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From Avi Kivity <...@scylladb.com>
Subject Re: scylladb
Date Fri, 10 Mar 2017 07:17:06 GMT
ScyllaDB engineer here.

C++ is really an enabling technology here. It is directly responsible 
for a small fraction of the gain by executing faster than Java.  But it 
is indirectly responsible for the gain by allowing us direct control 
over memory and threading.  Just as an example, Scylla starts by taking 
over almost all of the machine's memory, and dynamically assigning it to 
memtables, cache, and working memory needed to handle requests in 
flight.  Memory is statically partitioned across cores, allowing us to 
exploit NUMA fully.  You can't do these things in Java.

I would say the major contributors to Scylla performance are:
  - thread-per-core design
  - replacement of the page cache with a row cache
  - careful attention to many small details, each contributing a little, 
but with a large overall impact

While I'm here I can say that performance is not the only goal here, it 
is stable and predictable performance over varying loads and during 
maintenance operations like repair, without any special tuning.  We 
measure the amount of CPU and I/O spent on foreground (user) and 
background (maintenance) tasks and divide them fairly. This work is not 
complete but already makes operating Scylla a lot simpler.

On 03/10/2017 01:42 AM, Kant Kodali wrote:
> I dont think ScyllaDB performance is because of C++. The design 
> decisions in scylladb are indeed different from Cassandra such as 
> getting rid of SEDA and moving to TPC and so on.
>
> If someone thinks it is because of C++ then just show the benchmarks 
> that proves it is indeed the C++ which gave 10X performance boost as 
> ScyllaDB claims instead of stating it.
>
>
> On Thu, Mar 9, 2017 at 3:22 PM, Richard L. Burton III 
> <mrburton@gmail.com <mailto:mrburton@gmail.com>> wrote:
>
>     They spend an enormous amount of time focusing on performance. You
>     can expect them to continue on with their optimization and keep
>     crushing it.
>
>     P.S., I don't work for ScyllaDB.
>
>     On Thu, Mar 9, 2017 at 6:02 PM, Rakesh Kumar
>     <rakeshkumar464@outlook.com <mailto:rakeshkumar464@outlook.com>>
>     wrote:
>
>         In all of their presentation they keep harping on the fact
>         that scylladb is written in C++ and does not carry the
>         overhead of Java.  Still the difference looks staggering.
>         ________________________________________
>         From: daemeon reiydelle <daemeonr@gmail.com
>         <mailto:daemeonr@gmail.com>>
>         Sent: Thursday, March 9, 2017 14:21
>         To: user@cassandra.apache.org <mailto:user@cassandra.apache.org>
>         Subject: Re: scylladb
>
>         The comparison is fair, and conservative. Did substantial
>         performance comparisons for two clients, both results returned
>         throughputs that were faster than the published comparisons
>         (15x as I recall). At that time the client preferred to
>         utilize a Cass COTS solution and use a caching solution for
>         OLA compliance.
>
>
>         .......
>
>         Daemeon C.M. Reiydelle
>         USA (+1) 415.501.0198 <tel:%28%2B1%29%20415.501.0198>
>         London (+44) (0) 20 8144 9872
>         <tel:%28%2B44%29%20%280%29%2020%208144%209872>
>
>         On Thu, Mar 9, 2017 at 11:04 AM, Robin Verlangen <robin@us2.nl
>         <mailto:robin@us2.nl><mailto:robin@us2.nl
>         <mailto:robin@us2.nl>>> wrote:
>         I was wondering how people feel about the comparison that's
>         made here between Cassandra and ScyllaDB :
