[Shorel]

No, just because it's in C++ does not mean it is automatically faster.

However, with good enough algorithms and judicious coding and memory management, the possibility exists.

[danudey]

Also, architectural changes. They describe how ES can't parallelize a query unless it's spread across multiple index shards, which has its own tradeoffs. Their query engine can parallelize a query on a single index shard, which means it scales much more linearly on more cores without having to make those tradeoffs.

[pjmlp]

Which could also be done in Java.

[pjmlp]

Same can be said by Java, even without direct support for value types.

Plus it doesn't need to be Java xor C++, JNI exists for a reason (now Panama).