I don't think it's coming full circle. They're just properly separating the project code, so that the time critical code is in C/C++ while the scale/fault-tolerant code will be in Erlang.
The real drug on performance is using javascript for queries & M/R and HTTP-based APIs vs. binary protocols.
Moving to UnQL and Memcached protocol may solve some of the performance problems.
There is a reason antirez choose Lua and not JS for a scripting language.
I agree with much of what you've said there. You clearly understand enough that I don't need to go into detail describing why I agree. :) But this isn't quite right:
> There is a reason antirez choose Lua and not JS for a scripting language.
To be fair, I embedded lua in ep-engine well over a year ago, but haven't ever released it. As it turns out, v8 is performing very well lately (certainly faster than plain lua) and people get it more easily. I've done some fun things with lua and it's really fun and easy to embed, but whatever gets shipped has to be supported and lua has some pretty dark areas.