>         http://www.scylladb.com/technology/ycsb-cassandra-scylla/#results-of-3-scylla-nodes-vs-30-cassandra-nodes
>         <http://www.scylladb.com/technology/ycsb-cassandra-scylla/#results-of-3-scylla-nodes-vs-30-cassandra-nodes>
>
>         They are claiming a 10x improvement, is that a fair comparison
>         or maybe a somewhat coloured view of a (micro)benchmark in a
>         specific setup? Any pros/cons known?
>
>         Best regards,
>
>         Robin Verlangen
>         Chief Data Architect
>
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>
>         On Wed, Dec 16, 2015 at 11:52 AM, Carlos Rolo
>         <rolo@pythian.com
>         <mailto:rolo@pythian.com><mailto:rolo@pythian.com
>         <mailto:rolo@pythian.com>>> wrote:
>         No rain at all! But I almost had it running last weekend, but
>         stopped short of installing it. Let's see if this one is for real!
>
>         Regards,
>
>         Carlos Juzarte Rolo
>         Cassandra Consultant
>
>         Pythian - Love your data
>
>         rolo@pythian | Twitter: @cjrolo | Linkedin:
>         linkedin.com/in/carlosjuzarterolo
>         <http://linkedin.com/in/carlosjuzarterolo><http://linkedin.com/in/carlosjuzarterolo
>         <http://linkedin.com/in/carlosjuzarterolo>>
>         Mobile: +351 91 891 81 00
>         <tel:%2B351%2091%20891%2081%2000><tel:+351%20918%20918%20100>
>         | Tel: +1 613 565 8696 x1649
>         <tel:%2B1%20613%20565%208696%20x1649><tel:+1%20613-565-8696>
>         www.pythian.com
>         <http://www.pythian.com><http://www.pythian.com/
>         <http://www.pythian.com/>>
>
>         On Wed, Dec 16, 2015 at 12:38 AM, Dani Traphagen
>         <dani.traphagen@datastax.com
>         <mailto:dani.traphagen@datastax.com><mailto:dani.traphagen@datastax.com
>         <mailto:dani.traphagen@datastax.com>>> wrote:
>         You'll be the first Carlos.
>
>         [Inline image 1]
>
>         Had any rain lately? Curious how this went, if so.
>
>         On Thu, Nov 12, 2015 at 4:36 AM, Jack Krupansky
>         <jack.krupansky@gmail.com
>         <mailto:jack.krupansky@gmail.com><mailto:jack.krupansky@gmail.com
>         <mailto:jack.krupansky@gmail.com>>> wrote:
>         I just did a Twitter search on scylladb and did not see any
>         tweets about actual use, so far.
>
>
>         -- Jack Krupansky
>
>         On Wed, Nov 11, 2015 at 10:54 AM, Carlos Alonso
>         <info@mrcalonso.com
>         <mailto:info@mrcalonso.com><mailto:info@mrcalonso.com
>         <mailto:info@mrcalonso.com>>> wrote:
>         Any update about this?
>
>         @Carlos Rolo, did you tried it? Thoughts?
>
>         Carlos Alonso | Software Engineer |
>         @calonso<https://twitter.com/calonso
>         <https://twitter.com/calonso>>
>
>         On 5 November 2015 at 14:07, Carlos Rolo <rolo@pythian.com
>         <mailto:rolo@pythian.com><mailto:rolo@pythian.com
>         <mailto:rolo@pythian.com>>> wrote:
>         Something to do on a expected rainy weekend. Thanks for the
>         information.
>
>         Regards,
>
>         Carlos Juzarte Rolo
>         Cassandra Consultant
>
>         Pythian - Love your data
>
>         rolo@pythian | Twitter: @cjrolo | Linkedin:
>         linkedin.com/in/carlosjuzarterolo
>         <http://linkedin.com/in/carlosjuzarterolo><http://linkedin.com/in/carlosjuzarterolo
>         <http://linkedin.com/in/carlosjuzarterolo>>
>         Mobile: +351 91 891 81 00
>         <tel:%2B351%2091%20891%2081%2000><tel:%2B351%2091%20891%2081%2000>
>         | Tel: +1 613 565 8696 x1649
>         <tel:%2B1%20613%20565%208696%20x1649><tel:%2B1%20613%20565%208696%20x1649>
>         www.pythian.com
