I'm +1 on the idea of a pluggable storage engine. There's clearly a bandwidth problem for developing/reviewing/maintain multiple storage engines, but I think having the interface is a good thing and can enhance testability.
At a minimum I think it's worthwhile to explore the storage engine interface, although it may turn out that it's infeasible/impractical given the current system. And that's OK. Thanks, -Jason On Thu, Apr 20, 2017 at 4:25 PM, Jeff Jirsa <jji...@gmail.com> wrote: > Let's try to make this actionable. Long time > contributors/committers/members of the PMC (especially you guys who have > been working on internals for 4-8 years): > > Setting aside details of the implementation, does anyone feel that > pluggable storage in itself is inherently a bad idea (so much so that you'd > -1 it if someone else did the work)? > > If we can establish loose consensus on it being something generally > acceptable (assuming someone can come up with an interface/abstraction upon > which everyone can agree), then it seems like the next step is working on > defining the proper interface. > > - Jeff > > > On Wed, Apr 19, 2017 at 9:21 AM, Dikang Gu <dikan...@gmail.com> wrote: > > > Hi Cassandra developers, > > > > This is Dikang from Instagram, I'd like to share you some experiment > > results we did recently, to use RocksDB as Cassandra's storage engine. In > > the experiment, I built a prototype to integrate Cassandra 3.0.12 and > > RocksDB on single column (key-value) use case, shadowed one of our > > production use case, and saw about 4-6X P99 read latency drop during peak > > time, compared to 3.0.12. Also, the P99 latency became more predictable > as > > well. > > > > Here is detailed note with more metrics: > > > > https://docs.google.com/document/d/1Ztqcu8Jzh4USKoWBgDJQw82DBurQm > > sV-PmfiJYvu_Dc/edit?usp=sharing > > > > Please take a look and let me know your thoughts. I think the biggest > > latency win comes from we get rid of most Java garbages created by > current > > read/write path and compactions, which reduces the JVM overhead and makes > > the latency to be more predictable. > > > > We are very excited about the potential performance gain. As the next > step, > > I propose to make the Cassandra storage engine to be pluggable (like > Mysql > > and MongoDB), and we are very interested in providing RocksDB as one > > storage option with more predictable performance, together with > community. > > > > Thanks. > > > > -- > > Dikang > > >
