cassandra on my
>                             machine, trying to import my data to
>                             Cassandra from Oracle.
>
>                             In my configuration Oracle is about ten
>                             times faster than Cassandra. Cassandra has
>                             out-of-the-box tuning.
>
>                             I am new to Cassandra. How do I begin
>                             trying to tune it?
>
>                             Thanks.
>
>
>
>
>
>
>
>


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