>         <http://www.pythian.com><http://www.pythian.com/
>         <http://www.pythian.com/>>
>
>         On Thu, Nov 5, 2015 at 12:07 PM, Dani Traphagen
>         <dani.traphagen@datastax.com
>         <mailto:dani.traphagen@datastax.com><mailto:dani.traphagen@datastax.com
>         <mailto:dani.traphagen@datastax.com>>> wrote:
>         As of two days ago, they say they've got it @cjrolo.
>
>         https://github.com/scylladb/scylla/wiki/RELEASE-Scylla-0.11-Beta
>         <https://github.com/scylladb/scylla/wiki/RELEASE-Scylla-0.11-Beta>
>
>
>         On Thursday, November 5, 2015, Carlos Rolo <rolo@pythian.com
>         <mailto:rolo@pythian.com><mailto:rolo@pythian.com
>         <mailto:rolo@pythian.com>>> wrote:
>         I will not try until multi-DC is implemented. More than an
>         month has passed since I looked for it, so it could possibly
>         be in place, if so I may take some time to test it.
>
>         Regards,
>
>         Carlos Juzarte Rolo
>         Cassandra Consultant
>
>         Pythian - Love your data
>
>         rolo@pythian | Twitter: @cjrolo | Linkedin:
>         linkedin.com/in/carlosjuzarterolo
>         <http://linkedin.com/in/carlosjuzarterolo><http://linkedin.com/in/carlosjuzarterolo
>         <http://linkedin.com/in/carlosjuzarterolo>>
>         Mobile: +351 91 891 81 00
>         <tel:%2B351%2091%20891%2081%2000><tel:%2B351%2091%20891%2081%2000>
>         | Tel: +1 613 565 8696 x1649
>         <tel:%2B1%20613%20565%208696%20x1649><tel:%2B1%20613%20565%208696%20x1649>
>         www.pythian.com
>         <http://www.pythian.com><http://www.pythian.com/
>         <http://www.pythian.com/>>
>
>         On Thu, Nov 5, 2015 at 9:37 AM, Jon Haddad
>         <jonathan.haddad@gmail.com <mailto:jonathan.haddad@gmail.com>>
>         wrote:
>         Nope, no one I know.  Let me know if you try it I'd love to
>         hear your feedback.
>
>         > On Nov 5, 2015, at 9:22 AM, tommaso barbugli
>         <tbarbugli@gmail.com <mailto:tbarbugli@gmail.com>> wrote:
>         >
>         > Hi guys,
>         >
>         > did anyone already try Scylladb (yet another fastest NoSQL
>         database in town) and has some thoughts/hands-on experience to
>         share?
>         >
>         > Cheers,
>         > Tommaso
>
>
>
>
>         --
>
>
>
>
>         --
>         Sent from mobile -- apologizes for brevity or errors.
>
>
>
>         --
>
>
>
>
>
>
>
>         --
>         [datastax_logo.png]<http://www.datastax.com/
>         <http://www.datastax.com/>>
>
>         DANI TRAPHAGEN
>
>         Technical Enablement Lead | dani.traphagen@datastax.com
>         <mailto:dani.traphagen@datastax.com><mailto:dani.traphagen@datastax.com
>         <mailto:dani.traphagen@datastax.com>>
>
>         [twitter.png]<https://twitter.com/dtrapezoid
>         <https://twitter.com/dtrapezoid>> [linkedin.png]
>         <https://www.linkedin.com/pub/dani-traphagen/31/93b/b85
>         <https://www.linkedin.com/pub/dani-traphagen/31/93b/b85>>
>         [https://lh5.googleusercontent.com/WcFJcWZHKXnxu01V6zJIQapcGonoazqsv8O7_DtfhW-qbTRHxDjfX2owDNmQhgojRx5Y4mLEc-KiAeeTJjT0VmKiiIld8UP86AgQPJDK2o6oC6BhTmub4NLZ_MO9-E7l9Q
>         <https://lh5.googleusercontent.com/WcFJcWZHKXnxu01V6zJIQapcGonoazqsv8O7_DtfhW-qbTRHxDjfX2owDNmQhgojRx5Y4mLEc-KiAeeTJjT0VmKiiIld8UP86AgQPJDK2o6oC6BhTmub4NLZ_MO9-E7l9Q>]
>         <https://github.com/dtrapezoid>
>
>         [http://datastax.com/all/images/cs_logo_color_sm.png
>         <http://datastax.com/all/images/cs_logo_color_sm.png>]
>
>
>
>         --
>
>
>
>
>
>
>
>     -- 
>     -Richard L. Burton III
>     @rburton
>
>


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