On Tue, Sep 7, 2021 at 5:06 PM bened...@apache.org <bened...@apache.org> wrote:
> > I was thinking that a path similar to Calvin/FaunaDB is certainly > looming in the horizon at least. > > I’m not sure which aspect of these systems you are referring to. Unless I > have misunderstood, I consider them to be strictly inferior approaches > (particularly for Cassandra) as they require a _global_ leader process and > as a result have scalability limits. Users simply shift the sharding > problem to the cluster level rather than the node level, but the > fundamental problem remains. This may be acceptable for many users, but was > contrary to the goals of this CEP. > Oh yes. For sure it's one of the strengths of the CEP that it is clearly designed to fit well into the existing Cassandra architecture and experience. I was referring to the property that Calvin transactions also need to be sent to the cluster in a single shot, but then they have extended the functionality by allowing programming logic to be executed inside the transaction. (Like a stored procedure, if you will.) So the transactions can be multi-statement with complex logic, they just can't communicate outside the cluster - such as back and forth with the client and server. > > good job pulling together ingredients from state of the art work in this > area > > In case this was lost in the noise: this work is not simply an assembly of > prior work. It introduces entirely novel approaches that permit the work to > exceed the capabilities of any prior research or production system. It is > worth properly highlighting that if we deliver this, Cassandra will have > the most sophisticated transaction system full stop. > > Of course. Maybe it's just me, but I'm at least equally impressed by the "level of education" the authors show in not reinventing the wheel for the details where copying a feature, or at least being inspired by one, from some existing publication or implementation was possible. Knowing what to keep vs what you want to improve isn't easy. Also, it makes the whitepaper an interesting read when in addition to learning about Accord I also learned about several other systems that I hadn't previously read about. henrik
