ScyllaDB: Drop-in replacement for Cassandra that claims to be 10x faster

Post by kcw39217 » Wed, Sep 23, 2015, 2:52 PM UTC

glommer wrote: post #57

mbfg wrote: post #33

Wait, did I read that right? the test was with (1) one server? What's the point of that? Smells like a cooked up test.

The point of that is to show how efficient a node can be, because that is what is replaced. All the external facing things for scylla is the same as Cassandra. That includes all the ring stuff and all network protocols. So you should expect similar cluster behavior.

Post by bpicolo » Wed, Sep 23, 2015, 3:58 PM UTC

kcw39217 wrote: post #61

glommer wrote: post #57

Earlier quoted context omitted.

The point of that is to show how efficient a node can be, because that is what is replaced. All the external facing things for scylla is the same as Cassandra. That includes all the ring stuff and all network protocols. So you should expect similar cluster behavior.

Cassandra is an open source distributed database management system designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure....... There is nothing commodity about a server with 128GB RAM. When you introduce other nodes, you get chatter and network traffic....

Post by cbsmith » Wed, Sep 23, 2015, 4:03 PM UTC

jandrewrogers wrote: post #45

est wrote: post #28

Earlier quoted context omitted.

I really appreciate your insight, but I didn't understand why you keep implying "open source" as some kind of lack-behind design?

In practice, open source databases use more traditional, simpler architectures for which there is a lot of literature. Ironically, you see a lot more creativity and experimentation in closed source database architectures, and this has accrued some substantial benefits to those implementations. The architecture at the link looks unusual compared to open source databases but it is actually a common architecture pattern…

Post by cbsmith » Wed, Sep 23, 2015, 4:09 PM UTC

_Codemonkeyism wrote: post #47

_Codemonkeyism wrote: post #25

Earlier quoted context omitted.

10x speedup (same algorithms, same architecture) replacing Java with C++ is not possible (~2x at max). One of the latest benchmarks I've seen is "Comparison of Programming Languages in Economics" [1] for code without any IO just number crunching, has a 1.91 to 2.69 speedup of using C++ compared to Java. So any code involving IO is going to be slower. Replacing bad Java code with excellent machine aligned C++ a 10x sp…

[Edit: The LMAX guys showed how much more performance is possible with aligning code with CPU/hardware (in this case for Java) http://mechanical-sympathy.blogspot.de/ ]

Post by vitalyd » Wed, Sep 23, 2015, 4:51 PM UTC

cbsmith wrote: post #66

glommer wrote: post #50

Earlier quoted context omitted.

IO is not only a large part. It is the main part. That is why it is important to get it right : scylla for instance does not leave the cache to the OS. It has its own caches for everything. Never blocks on IO or page faults because all IO bypasses the kernel. And those are just two tiny examples.

> scylla for instance does not leave the cache to the OS. It has its own caches for everything Uh-huh... that's all pretty common for databases. Cassandra would fit that description. > Never blocks on IO or page faults because all IO bypasses the kernel. That just seems nonsensical. Sometimes, you are waiting for IO. That's just reality. It is conceivable you bypass the kernel for I/O, but that creates a lot of compl…